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Improving nitrogen fertilizer recommendations for arable crops in the Lower Fraser Valley Weinberg, Naomi Hélène 1987

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IMPROVING FOR  NITROGEN  ARABLE  CROPS  FERTILIZER IN THE  RECOMMENDATIONS  LOWER  FRASER  VALLEY  by NAOMI H E L E N E B.Sc.  (Honours) U n i v e r s i t y  A THESIS THE  SUBMITTED  WEINBERG  of Newcastle  IN PARTIAL  REQUIREMENTS MASTER  FOR OF  THE  Upon  Tyne,  FULFILLMENT DEGREE  OF  SCIENCE  in FACULTY  We  GRADUATE  (Department  of S o i l  accept  thesis  to  THE  OF  this  the required  UNIVERSITY  OF  April @  Naomi  Helene  STUDIES Science)  as  conforming  standard  BRITISH  COLUMBIA  1987 Weinberg,  1987  OF  1983  In  presenting  degree  this  at the  thesis  in partial fulfilment  University of  freely available for reference copying  of  department publication  this or of  British Columbia, and study.  by this  his  or  her  the  The University of British Columbia 1956 Main Mall Vancouver, Canada V6T 1Y3  that the  I further agree  representatives.  may be It  thesis for financial gain shall not  Department  requirements  I agree  thesis for scholarly purposes  permission.  DE-6(3/81)  of  for  an  advanced  Library shall make it  that permission  for extensive  granted  head  is  by the  understood be  that  allowed without  of  my  copying  or  my written  ABSTRACT  A two year f i e l d study l o c a t e d i n D e l t a M u n i c i p a l i t y , Columbia, of  was conducted to i n v e s t i g a t e  nitrogen  the p o s s i b l e  British  improvement  (N) f e r t i l i z e r recommendations f o r a r a b l e c r o p s i n  the Lower F r a s e r V a l l e y  (LFV).  A f t e r r e v i e w i n g c u r r e n t N f e r t i l i z e r recommendation systems i n other humid r e g i o n s ,  the approach taken i n the study was to  determine the a p p l i c a b i l i t y of a s p r i n g s o i l t e s t a n d / o r a N Index system f o r the LFV r e g i o n . corn (Zea Mays s a c c h a r a t a ) interconnected  The p r o j e c t ,  as the t r i a l  crop,  which used sweet consisted  two  parts:  1) A ' R e p l i c a t e d F e r t i l i z e r Response T r i a l ' a)  of  which aimed t o ;  Monitor s o i l N 0 - N and NH -N d u r i n g s p r i n g to a depth of 80cm, 3  using i n t e r v a l s of 0-20, y i e l d response sidedress  4  20-50,  and 50-80cm.  and N uptake e f f i c i e n c y  a p p l i e d urea, 0,  50,  b)  Investigate  at f o u r d i f f e r e n t  100 and 200 kg h a  - 1  N.  the e f f e c t i v e n e s s of urea a p p l i e d broadcast p r e p l a n t , by s i d e d r e s s i n g ,  of  Compare  and a p p l i e d  when the crop was approximately 30cm t a l l .  2) A ' M u l t i f a r m Survey' at 28 l o c a t i o n s ,  comparing p l o t s  sidedressed  with 135 kg h a  s t a r t e r N.  The aim of t h i s survey vas to e s t a b l i s h  N supplying capacities capacities  c)  rates  - 1  N, to c o n t r o l p l o t s c o n t a i n i n g only  i n some LFV s o i l s and r e l a t e  to other s o i l p r o p e r t i e s and s i t e  the range of these  history.  M o n i t o r i n g m i n e r a l N i n the s o i l demonstrated t h a t s o i l i n c r e a s e d d u r i n g the s p r i n g , r e a c h i n g a peak 5-6 weeks a f t e r  ii  N0 -N 3  planting. 135  kg  t o be  Maximum N0 -N l e v e l s i n t h e  ha"  i n 1984  1  low  t o between  two  10  No  and  15%  by  which c o u l d  mid  due  not  be  Response T r i a l .  were f o u n d  i n the  starter  fertilizing  soil  and  weather  the  Delta  by  soil  to the  t y p e s and  soil.  too  a knowledge o f  of  spatial  and  and  on  the  N  weather  or crop N  fertilizer  by  significant by  one,  in  the  differences  broadcasting  sidedressing.  N f o r the  content  treatments  urea N a p p l i e d  Two  that  the  c r o p ' s needs,  reasons soil  and  plus  two,  considering  site be  the  greatest  amount  project's objectives. cropping  r e g i m e s on  N supplying  matter,  the  h i s t o r y was  relationship  could  favoured  implementation  the  May,  the  of  I t showed  corn  fields  that in  n a r r o w t o have a d i r e c t i n f l u e n c e on  Soil  weakly r e l a t e d t o o r g a n i c that  yield  S i m i l a r l y , no  Survey provided  relevant  the  of  mineral  site  t e c h n i q u e s were i n e f f i c i e n t  M u n i c i p a l i t y was  supplied  beginning  N,  conditions.  Multifarm  range of  four  sufficient  the  mineral  N H « - N were o b s e r v e d  r e s p o n s e were s u g g e s t e d ,  N provided  information  the  urea N a p p l i e d  that  The  of  and  separated.  comparison  and  total  L a r g e amounts o f  d i f f e r e n c e s i n corn  Replicated  lack of  at the  t o a l a r g e number o f  between any  this  June.  of  d i f f e r e n c e i n magnitude of  were f o u n d  for  25%  were 90  NH«-N l e v e l s tended  a proportion  3  y e a r s was  planting  As  i n b o t h N0 -N and The  significant  before  respectively.  from a p p r o x i m a t e l y  studied.  between t h e  1985  t o NOj-N.  variability  sites  factors  and  compared  NH*-N d e c r e a s e d  temporal  0-80cm p r o f i l e  3  assumed t o be of  was  shown t o  be  study r e s u l t s suggested necessary  positive.  a spring  iii  capacity  N  soil  before Such  this  findings  test rather  than a N  Index s y s t e m .  Various  requirements using In c o n c l u s i o n ,  approaches t o e s t i m a t i n g  a spring  soil  the project  consideration  study  suggested  showed t h a t  Municipality, correlated further should  or  spring  with t o t a l  be a s c l o s e  compaction  appeared  soil  N0 -N 3  plus  t e s t f o r N. to sidedress  n o t be i n c l u d e d  well  t o warrant the This  t e s t , f o r corn,  t i m e and t h e i d e a l  Anomalous s i t e s  such as poor drainage,  The  such as D e l t a  t o be s u f f i c i e n t l y  crop nitrogen  iv  be t a k e n  r e c o m m e n d a t i o n s a r e made.  soil  as p o s s i b l e  should  these should  a g r i c u l t u r a l region  d e p t h would be t o 80cm.  conditions,  and t h a t  s u b s t a n t i a l amounts o f  i n a small  investigation of a s o i l  sampling soil  when f e r t i l i z e r  that  fertilizer  s a m p l e were e x a m i n e d .  N v e r e made a v a i l a b l e by t h e s o i l into  N  with  adverse  marine i n f l u e n c e s ,  i n the test.  low pH  TABLE OF CONTENTS PAGE ABSTRACT  i i  TABLE OF CONTENTS  v  LIST OF TABLES.  viii  LIST OF FIGURES  x  LIST OF APPENDICES  xi  ACKNOWLEDGEMENTS.  xiii  1. INTRODUCTION  1  1.1  N i t r o g e n f e r t i l i z e r and i t s use i n the Lower F r a s e r Valley  1  1.2  Objectives  5  2. LITERATURE REVIEW  6  2. 1 The N i t r o g e n Requirement Equation 6 2.1.1 The N i t r o g e n Requirement & 2. 1. 2 N i t r o g e n s u p p l i e d by the s o i l 8 2.1.3 N i t r o g e n s u p p l i e d by manure and f e r t i l i z e r 11 2.2 N i t r o g e n f e r t i l i z e r recommendations i n humid regions...14 2.2.1 P l a n t a n a l y s i s 14 2. 2. 2 S o i l sampling 18 M i n e r a l n i t r o g e n measurements 21 Estimating mineralization 23 S o i l sampling methods used i n Western Europe 25 S o i l sampling methods proposed i n E a s t e r n USA 28 2.2.3 S o i l N i t r o g e n Index Systems. 30 2. 2. 4 Computer m o d e l l i n g 34 2. 3 Approach used i n t h i s study 39 3. METHODS  42  3. 1 P r o j e c t d e s i g n 42 3. 2 F i e l d methods 44 3.2.1 N i t r o g e n M o n i t o r i n g Study, F e r t i l i z e r Response T r i a l and P r e p l a n t versus S i d e d r e s s Urea Study...44 Plot layout 45 Methods of f e r t i l i z a t i o n 45 S o i l measurements 46 Crop h a r v e s t 47 3.2.2 M u l t i f a r m Survey of s o i l n i t r o g e n s u p p l y i n g ability 48  v  3. 3 L a b o r a t o r y methods 3. 4 S t a t i s t i c a l a n a l y s i s  49 50  4. RESULTS AND DISCUSSION  52  4. 1 N i t r o g e n m o n i t o r i n g d u r i n g s p r i n g 53 4.1.1 S o i l m i n e r a l n i t r o g e n , magnitude and variability 53 4.1.2 S o i l ammonium 56 4.1.3 S o i l n i t r a t e and s o i l t e m p e r a t u r e 57 4.1.4 V a r i a b i l i t y o f b u l k d e n s i t y measurements 57 4.2 F e r t i l i z e r N i t r o g e n R e s p o n s e T r i a l a n d P r e p l a n t v e r s u s S i d e d r e s s Urea Study 60 4. 2. 1 C r o p r e s p o n s e t o f e r t i l i z e r 60 4. 3 M u l t i f a r m S u r v e y 63 4. 3. 1 S o i l n i t r o g e n s u p p l y i n g c a p a c i t i e s 63 4.3.2 B u l k d e n s i t i e s o f t h e M u l t i f a r m T r i a l s i t e s 65 4. 3. 3 S o i l n i t r o g e n a n d p r e v i o u s c r o p p i n g 65 4.3.4 S p r i n g s o i l n i t r o g e n and s o i l p r o p e r t i e s 67 O r g a n i c m a t t e r and t o t a l n i t r o g e n 68 S o i l texture 68 pH 70 Marine e f f e c t s 70 S o i l n i t r a t e measured by t h e Kelowna laboratory 71 4. 3. 5 S p r i n g s o i l n i t r o g e n a n d c o r n r e s p o n s e 73 Numbers o f t i l l e r s , c o b s and s t a l k s 77 Y i e l d s o f s t a l k s , c o b s and t h e whole p l a n t . . 7 7 Relative yield 79 S t a l k , c o b a n d whole p l a n t n i t r o g e n 80 4. 3. 6 C o r n r e s p o n s e on p r o b l e m s o i l s 81 5.  NITROGEN F E R T I L I Z E R RECOMMENDATIONS IN THE LOWER FRASER VALLEY - INTERPRETATION OF THE RESULTS 5. 1 N i t r o g e n r e q u i r e m e n t f o r sweet c o r n 5. 2 N i t r o g e n s u p p l i e d by t h e s o i l 5.2.1 S o i l s a m p l i n g v e r s u s a N i t r o g e n Index System 5. 2. 2 I m p l e m e n t i n g a s p r i n g s o i l t e s t Depth o f s a m p l i n g Time o f s a m p l i n g 5.2.3 Estimating s o i l a v a i l a b l e nitrogen using h a r v e s t - t i m e measurements 5.2.4 P r e d i c t i n g s o i l a v a i l a b l e n i t r o g e n from n i t r a t e found at s i d e d r e s s time 5.3 E f f i c i e n c y o f c r o p u p t a k e o f s o i l m i n e r a l n i t r o g e n 5.4 E f f i c i e n c y o f c r o p u p t a k e o f f e r t i l i z e r n i t r o g e n 5.5 N i t r o g e n s u p p l i e d by f e r t i l i z e r a n d / o r manure 5. 5. 1 E s t i m a t i n g f e r t i l i z e r r e q u i r e m e n t s u s i n g t h e N i t r o g e n Requirement Equation 5.5.2 Estimating f e r t i l i z e r requirements using the r e l a t i o n s h i p s between c r o p r e s p o n s e and s o i l nitrate  vi  83 83 86 86 89 89 90 90 94 98 100 101 101 102  Estimating f e r t i l i z e r requirements using t h e l i n e a r r e l a t i o n s h i p between c r o p r e s p o n s e and s o i l n i t r a t e Estimating f e r t i l i z e r requirements using t h e l o g a r i t h m i c r e l a t i o n s h i p between c r o p r e s p o n s e and s o i l n i t r a t e  103 105  6. CONCLUSIONS  114  7. REFERENCES.  117  8. APPENDICES  126  vii  LIST OF TABLES PAGE Table 1. P r e c i p i t a t i o n Sept. 1985  and temperature  summaries Oct. 1983 3  Table 2.1 Approximate t o t a l N content and d i s t r i b u t i o n i n good y i e l d s o f some major crops  7  Table 2.2 General summary o f c u r r e n t s o i l n i t r o g e n e v a l u a t i o n systems i n v a r i o u s r e g i o n s o f the U n i t e d S t a t e s 19 Table 2.3a E s s e n t i a l data o f N . „ method f o r crops grown on deep s o i l s  27  Table 2.3b Rapid n i t r o g e n t e s t b e f o r e the u s u a l date o f top d r e s s i n g f o r winter wheat  27  Table 2. 4 N i t r o g e n Index - based  33  t  on l a s t crop grown  Table 2.5 Summary o f processes c o n s i d e r e d i n the s i x models presented a t the N i t r o g e n C y c l e S i m u l a t i o n Model Workshop - Netherlands 1983  36  Table 4. 1 S o i l n i t r a t e d u r i n g s p r i n g 1984 and 1985  55  Table 4. 2 S o i l ammonium d u r i n g s p r i n g 1984 and 1985  55  Table 4.3 R e p l i c a t e d F e r t i l i z e r Response T r i a l : Means and c o e f f i c i e n t s o f v a r i a t i o n f o r n i t r a t e and bulk density  59  Table 4.4 R e p l i c a t e d F e r t i l i z e r Response T r i a l , Urea P r e p l a n t versus S i d e d r e s s T r i a l 1984, 1985: Corn data, s i t e means and c o e f f i c i e n t s o f v a r i a t i o n 61 Table 4.5 R e p l i c a t e d F e r t i l i z e r Response T r i a l 1984, 1985: S o i l n i t r a t e , means and c o e f f i c i e n t s o f v a r i a t i o n b e f o r e p l a n t i n g and a t s i d e d r e s s time  62  Table 4.6 M u l t i f a r m T r i a l : S o i l n i t r a t e and ammonium at s i d e d r e s s time, mean and range over 27 s i t e s  64  Table 4.7 M u l t i f a r m T r i a l :  Bulk d e n s i t y , range and averages...66  T a b l e 4.8 M u l t i f a r m T r i a l : S o i l parameter ranges and s i g n i f i c a n t c o r r e l a t i o n s a t t h r e e depths between s o i l c h a r a c t e r i s t i c s and ' F i e l d M o i s t ' e x t r a c t e d s o i l n i t r a t e a t s i d e d r e s s time  viii  69  T a b l e 4.9 M u l t i f a r m T r i a l : S i g n i f i c a n t c o r r e l a t i o n s between s o i l / c r o p parameters and s o i l n i t r a t e ( s i d e d r e s s time) e x t r a c t e d by the'Kelowna' and ' F i e l d M o i s t ' methods  72  Table 4.10a M u l t i f a r m T r i a l : S i g n i f i c a n t c o r r e l a t i o n s between s o i l n i t r a t e and ammonium e x t r a c t e d ' F i e l d M o i s t ' and corn y i e l d parameters  74  T a b l e 4.10b M u l t i f a r m T r i a l : S i g n i f i c a n t c o r r e l a t i o n s between s o i l n i t r a t e and ammonium e x t r a c t e d ' F i e l d M o i s t ' and corn y i e l d parameters  75  Table 4.10c M u l t i f a r m T r i a l : S i g n i f i c a n t c o r r e l a t i o n s between s o i l n i t r a t e and ammonium e x t r a c t e d ' F i e l d M o i s t ' and corn y i e l d parameters  76  Table 4.11 M u l t i f a r m T r i a l , Problem s o i l s : S e l e c t e d c o r r e l a t i o n s between crop parameters and s o i l n i t r a t e , problem s i t e s excluded  62  Table 5.1 M u l t i f a r m T r i a l : E s t i m a t i n g n i t r o g e n s u p p l i e d by the s o i l . L i n e a r r e g r e s s i o n s between crop n i t r o g e n p l u s s o i l m i n e r a l n i t r o g e n a t h a r v e s t and s o i l m i n e r a l n i t r o g e n at s i d e d r e s s 95 T a b l e 5.2 N i t r o g e n F e r t i l i z e r Recommendations: C r i t i c a l ranges o f n i t r a t e d i v i d i n g r e s p o n s i v e and unresponsive s i t e s u s i n g t h e Cate-Nelson method....112  ix  LIST OF FIGURES PAGE F i g u r e 1. Annual water balance o f the Lower F r a s e r V a l l e y F i g u r e 2. Measured and s i m u l a t e d course of n i t r a t e - n i t r o g e n i n the a r a b l e l a y e r and i n the upper 60cm F i g u r e 3. M u l t i f a r m  Trial:  Municipality,  4 37  Plot locations, Delta  B r i t i s h Columbia  F i g u r e 4.1 S o i l n i t r a t e t o a depth o f 80cm d u r i n g s p r i n g F i g u r e 4.2 R e l a t i o n s h i p between s o i l n i t r a t e (0-20cm depth) and s o i l temperature F i g u r e 5.1 R e l a t i o n s h i p between t o t a l corn n i t r o g e n and cob yield, fresh  43 54 58 84  F i g u r e 5.2 R e l a t i o n s h i p between m i n e r a l i z a t i o n as a p r o p o r t i o n o f o r g a n i c matter and o r g a n i c matter (0-50cm)  88  F i g u r e 5.3 R e l a t i o n s h i p between m i n e r a l i z a t i o n and s o i l m i n e r a l n i t r o g e n (0-50cm) at s i d e d r e s s  93  F i g u r e 5.4 R e l a t i o n s h i p between s o i l n i t r a t e (0-80cm) p l u s crop n i t r o g e n at h a r v e s t and s o i l n i t r a t e (0-80cm) at s i d e d r e s s 97 F i g u r e 5.5 R e l a t i o n s h i p between crop n i t r o g e n uptake and t o t a l crop p l u s s o i l n i t r o g e n at h a r v e s t  99  F i g u r e 5.6 R e l a t i o n s h i p between cob y i e l d , f r e s h and s o i l n i t r a t e (0-80cm) a t s i d e d r e s s . . . . .  104  F i g u r e 5.7 R e l a t i o n s h i p between s t a l k y i e l d , f r e s h and s o i l n i t r a t e (0-20cm) at s i d e d r e s s showing p o p u l a t i o n s p l i t u s i n g the Cate-Nelson method  107  F i g u r e 5.8 R e l a t i o n s h i p between whole p l a n t y i e l d , f r e s h and s o i l n i t r a t e (0-20cm) a t s i d e d r e s s showing p o p u l a t i o n s p l i t u s i n g the Cate-Nelson method  108  F i g u r e 5.9 R e l a t i o n s h i p between r e l a t i v e y i e l d , f r e s h and s o i l n i t r a t e <0-50cm) at s i d e d r e s s showing p o p u l a t i o n s p l i t u s i n g the Cate-Nelson method  109  x  LIST OF APPENDICES PAGE Appendix 1. D a i l y p r e c i p i t a t i o n Apr. - Sept. Appendix 2. S o i l  1984/1985  126  c h a r a c t e r i s t i c s of Reynelda Farm s i t e s  Appendix 3. F i e l d p l a n example, R e p l i c a t e d Response T r i a l , S i t e A  127  Fertilizer 128  Appendix 4. Q u e s t i o n n a i r e sent t o farmers t o o b t a i n s i t e information  129  Appendix 5. Methods used f o r s o i l a n a l y s i s by B. C. Feed and T i s s u e T e s t i n g Laboratory, Kelowna  130  Appendix 6. M u l t i f a r m T r i a l : P r e v i o u s cropping, m i n e r a l i z a t i o n , crop p l u s s o i l n i t r o g e n (0-80cm) and f e r t i l i z e r e f f i c i e n c y e s t i m a t e s 131 Appendix 7. M u l t i f a r m T r i a l : S o i l n i t r a t e and ammonium (kg h a ) at s i d e d r e s s  132  Appendix 8a. N i t r o g e n m o n i t o r i n g study: 1) 25 A p r i l 2) 9 May 1984  133  - 1  Appendix 8b. N i t r o g e n m o n i t o r i n g study: 1) 23 May 2) 7 June 1984  1984 134  Appendix 8c. N i t r o g e n m o n i t o r i n g study: 1) 20 June 2) 4 J u l y 1984 Appendix 8d. N i t r o g e n m o n i t o r i n g study: 1) 8 May 2) 22 May 1985  1984  1984 135  1985 136  Appendix 8e. N i t r o g e n m o n i t o r i n g study: 1) 5 June 2) 19 June 1985  1985  Appendix 8f. N i t r o g e n m o n i t o r i n g study: 1) 2 J u l y 2) 16 J u l y 1985  1985  Appendix 9a. R e p l i c a t e d f e r t i l i z e r preplant  response  Appendix 9b. R e p l i c a t e d f e r t i l i z e r sidedress  response  Appendix 9c. R e p l i c a t e d f e r t i l i z e r harvest  response  Appendix 10. R e p l i c a t e d f e r t i l i z e r  response  xi  trial:  137 138 Soil  data, 139  trial:  Soil  data, 140  trial:  Soil  data, 141  trial:  Corn data.142  Appendix Appendix  Appendix  11a.  Preplant versus data, p r e p l a n t  s i d e d r e s s urea  trial:  143  l i b . P r e p l a n t versus s i d e d r e s s urea data, s i d e d r e s s  trial:  11c.  trial:  Preplant data,  Soil  versus  s i d e d r e s s urea  Soil 144 Soil  harvest  Appendix  12.  Appendix  13a.  Multifarm  trial:  Site  properties  147  Appendix  13b.  Multifarm  trial:  Site properties  148  Appendix  13c.  Multifarm  trial:  Site properties  149  Appendix  13d.  Multifarm  trial:  Site properties  150  Appendix  14a.  data  from c o n t r o l  Appendix  14b.  Multifarm t r i a l : S o i l at s i d e d r e s s Multifarm t r i a l : S o i l p l o t s at sidedress  data  from f e r t i l i z e d  Multifarm t r i a l : at harvest  Soil  data  Multifarm  Soil  Appendix Appendix  14c. 14d.  Preplant  plots  versus  145 s i d e d r e s s urea  trial:  trial:  Corn  data.146  plots 151 152  from c o n t r o l  plots 153  data  from f e r t i l i z e d  at harvest  Multifarm  trial:  154  Appendix  15.  Kelovna s o i l  Appendix  16a.  Multifarm  trial:  Corn data  156  Appendix  16b.  Multifarm  trial:  Corn data  157  Appendix  16c.  Multifarm  trial:  Corn data.  158  Appendix  16d.  Multifarm  trial:  Corn data  159  xii  n i t r a t e v a l u e s . . . . 155  ACKNOWLEDGEMENTS  I wish t o thank my s u p e r v i s o r . advice,  support  and p a t i e n c e  Dr. A r t Bomke, f o r h i s  regarding  t h i s endeavour.  I also  thank him f o r h i s help d u r i n g t h e f i e l d seasons and extend s i m i l a r thanks t o E l i z a b e t h Deom and Dave McKimm my hardworking summer a s s i s t a n t s .  I would a l s o l i k e t o 'thank t h e many  people who a s s i s t e d with h a r v e s t i n g I am indebted for  p l o t s t o be l o c a t e d on t h e i r  I am a l s o e s p e c i a l l y g r a t e f u l t o Mr. I r v i n e S c h i n k e l  of Royal C i t y Foods, without h i s c o o p e r a t i o n Survey c o u l d not have e x i s t e d .  f o r the p r o j e c t .  l a b o r a t o r y a n a l y s i s c o u l d i n no way have been completed  without t h e a s s i s t a n c e , p a t i e n c e and  the Multifarm  The B.C.A.S.C.C. a r e a l s o  thanked f o r p r o v i d i n g f i n a n c i a l support The  corn.  t o Mr. Hugh Reynolds and Mr. John Malenstyn  a l l o w i n g t h e experimental  fields.  and e a t i n g t h e sweet  and good humour o f P a t t i  Carbis  E v e l i n e Wolterson, these two t e c h n i c i a n s cannot be thanked  enough.  The B.C. Feed and T i s s u e T e s t i n g Laboratory,  i s also appreciated  Kelowna,  f o r providing gratuitously their services  for  a n a l y z i n g the M u l t i f a r m  Survey s o i l s .  I am a l s o g r a t e f u l  for  t h e a s s i s t a n c e o f Bruce M c G i l l v r a y r e g a r d i n g  t h e computer  analyses. I finally  thank my f r i e n d  Ian E l l i o t who p e r s i s t e n t l y  encouraged me d u r i n g t h e arduous p a r t s o f t h i s p r o j e c t and a l l those who read t h e t h e s i s and provided notably and  constructive c r i t i c i s m  my committee members Mr. Ron Bertrand,  Dr. Les L a v k u l i c h .  xiii  Dr.Lawrence Lowe  1  1. INTRODUCTION  1.1  NITROGEN FERTILIZER AND  Over the past 30 years, production  has  ITS USE  IN THE  world f e r t i l i z e r  nitrogen  (N)  i n c r e a s e d from approximately 5 m i l l i o n tonnes t o  almost 50 m i l l i o n tonnes (Hignett 1985). N fertilizer  LOWER FRASER VALLEY  demand i s j u s t one  This large increase i n  i n d i c a t i o n of the  importance of N f o r a g r i c u l t u r a l crop  current  production.  N i s e s s e n t i a l i n a l l a g r i c u l t u r a l crops t o form p r o t e i n s and  c h l o r o p h y l l ; N d e f i c i e n c y i s d i s p l a y e d by a d i s t i n c t  chlorosis,  u s u a l l y s t a r t i n g i n the lower leaves,  leaves tending the p l a n t .  to remain green due  Inadequate N,  s o i l nutrients, w i l l g r a i n s and  the upper  t o the high m o b i l i t y of N i n  or an N imbalance r e l a t i v e t o  cause lowered p r o t e i n c o n c e n t r a t i o n s  i n general,  lowered  in  yields.  N i s the most commonly d e f i c i e n t p l a n t n u t r i e n t . amount of r e s e a r c h  other  l i t e r a t u r e regarding  The  N use shows t h a t  vast crops  i n most a g r i c u l t u r a l r e g i o n s of the world respond f a v o u r a b l y i n t e l l i g e n t l y a p p l i e d N; consequently, most c o u n t r i e s at  l e a s t some p r o p o r t i o n of t h e i r crops  F r a s e r V a l l e y (LFV)  with N.  to  fertilize  In the Lower  of B r i t i s h Columbia, the r e g i o n of  this  study, N a d d i t i o n i s a r o u t i n e management p r a c t i c e f o r growing a l l the major crops, The  i . e . hay  and  fodder,  vegetables,  problem however, i s t h a t farmers i n the LFV  about how  much N should  be  applied.  and  know very  corn. little  Present N f e r t i l i z e r  recommendations i n t h e LFV c o n s i s t o f a  s i n g l e r a t e o f N f o r an i n d i v i d u a l crop, as o u t l i n e d i n t h e publication,  "Fertilizer  Guide f o r t h e Lower Mainland" (B.C.  M i n i s t r y o f A g r i c u l t u r e 1977).  These recommendations do not  i n c o r p o r a t e any form o f s o i l t e s t f o r N, they take no account o f p r e v i o u s c r o p p i n g o r s o i l type, and pay only l i p s e r v i c e t o any manure a p p l i c a t i o n s , and s l u r r y ) .  ('Manure' i n t h i s t h e s i s r e f e r s t o manure  The r e s u l t o f such crude recommendations i s t h a t  f r e q u e n t l y excess f e r t i l i z e r soil  acidification  (Kowalenko  i s applied, p o t e n t i a l l y causing 1986),  environmental p o l l u t i o n  (Kohut, L e i b s c h e r , p e r s o n a l communications A g r i c u l t u r e Canada:Agassiz  1986),  with C.G.Kowalenko,  and wasted money; l e s s o f t e n ,  i n s u f f i c i e n t a p p l i c a t i o n s a r e made, these can cause a l o s s i n p o t e n t i a l crop y i e l d . Winter p r e c i p i t a t i o n Vancouver LFV  (Oct.- Mar.)  International Airport,  averages 815mm a t  t h e most Western  (Table 1), and annual p r e c i p i t a t i o n a c r o s s t h e r e g i o n  from 1,000mm t o 1,500mm, 75% o f t h i s f a l l i n g shows t h e annual water balance o f t h e LFV. the  point o f the  high w i n t e r r a i n f a l l  ranges  over winter. F i g . 1 As a consequence o f  i n t h e LFV i t was g e n e r a l l y assumed  that minimal c a r r y - o v e r o f r e s i d u a l N o c c u r r e d season t o season, hence s o i l  t e s t i n g f o r N, as used i n o t h e r p a r t s o f B.C., was  considered inappropriate.  Recent s t u d i e s however, have shown  a p p r e c i a b l e q u a n t i t i e s o f m i n e r a l N i n LFV s o i l s a t t h e s t a r t o f the  growing season  ( G u t h r i e and Bomke 1980;  Khan 1986).  For  example, Khan (1986) found 99 kg ha" i n t h e t o p 90cm o f a 1  p r e v i o u s l y unmanured LFV s o i l  i n May 1983.  At t h e same time,  Table 1. Precipitation and temperature summaries Oct.1983 - Sept.1985. Vancouver International Airport. (Monthly Means)  Month  Precipitation (urn) 1983-84 1984-85 30Yr.Av.  Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep  89.9 350.8 83.9 223.9 177.6 128.6 124.2 111.1 69.0 3.9 15.7 41.6  129.5 237.2 159.6 28.2 93.1 101.9 80.6 44.1 31.8 TR 31.5 59.1  122.2 141.2 165.4 147.3 116.6 93.7 61.0 47.5 45.2 29.7 37.1 61.2  Air Temperature (°C) 1983-84 1984-85 9.5 7.6 0.7 4.4 6.2 7.9 8.8 11.3 14.7 17.2 17.6 13.9  5.6 3.2 -2.2 I3.3 5.2 8.5 12.2 15.1 19.3 17.0 13.1 5  30Yr.Av 10.1 6.1 3.8 2.4 4.4 5.8 8.9 12.4 15.3 17.4 17.1 14.2  FRASER  VALLEY WATER  BALANCE  160  80  mm -i month  STORAGE  J  F  M  A  drainage  M  J  J  A  S  O  N  D  irrigation  F i c j u r e 1. A n n u a l w a t e r b a l a n c e (From H a r e and Thomas  o f t n e Lower F r a s e r V a l l e y . 1974)  144  kg ha"  t ha"  1  1  N was found i n a s i m i l a r depth o f s o i l t o which 120  p i g manure had been a p p l i e d i n 1982.  s i m i l a r f i n d i n g s by M e i s i n g e r even i n humid r e g i o n s fertilizer  soil  Such r e s u l t s , plus  (1982) i n Maryland, suggest that  m i n e r a l N should be i n c l u d e d i n  recommendations.  In h i s r e c e n t  evaluation  o f N use  i n B.C., Kowalenko (1986), concluded t h a t N a p p l i c a t i o n s i n the LFV  a r e c u r r e n t l y c l o s e to, or exceeding, t h e maximum  recommended, e s p e c i a l l y when manure i s i n c l u d e d . he s t r e s s e d  t h a t the r e s e a r c h  Furthermore,  data on s o i l N i n t h i s r e g i o n i s  at present inadequate f o r improving N f e r t i l i z e r recommendations.  1.2 OBJECTIVES In order t o improve t h e p r e c i s i o n of c u r r e n t  N fertilizer  recommendations i n the LFV, t h i s study was s e t up with t h e following  objectives:  1. To monitor s o i l 2.  m i n e r a l N changes during  the spring.  To i d e n t i f y the N requirement f o r corn on a s p e c i f i c and  site  i n v e s t i g a t e y i e l d response and N uptake e f f i c i e n c y a t  f o u r r a t e s o f a p p l i e d N. 3.  To compare p r e p l a n t  versus s i d e d r e s s  4. To determine the N s u p p l y i n g and  applied  c a p a c i t i e s o f some LFV s o i l s  r e l a t e these t o other s o i l p r o p e r t i e s ,  c r o p p i n g and crop response.  urea.  previous  2.LITERATURE REVIEW  2.1 THE NITROGEN REQUIREMENT EQUATION  N Requirement = e  t  (N s u p p l i e d by t h e s o i l ) +  e  e  (N p r o v i d e d by f e r t i l i z e r and/or manure)  (e = e f f i c i e n c y f a c t o r f o r N uptake)  T h i s equation r e p r e s e n t s the most extreme s i m p l i f i c a t i o n o f the N requirement  components f o r a non-leguminous crop. The  f o l l o w i n g d i s c u s s i o n w i l l expand on these components  i n order t o  o u t l i n e the f a c t o r s i n v o l v e d i n t h e improvment o f N recommendations i n the F r a s e r V a l l e y .  2.1.1  THE NITROGEN REQUIREMENT  The N requirement  f o r a s p e c i f i c crop i s determined  demand o f t h a t crop and t h e y i e l d o b j e c t i v e .  by the N  The N demand  v a r i e s g r e a t l y with s p e c i e s , s u b s t a n t i a l l y l a r g e r N c o n t e n t s a r e found i n f o r a g e s than i n r e p r e s e n t a t i v e y i e l d s o f c e r e a l (Table 2.1).  The y i e l d o b j e c t i v e ,  or 'Target Y i e l d ' ,  crops  i s derived  by one o f many pathways, r a n g i n g from pure 'seat of the pants' guesswork o r experience,  t o s o p h i s t i c a t e d computer modelling.  The most r e c e n t t r e n d f o r the d e t e r m i n a t i o n o f t h i s  yield  o b j e c t i v e i s t h e use o f t h e 'Maximum economic y i e l d ' (MEY) philosophy,  ( T i s d a l e e t a l . 1985).  T h i s i s simply t h e y i e l d  7  Table 2.1 A p p r o x i m a t e t o t a l N c o n t e n t and d i s t r i b u t i o n i n good y i e l d s o f some major c r o p s . From O l s o n and K u r t z (1982) and B e t t e r C r o p s ( 1 9 7 9 ) .  Crop  Plant Parts  Corn ( S i l a g e )  Grain  C o r n (Sweet)  Stover Grain Stover  Potatoes  (Irish)  Wheat Peas Alfalfa Orchard g r a s s / Perennial ryegrass  Tubers Vines Grain Straw Whole pods Vines T o t a l forage Total  forage  %N  Dry Y i e l d k g ha"'  1.5 0.9 2.2 1.2  10,000  0.3 2.3 2.0 0.8 0.9  56,000 5,000 5,400 6,000 1,100 6,800  1.1 2.8 2.2  9,000 4,100 5,500  18,000 12,700  Total N kg h a ' 150 80 90 65 170 115 110 45 100 80 510 280  which g i v e s the h i g h e s t  p o s s i b l e net r e t u r n per hectare.  It i s  a s p e c i f i c p o i n t on the y i e l d curve which i s u s u a l l y w i t h i n 5 10%  of the maximum, the p r o d u c t i o n  inevitably  i n v o l v e s high  inputs,  of such high y i e l d s  especially fertilizer.  The  maximum economic y i e l d s are governed mainly by c l i m a t e and c o n d i t i o n s and  by water a v a i l a b i l i t y .  A t y p i c a l MEY  sweetcorn on a deep l o e s s w i l l probably be higher shallow  sandy s o i l  due  h o l d i n g c a p a c i t i e s and  r o o t i n g depths.  The  e x p e r t i s e i n growing the In order  required.  to reach  the t a r g e t y i e l d  THE  manpower  by the other  two  i e . the s o i l  N  and  SOIL  In comparison t o t a r g e t y i e l d s and  entity.  to finances,  N.  NITROGEN SUPPLIED BY  by a crop,  i s also dictated  a s p e c i f i c amount of N i s  components i n the N requirement equation,  2.1.2  water  crop.  T h i s requirement i s f i l l e d  fertilizer\manure  than on a  nutrient status, MEY  the N s u p p l i e d by the s o i l  the a s s o c i a t e d N r e q u i r e d i s an extremely  I r r e s p e c t i v e of whether the t o t a l s o i l  uncertain  N i s known,  amount of N a c t u a l l y a v a i l a b l e to the crop f o r uptake over growing season, i s d i f f i c u l t that,  i n c o n t r a s t t o other  a f f e c t e d by  soil  for  t o the d i f f e r e n t  by the farmer's l i m i t a t i o n s with r e s p e c t and  to  to predict.  macronutrients,  The  the the  reason f o r t h i s i s  soil  N i s more  b i o l o g i c a l p r o c e s s e s than by p h y s i c a l and  chemical  reactions. S o i l N i s considered  t o be comprised of 2 main components:  an i n o r g a n i c component composed mainly of r e s i d u a l N0»-N, and  an  9 o r g a n i c component which i s m i n e r a l i z e d throughout the growing season.  95% or more of the N i n s u r f a c e s o i l s u s u a l l y occurs i n  the o r g a n i c form  (Stevenson  1982), and  i n most temperate  a g r i c u l t u r a l r e g i o n s the t o t a l N c o n c e n t r a t i o n i n the top 20cm v a r i e s between 0.03  and  0.4*/. ( T i s d a l e e t a l . 1985).  The  organic  N i s d i r e c t l y r e l a t e d t o s o i l o r g a n i c matter which i s approximately  5% N.  In the LFV  o r g a n i c matter l e v e l s g e n e r a l l y  range from 0-10%, however t h e r e are a few which can c o n t a i n much higher l e v e l s .  Some r e s e a r c h e r s  soils  S o i l o r g a n i c matter  l e v e l s depend on the h i s t o r y of the s o i l , management p r a c t i c e s , and  areas of peaty  the  previous  the c l i m a t e of the r e g i o n .  (Jansson  and Persson  1984)  consider  o r g a n i c component to be comprised of f o u r i n t e r c o n n e c t e d  the phases:  a) The  living  b) The  f r e s h or r e c e n t o r g a n i c d e b r i s , making up the  called  biomass,  ' A c t i v e phase' o f s o i l o r g a n i c N,  c) A 'Passive phase', comprising  very o l d m a t e r i a l which  i s r e s i s t a n t t o m i c r o b i a l breakdown, d) The  so-  phase which Paul and  and  Juma (1981) d e f i n e as  ' S t a b i l i z e d N' which has a h a l f - l i f e somewhere between the a c t i v e and Broadbent  passive  fractions.  (1984) s t a t e d t h a t many s o i l t e s t i n g  procedures  attempt to determine the s i z e of the a c t i v e phase which i s then taken t o r e p r e s e n t p o t e n t i a l l y a v a i l a b l e N. The  i n o r g a n i c component of s o i l  N d e r i v e s e i t h e r from  m i n e r a l i z a t i o n of the o r g a n i c p o r t i o n or from r e s i d u a l fertilizer  remaining  from the p r e v i o u s crop.  The  amount of  r e s i d u a l N at the b e g i n n i n g of a f i e l d  season can  be r e a d i l y  measured, i t depends upon the e f f i c i e n c y of uptake of the crop,  the f e r t i l i z e r  leaching  requirement o f t h a t crop,  or d e n i t r i f i c a t i o n t h a t has  occurred  and  last  the amount of  between  cropping  seasons. The  amount o f o r g a n i c  N mineralized  over the growing season  i s a component of the N requirement which can  only  be  estimated.  M i n e r a l i z a t i o n r a t e depends h e a v i l y on s o i l c o n d i t i o n s , pH,  0 , e  moisture, and  summer weather which  i n v a r i a b l y changes from year t o year i n the LFV. N mineralized  pea  The  amount of  a l s o depends on the nature of the  phase such as the type of r e s i d u e s e.g.  l e f t by the p r e v i o u s  the N i n i t s i n o r g a n i c  form,  3  i n the humid LFV  due  particularly  N0 -N, i s extremely s u s c e p t i b l e t o l o s s , e s p e c i a l l y by region  of B.C..  may  occur i n the LFV  wet  and  anaerobic.  The  amount of mineral  denitrification,  because the s o i l  necessarily directly  leaching  Other p o t e n t i a l s o u r c e s of N  l o s s are ammonia v o l a t i l i z a t i o n and  'ei'  crop;  ratio.  Once m i n e r a l i z e d ,  not  active  v i n e s are more e a s i l y decomposed than wheat stubble,  t o t h e i r lower C/N  as  temperature; thus m i n e r a l i z a t i o n i s  l a r g e l y i n f l u e n c e d by the s p r i n g and  organic  such  the  i n spring i s often  N a v a i l a b l e f o r use  latter very  by the p l a n t i s  r e l a t e d to the amount i n the s o i l .  The  v a l u e i n the N Requirement e q u a t i o n r e l a t e s the amount of N  found i n the s o i l  t o the amount taken up by the crop.  v a l u e v a r i e s between c r o p s and management c o n d i t i o n s .  This  between s o i l s under d i f f e r e n t  For example, a crop such as sweet  corn  11 has  a lower N requirement than s i l a g e corn and consequently  would 'suck up' l e s s N from t h e s o i l and hence p o s s i b l y cause a lower e  t  value.  Similarly, a s o i l  with a compacted l a y e r may  prevent normal r o o t e x p l o r a t i o n and thus l i m i t crop uptake o f s o i l N again  2.1.3  lowering  the e  t  value.  NITROGEN SUPPLIED BY MANURE AND FERTILIZER  'N S u p p l i e d  by Manure and F e r t i l i z e r ' i s e s s e n t i a l l y t h e  d i f f e r e n c e between the 'N Requirement' and t h e 'N s u p p l i e d by the s o i l ' .  However, t h i s component o f t h e N Requirement  Equation was a l s o preceded by an e f f i c i e n c y f a c t o r , "ee", which i n t h i s case stands f o r an e s t i m a t e o f t h e p r o p o r t i o n  o f 'added'  N which i s a c t u a l l y a v a i l a b l e and taken up by t h e p l a n t . t r a n s f e r from added N t o p l a n t i n c o r p o r a t e d mineralization, transformations,  The  N, l i k e  i s a function of several interacting N however i t i s a l s o dependent on s e v e r a l  management v a r i a b l e s , such as N source, placement and t i m i n g . One  o f t h e main f a c t o r s a f f e c t i n g t h e e f f i c i e n c y value ( e ) e  i s t h e type o f N added. fertilizer  There a r e many d i f f e r e n t k i n d s o f N  and t h i s i s not t h e p l a c e t o l i s t these,  however t h e  major d i f f e r e n c e i n t h e i r e f f i c i e n c y i s t h e form i n which t h e N i s present, fertilizer),  i . e . farm produced o r manufactured organic  or inorganic,  (e.g. manure o r N  N0 -N o r NH -N o r both. 3  4  Two o f t h e d i f f e r e n c e s a f f e c t i n g t h e e f f i c i e n c y o f N a p p l i e d as manure and N a p p l i e d as f e r t i l i z e r of N i n t h e manure b e f o r e varying,  are,  1) t h e dynamic s t a t e  i t even reaches t h e f i e l d ,  and g e n e r a l l y u n c o n t r o l l e d  and 2) t h e  amounts o f s o l i d matter and  12  water c o n t a i n e d a f f e c t s the e  8  i n t h e manure.  The method o f a p p l i c a t i o n  value f o r manure even more than f o r N f e r t i l i z e r .  S i n c e many o f t h e N forms i n manure a r e r a p i d l y converted  t o NH  a  a s i g n i f i c a n t p o r t i o n o f t h e N i n manure can be l o s t t o the atmosphere depending on the spreading, techniques.  h a n d l i n g and s t o r a g e  Vanderholm (1975) and G i l b e r t s o n e t a l .  (1979)  r e p o r t e d NH -N l o s s e s o f 10-99% and 10-75% r e s p e c t i v e l y , 4  depending on types o f manure management and treatment systems. Thus the farmer i s g e n e r a l l y u n c e r t a i n o f the amount o f N he o b t a i n s from h i s manure a p p l i c a t i o n s and o f t e n makes no allowances f o r t h i s i n p u t when c a l c u l a t i n g h i s N f e r t i l i z e r requirements.  This uncertainty  with an i n c r e a s e d adoption  should soon d i m i n i s h however  of the r e c e n t l y published  'Manure  Management G u i d e l i n e s ' ( B e r t r a n d and B u l l e y 1985) based on the manure management s i m u l a t i o n model developed by B u l l e y and Cappelaere ( 1 9 7 8 ) . When manure i s a p p l i e d , about h a l f the N i s u s u a l l y as NH -N the remainder being 4  Organic  i n o r g a n i c forms (Khan 1986).  forms o f N i n e i t h e r manure o r f e r t i l i z e r  d i r e c t l y by t h e p l a n t  (with the e x c e p t i o n  a r e not used  of f o l i a r  urea), however when the o r g a n i c forms a r e converted NOj-N t h e N becomes r a p i d l y a v a i l a b l e f o r uptake. C0(NH >e, s  a synthetic organic f e r t i l i z e r  major source  urea  and f i n a l l y  applied t o NH -N and 4  Urea,  which i s becoming the  o f a p p l i e d N i n North America and Western Europe  was the f e r t i l i z e r soil,  present  used i n t h i s study.  i s converted t o N0 -N. a  On a p p l i c a t i o n t o the  f i r s t t o H NC00NH , then t o 2NH e  4  The i n i t i a l t r a n s f o r m a t i o n  t o NH  3  4  + C0 is  a  c a t a l y z e d by t h e h y d r o l y t i c enzyme urease and proceeds r a p i d l y under f a v o u r a b l e  c o n d i t i o n s o f temperature, moisture and pH.  P l a n t s can take up i n o r g a n i c N as both NH*-N and N0 -N 3  although some c r o p s p r e f e r one form o r t h e other. theory,  farmers should  highest  e  8  Thus i n  choose t h e N source which produces t h e  value f o r t h e i r s o i l c o n d i t i o n s .  N0 -N i s f a r more 3  mobile i n t h e s o i l than NH*-N, hence i t i s l e s s s u i t a b l e f o r use under wet,  leaching conditions,  conducive t o n i t r i f i c a t i o n , N.  however where t h e environment i s  NH*-N i s r a p i d l y transformed t o N0 3  In p r a c t i c e , t h e c h o i c e o f f e r t i l i z e r  on t h e b a s i s o f f a c t o r s such as c u r r e n t The  reason f o r t h e i n c r e a s e d  i s most f r e q u e n t l y made p r i c e and a v a i l a b i l i t y .  p o p u l a r i t y o f urea i s i t s  r e l a t i v e l y low c o s t and high N c o n c e n t r a t i o n ,  a l s o t h e uniform  p r i l l s a r e easy t o t r a n s p o r t and spread evenly order  t o ensure a high e  value  8  p r a c t i c e s must be a p p l i e d .  In  f o r urea good management  A f t e r a p p l i c a t i o n urea i s h i g h l y  s u s c e p t i b l e t o v o l a t i l i z a t i o n and t o l e a c h i n g . should  on a f i e l d .  I d e a l l y , urea  be a p p l i e d t o a depth o f 5 cm o r washed t o t h i s depth  w i t h i n 3-6 days a f t e r f e r t i l i z a t i o n  ( T i s d a l e e t a l . 1985).  I t i s not p o s s i b l e t o p r e d i c t e« from f i r s t  principles,  the  problem t h e r e f o r e has g e n e r a l l y been approached e m p i r i c a l l y by estimating  fertilizer  climatic conditions.  e f f i c i e n c i e s over a range o f s o i l and Most l i t e r a t u r e v a l u e s e s t i m a t e e  manufactured f e r t i l i z e r 1973;  Hauck 1984;  for  N t o be between 50 and 70% ( S t a n f o r d  Boswell e t a l . 1986).  In s p i t e o f knowing e , t h e c r u c i a l q u e s t i o n s  ie.  a  "How much a d d i t i o n a l N i s needed t o f i l l  still  remains,  t h e N Requirement  under s p e c i f i e d f i e l d c o n d i t i o n s ? " . approaches taken t o t h i s q u e s t i o n world over t h e past century;  There have been many  i n d i f f e r e n t parts of the  the following s e c t i o n o u t l i n e s a  few  o f these which may be r e l e v a n t t o a humid r e g i o n such as t h e  LFV  and a l s o p r o v i d e s  a background t o t h e approach used i n the  project.  2.2 NITROGEN FERTILIZER RECOMMENDATIONS IN HUMID REGIONS  Many o f t h e methods proposed f o r making N f e r t i l i z e r p r e d i c t i o n s have r e c e n t l y been d i s c u s s e d  and c r i t i q u e d i n  reviews by Jungk and Wehrmann (1978), S t a n f o r d  (1982), Keeney  (1982), and Meisinger  i n t o f o u r main  (1984); t h e methods f a l l  categories: 1) P l a n t 2) S o i l  Analysis Sampling  3) S o i l N Index Systems 4) Computer  2. 2. 1  Modelling  PLANT ANALYSIS  Plant analysis f o r N f e r t i l i z e r i n v o l v e s t a k i n g a sap, l e a f ,  o r whole p l a n t sample from t h e crop  once, o r a number o f times, d u r i n g 1984) .  recommendations g e n e r a l l y  The sample i s analysed  t h e growing season (FAO  f o r t o t a l N (Moller  Nielsen  1985) , i n o r g a n i c N ( S c a i f e and Bray 1977; Wehrmann e t a l . 1982) or N - a s s o c i a t e d  pigments, such as c h l o r o p h y l l and c a r o t e n o i d s  15 ( O ' N e i l l e t a l . 1983).  Another method o f p l a n t a n a l y s i s i s t h e  n o n - d e s t r u c t i v e use o f s t a n d a r d l e a f c o l o u r c h a r t s being used i n Japan  (Yazawa 1977).  R e n o t a t i o n System  The c h a r t s are based on t h e Munsell  with t h e a i d o f a c o l o u r d i f f e r e n c e  meter.  P l a n t a n a l y s i s cannot be used t o determine b a s a l N applications, symptoms.  i t s main use i s t o r e v e a l and c o n f i r m d e f i c i e n c y  I f a N d e f i c i e n c y becomes v i s u a l ,  crop N a p p l i c a t i o n s  w i l l probably be t o o l a t e t o prevent a t l e a s t some y i e l d Thus r e g u l a r p l a n t sampling must be used t o d e t e c t  loss.  potential  d e f i c i e n c i e s and a l s o s u b c l i n i c a l d e f i c i e n c i e s which may be caused by a r e d u c t i o n i n m i n e r a l supply, eg. waterlogging, s o i l drying,  leaching,  low temperatures, o r by a h i g h N demand  r e s u l t i n g from p a r t i c u l a r l y good growing S c a i f e and Bray  conditions.  (1977) o u t l i n e d t h e importance o f f r e q u e n t  p l a n t sampling and developed a 'Quick Sap T e s t ' which  could  e a s i l y be used by farmers i f r e f i n e d and manufactured. used  'Merckoquant'  chemicals i n 1976. to  The t e s t  t e s t s t r i p s i n t r o d u c e d i n t o t h e UK by BDH These a r e t h i n p l a s t i c s t r i p s ,  which a r e a t t a c h e d two squares o f white f i l t e r  75mm x 5mm, paper  impregnated with an aromatic amine and N - ( l n a p t h y l ) e t h y l e n e diamine.  Both squares t u r n v i o l e t when wetted with a N0 -N  solution,  and one o f them c o n t a i n s a r e d u c i n g agent and hence  e  t u r n s v i o l e t with NO,-N.  Colour standards representing  0,10,30,100,250 and 500 mg k g " N0 1  3  < =0, 2, 7, 23, 56, 113,  N) a r e p r i n t e d on t h e tube c o n t a i n i n g t h e s t r i p s . Merckoquant  mg k g "  1  Because t h e  s t r i p s were not i n t e n d e d f o r p l a n t sap a n a l y s i s ,  S c a i f e and Bray (1977) found t h a t t h e s t a n d a r d c o l o u r s d i d not  16 extend 1000  as h i g h as the optimum v a l u e In most young p l a n t s (about  mg kg "  stress,  1  N0»-N).  N e v e r t h e l e s s , when p l a n t s s u f f e r e d N  t h e i r sap N0 -N l e v e l s , 3  p a r t i c u l a r l y i n the  lower  l e a v e s , soon f e l l t o l e v e l s w i t h i n the range covered by strips.  the  Other r a p i d methods f o r determining n i t r a t e i n p l a n t s  are c u r r e n t l y i n use i n C a l i f o r n i a ,  (Rauschkolb  and Brown  1974)  and West Germany, (Wehrmann et a l . 1982). The i s based  i n t e r p r e t a t i o n o f p l a n t a n a l y s e s f o r N recommendations on the concept  t h a t the N content i n the p l a n t w i l l  r e f l e c t N a v a i l a b i l i t y i n the s o i l .  In p r i n c i p l e t h i s  concept  i s sound, because N present i n the p l a n t must o r i g i n a l l y have been a v a i l a b l e i n the s o i l  (with the e x c e p t i o n of f o l i a r N  a p p l i c a t i o n s and N f i x e d by legumes).  O ' N e i l l et  al.(1983)  showed t h a t a n a l y s i s o f s p r i n g b a r l e y , as e a r l y as t h r e e weeks a f t e r emergence, was  an e f f e c t i v e assessment of s o i l N s t a t u s .  However, the N content i n the p l a n t not o n l y depends on N a v a i l a b i l i t y i n the s o i l but a l s o on f a c t o r s such as growth rate, t o x i c i t y levels, i n the s o i l and p l a n t .  and the c o n c e n t r a t i o n s of o t h e r n u t r i e n t s Consequently,  two  approaches have been  used f o r i n t e r p r e t i n g p l a n t a n a l y s e s f o r N; 1) The Value' approach (Barber 1984). 2) The  'Diagnosis  Recommendation I n t e g r a t e d System' (DRIS) approach, Sumner  'Critical  and proposed  by  (1977).  The c r i t i c a l value approach has been widely used. p l a n t p a r t s are analyzed f o r N i n experiments due t o N f e r t i l i z a t i o n . vs. y i e l d ,  P l a n t s or  where y i e l d  varies  A p l o t i s made of the N c o n c e n t r a t i o n  and from t h i s a c r i t i c a l value i s obtained.  The  17 critical  value  i s the p l a n t N content above which y i e l d no  increases s i g n i f i c a n t l y .  Above the c r i t i c a l  value t h e r e  range which i n d i c a t e s t h a t the N l e v e l i s adequate. nutrient concentration depression  longer  is a  When  i n c r e a s e s above a c e r t a i n l e v e l ,  yield  may occur i n some c r o p s due t o excess n u t r i e n t s .  One  o f the problems i n using t h i s method i s t h a t when a n u t r i e n t other  than N r e s t r i c t s y i e l d s ,  disproportionately  the N content i n the p l a n t may be  high.  In the DRIS approach, a l l f a c t o r s t h a t can be measured and t h a t have an a f f e c t on y i e l d ,  a r e measured.  The components of  y i e l d a r e c h a r a c t e r i z e d i n terms o f i n d i c e s , a l l o w i n g f a c t o r s t o be c l a s s i f i e d  i n order  o f l i m i t i n g importance.  the concept o f 'Balance o f N u t r i e n t s ' i s i n c o r p o r a t e d system.  the y i e l d Thus  i n t o the  The main l i m i t a t i o n t o t h i s approach i s i n o b t a i n i n g a  r e l i a b l e index f o r each n u t r i e n t f o r h i g h - y i e l d i n g p l a n t s and i n measuring f a c t o r s other Nevertheless, critical  than n u t r i e n t s t h a t l i m i t  yield.  the DRIS approach i s an improvement over  using  values.  The major drawback t o p l a n t a n a l y s i s i s t h a t t i s s u e t e s t i n g i s most r e l i a b l e when the crop i s w e l l developed. point,  e. g. f o r corn a t s i l k i n g ,  r e q u i r e d t o apply  the s p e c i a l i z e d equipment  N i s g e n e r a l l y t o o c o s t l y t o make the  f e r t i l i z e r a p p l i c a t i o n worthwhile. c u r r e n t l y being  At t h i s  However p l a n t a n a l y s i s i s  used f o r some p e r e n n i a l crops,  and  f o r most t r e e crops.  al.  (1983) with s p r i n g b a r l e y ,  such as cotton,  The promising r e s u l t s o f O ' N e i l l et and M o l l e r N i e l s e n  (1985) i n  Denmark and Wehrmann e t a l . (1982) i n West Germany with winter  18 wheat, suggest t h a t p l a n t a n a l y s i s may be important i n improving N fertilizer growing  use e f f i c i e n c y ,  p a r t i c u l a r l y i n regions intensively  one major crop.  2.2.2 SOIL SAMPLING Although e v a l u a t i n g a v a i l a b l e N through s o i l m i n e r a l N c o n t e n t s was c o n s i d e r e d t o be o f l i m i t e d v a l u e as r e c e n t l y as 1965  (Bremner 1965) i t i s now a common p r a c t i c e i n many p a r t s o f  Western Europe and North America  ( M e i s i n g e r 1984).  Residual  i n o r g a n i c N i n t h e r o o t zone i s approximately e q u i v a l e n t i n a v a i l a b i l i t y to f e r t i l i z e r  N (Keeney 1982),  consequently  soil  sampling f o r r e s i d u a l NQ»-N i s a r o u t i n e p r a c t i c e i n areas where winter l e a c h i n g i s s m a l l , a f t e r summer f a l l o w , and a f t e r heavy N applications.  Table 2.2 shows t h a t N0»-N e v a l u a t i o n s a r e  c u r r e n t l y used f o r N f e r t i l i z e r  recommendations i n most o f the  Western s t a t e s o f t h e U.S.A., they a r e a l s o commonplace i n t h e P r a i r i e P r o v i n c e s o f Canada, t h e Peace Region o f B. C. and many p a r t s o f Western Europe (Netherlands: Kolenbrander e t a l . 1981; Neeteson al.  1982; Neeteson  and Smilde 1983; Neeteson  1981. Belgium: Boon 1981. Germany: Wehrmann and Scharpf  1979; In  Wehrmann e t a l . 1982. Denmark: Ostergaard  1982).  s e m i a r i d areas, where e x t e n s i v e l e a c h i n g and  d e n i t r i f i c a t i o n do not occur b e f o r e p l a n t i n g , o f t e n performed  i n the f a l l .  s o i l sampling i s  S t u d i e s i n these areas have shown  s t r o n g r e l a t i o n s h i p s between f a l l In  1985; R i s e t  N0 -N and crop requirements. 3  semihumid areas, s o i l sampling i s g e n e r a l l y performed  i n the  s p r i n g and i s d i r e c t e d more towards e s t i m a t i n g m i n e r a l i z e d N  19  Table 2.2  -  --  General summary of current s o i l N evaluation systems i n various regions of the Doited States. (Adapted from Meisinger 1984) ••-  Average N credits N factor for crop yield goal  Region-states included  Soils data commonly solicited  Crop  Avg value  Soil N evaluation Inorganic  Manure  Mineralization  kg N t"'  Legumes Soybeans  kg N t"'  Alfalfa  kg N ha  -t  Northeast Conn,NY,Pa  Soil type, drainage  Com (grain)  24.5  None  Based on s o i l type in one state  2.3  NA  150  Soil type, texture. drainage  Corn (grain)  24.9  None  None  3.0  18  80  Geographic area. s o i l type  Com (grain)  26.4  None  None  NA  30  55  Soil type,texture. drainage. geographic area  Com (grain)  26.2  One state tests for  Based an total N and s o i l texture i n one state  2.4  32  100  Com Soil type, drainage. (grain) geographic area Wheat  29.8 NOj-N  Two states use total N and fixed Mineralization rates  2.4  36  90  Mid-Atlantic Del,Ky,Md, NJ,Va,WVa Southeast Ga,NC,Miss,SC Midwest 111,Ind,Iowa, Mich,Minn,Mo West Colo,Kan,Neb, ND,SD  40.5  Southwest Ariz,Okla,Tex  Soil association. topographic area. texture  Wheat  41.4  N0 -N  None  NA  NA  90  Soil type .drainage. geographic area  Wheat  46.2  N0,-N  A region within one state uses aerobic mineralization  NA  NA  NA  3  Northwest Mont,Ore, Wash,Idaho  NA refers to inadequate data  or infrequently used i n area.  than r e s i d u a l N, except where c o n d i t i o n s f a v o u r i n g N r e t e n t i o n prevail,  eg. deep s o i l s or l a r g e p r e v i o u s N i n p u t s .  Bomke ( P e r s o n a l communication 1986)  In the LFV,  sampling s o i l s on Westham  I s l a n d B. C. c o n s i s t e n t l y found minimal amounts of N0 -N i n the 3  plough l a y e r i n January.  However Khan (1986), and G u t h r i e and  Bomke (1980) a l l found some m i n e r a l N i n Hay mainly i n the 3060cm depth.  I t i s p o s s i b l e t h a t N0 -N found i n the s u r f a c e 3  h o r i z o n s i n s p r i n g i s due t o m i n e r a l i z a t i o n ,  and N0 -N found at 3  depth i s r e s i d u a l N from the p r e v i o u s c r o p p i n g season which has been washed down the p r o f i l e d u r i n g winter. The o b j e c t i v e o f a l l s o i l sampling, fall,  i s t o o b t a i n an e s t i m a t e of the s o i l N a v a i l a b l e t o the  plant. first  whether i n s p r i n g or  There are two approaches where N f e r t i l i z e r  t o making t h i s estimate, the  recommendations are made s o l e l y on the  b a s i s of r e s i d u a l s o i l N0 -N, and the second, 3  where  recommendations are made on the b a s i s of two components; a) a measure of m i n e r a l N i n the s o i l p r o f i l e on a s p e c i f i c date and b) an e s t i m a t e of N m i n e r a l i z e d over the growing  season.  most cases, e s p e c i a l l y i n semihumid areas, the two approach approach,  i s c o n s i d e r a b l y more a c c u r a t e . the f i r s t  than the second.  In  component  In t h i s two  component  component i s somewhat s i m p l e r t o determine  M i n e r a l N measurements j u s t r e q u i r e a c c u r a t e  and p r e c i s e chemical a n a l y s e s and the c o l l e c t i o n of a r e p r e s e n t a t i v e s o i l sample.  In c o n t r a s t , e s t i m a t e s of  mineralization for f e r t i l i z e r  recommendations must be a b l e t o  g i v e an a c c u r a t e p r e d i c t i o n of the amount of N becoming a v a i l a b l e over the growing  season and must a l s o be simple,  rapid  21 and r e p r o d u c i b l e , and not a f f e c t e d by sample pretreatment.  MINERAL NITROGEN MEASUREMENTS Chemical a n a l y s e s f o r m i n e r a l N present no major problems s i n c e t h i s component o f a v a i l a b l e N i s g e n e r a l l y measured i n the form o f NO,-N o r NH*-N which can be e a s i l y e x t r a c t e d with v a r i o u s s a l t s o l u t i o n s and i s r e a d i l y equipment  analyzed with modern  (Bremner 1965; Jackson e t al.1975).  The major  problem  with m i n e r a l N d e t e r m i n a t i o n i s t h e c o l l e c t i o n o f a r e p r e s e n t a t i v e s o i l sample, t h i s i s due mainly t o s o i l  N0 -N 3  v a r i a b i l i t y but a l s o t o sample p r e p a r a t i o n and economic limitations  on s o i l  sampling.  S o i l v a r i a b i l i t y i s m u l t i d i m e n s i o n a l and i n v o l v e s  spatial  components i n t h e h o r i z o n t a l and v e r t i c a l d i r e c t i o n s as w e l l as temporal components.  The v a r i a b i l i t y stems from; a) the  s o l u b i l i t y and m o b i l i t y o f N0 -N, b) t h e nonuniform 3  of N, (e.g s i d e d r e s s i n g ,  manure), c) the n a t u r a l  application  spatial  h e t e r o g e n e i t y o f s o i l o r g a n i c matter and s o i l water,  and d) t h e  s p a t i a l and temporal h e t e r o g e n e i t y o f s o i l N t r a n s f o r m a t i o n s such as l e a c h i n g ,  d e n i t r i f i c a t i o n , and i m m o b i l i z a t i o n .  The v a r i a b i l i t y o f s o i l m i n e r a l N i n f l u e n c e s t h e time o f sampling,  t h e sampling depth and t h e number o f samples t h a t must  be taken f o r a r e p r e s e n t a t i v e s o i l sample. Stanford  (1982) i n t h e i r reviews o f s o i l sampling methods  recommend sampling as c l o s e t o f e r t i l i z i n g alternatively rainfall.  Ward (1971) and  time as p o s s i b l e , or  i n t h e l a t e autumn i n areas o f low winter  M i n i m i z i n g t h e time between sampling and f e r t i l i z i n g  22 w i l l minimize the e f f e c t s o f weather on the s o i l N and thus i n c r e a s e the accuracy o f recommendations.  Sampling must be done  each year f o r m i n e r a l N d e t e r m i n a t i o n s .  Recommended depth of  sampling v a r i e s from 30cm (Nyborg et al.1976; Onken and Sunderman 1972;  Magdoff e t a l . 1984) t o anything as deep as  180cm (Dahnke and Vasey 1973).  MoBt recommendations  are e i t h e r  60cm or 100cm, normally depending on the r o o t i n g depth o f the crop but sometimes m o d i f i e d by the presence o f an impeding layer  (Carter et a l .  1976), or o t h e r p r e v a i l i n g s o i l  such as moisture d i s t r i b u t i o n available N status.  (Meisinger 1984)  to  c o s t o f sampling.  conditions  and s u r f a c e  however deeper samples add t o  A number o f s t u d i e s have shown t h a t N0 -N 3  depth can sometimes be e s t i m a t e d from s h a l l o w e r s o i l  ( S t a n f o r d 1982).  soil  Plough depth sampling i s i n most cases  inadequate due t o N0»-N m o b i l i t y , the  soil  samples  L o c a l e x p e r i m e n t a t i o n over s e v e r a l years i s  r e q u i r e d t o determine the minimum sampling depth f o r a given soil-crop-climate condition. Common s o i l sampling i n s t r u c t i o n s c a l l f o r a 10-20  core  composite from an area t h a t i s s e l e c t e d t o r e f l e c t s i m i l a r past management, topography, s o i l type, e t c . (Bole and Pittman Cameron e t a l . 1971; Reuss e t al.1977; Smith 1980).  1976;  This  sampling i n t e n s i t y e s t i m a t e s the mean N0 -N l e v e l t o 3  approximately +_ 20'/. i n about 75% of the area sampled, of  or t o  the mean i n about 90% o f the area (Meisinger 1984).  +25%  Without  an e x t e n s i v e s o i l sampling programme M e i s i n g e r (1984) b e l i e v e s i t q u i t e u n l i k e l y t h a t a f i e l d N0 -N mean can be e s t i m a t e d t o 3  b e t t e r than +_ 20% o f the mean.  As a consequence  of t h i s  spatial  23 variability,  both M e i s i n g e r (1984) and Kowalenko (1985) suggest  t h a t t h e problem to  can be l e s s e n e d i f t h e s o i l N0 -N t e s t i s used a  c l a s s i f y areas i n t o c a t e g o r i e s ,  such as, low, medium or high  s o i l NOj-N, r a t h e r than t r y i n g t o determine s p e c i f i c  levels.  ESTIMATING MINERALIZATION In  s p i t e o f t h e v a r i a b i l i t y problem  and the u n c e r t a i n t y  r e g a r d i n g t h e best time and depth a t which t o sample f o r a s p e c i f i c crop, measurements o f m i n e r a l N i n t h e p r o f i l e a r e i n v a r i a b l y more p r e c i s e than e s t i m a t e s o f m i n e r a l i z a t i o n .  The  amount o f m i n e r a l N made a v a i l a b l e by m i n e r a l i z a t i o n i s very difficult  to predict,  e s p e c i a l l y i n humid r e g i o n s ,  because  m i n e r a l i z a t i o n i s g r e a t l y dependent on environmental such as temperature growing to  season.  factors  and moisture which f l u c t u a t e over t h e  Consequently,  be i m p r e c i s e because  e s t i m a t e s o f m i n e r a l i z a t i o n tend  they e i t h e r ; a) t r y t o s i m u l a t e growing  season weather c o n d i t i o n s , or b) t r y t o p r o j e c t growing m i n e r a l i z a t i o n from e i t h e r term i n c u b a t i o n s .  season  'point v a l u e s ' o f s o i l N or s h o r t  The many approaches  used t o determine  m i n e r a l i z a t i o n have been reviewed on s e v e r a l o c c a s i o n s (Bremner 1965;  Dahnke and Vasey 1973; S t a n f o r d 1982; Keeney 1982) thus i t  i s not necessary t o examine these i n d e t a i l here. c o n s i d e r f i v e main  Most reviews  approaches:  i ) V e g e t a t i v e procedures.  These i n c l u d e both f i e l d and  greenhouse procedures which r e l a t e t o t a l dry matter y i e l d , N c o n c e n t r a t i o n o r p r e f e r a b l y t o t a l N uptake, ii)  M i c r o b i a l procedures.  t o s o i l N.  These i n v o l v e i n c u b a t i o n s o f s o i l  24 samples under temperature and m i n e r a l i z a t i o n and  water c o n d i t i o n s conducive t o  measure the t o t a l mineral  N produced a f t e r a  g i v e n time p e r i o d . iii)  T o t a l a n a l y s i s procedures.  These u s u a l l y e s t i m a t e  t o t a l N d i r e c t l y by a K j e l d a h l a n a l y s i s , or i n d i r e c t l y through a Walkley-Black o r g a n i c determined using  matter determination.  Mineral  N is  the assumption t h a t a f i x e d percentage of  total  N i s mineralized. iv)  Chemical e x t r a c t i o n procedures.  These s e p a r a t e a l l , or  p a r t of, the a c t i v e N pool u s i n g e x t r a c t i n g agents t h a t can g r e a t l y i n i n t e n s i t y , ranging n e u t r a l s a l t s or water.  from s t r o n g  a c i d s or bases to  D i f f e r e n t components of s o i l N  presumed t o c o n t r i b u t e more or l e s s t o m i n e r a l i z a b l e v) I n d i r e c t Procedures. the N s o i l sample, using experiments and  other  systems which use such an i n d i r e c t  information  sources.  N.  obtained  Many of the  from  field  recommendation  a s o i l sample, c a l c u l a t e m i n e r a l i z a t i o n  of the f i r s t  N and  r e s u l t s ; they are t h e r e f o r e u n d e s i r a b l e  in N  The  g e n e r a l l y the s t r o n g  f o r use  field  cause o f these poor c o r r e l a t i o n s i s i n f l u e n c e of growing season c l i m a t e  f i e l d m i n e r a l i z a t i o n and  i n some cases,  notably  the  t o the e f f e c t of sample pretreatment  Keeney 1982)  four  i s poor c o r r e l a t i o n between  l a b o r a t o r y or greenhouse i n d i c e s of m i n e r a l i z e d  1984,  by  procedure.  approaches have shown t h a t t h e r e  methods, due  are  These i n v o l v e e x t r a p o l a t i n g from  Most reviews of experiments u s i n g any  recommendations.  vary  or the presence of v a r y i n g  on  biological (Meisinger  amounts of  25 r e s i d u a l m i n e r a l N from p r e v i o u s f e r t i l i z a t i o n . the  Furthermore,  b i o l o g i c a l methods r e q u i r e a minimum o f a week f o r r e s u l t s  and would thus be u n s u i t a b l e f o r r a p i d recommendations, however if  they o n l y had t o be performed every few y e a r s they may have  some p o t e n t i a l .  Indeed C a r t e r e t al.(1974,1976)  and S t a n f o r d  (1977) showed i n two s t u d i e s t h a t use o f a m i n e r a l i z a b l e N index based on an i n c u b a t i o n , improve  i n c o n j u n c t i o n with p r o f i l e N0 -N, would 3  the p r e d i c t i o n of N f e r t i l i z e r  s o l e l y on t h e b a s i s o f p r o f i l e N0 -N. 3  needs above t h a t made These two experiments  however, used sugar beets i n a c a r e f u l l y managed crop environment  and i n a c l i m a t e where excess p r e c i p i t a t i o n d i d not  occur, t h e r e f o r e i t i s u n l i k e l y such r e s u l t s c o u l d be a p p l i e d t o the  Fraser  Valley.  SOIL SAMPLING METHODS USED I N WESTERN EUROPE Most o f t h e r e g i o n s t h a t use s o i l N0 -N sampling i n t h e i r 3  fertilizer  recommendations use some form o f i n d i r e c t method t o  e s t i m a t e m i n e r a l i z e d N, e i t h e r from t h e m i n e r a l N found on a s p e c i f i c date o r from o t h e r s o i l  f a c t o r s such as o r g a n i c matter,  manure, p r e v i o u s c r o p p i n g e t c . .  The methods which account f o r  m i n e r a l i z e d N from m i n e r a l N i n t h e p r o f i l e a r e most common i n Western  Europe,  Belgium  (e.g. Bakker e t a l . 1981; Boon 1981; Neeteson 1985;  Neeteson et  e t a l . 1984; Wehrmann and Scharpf 1979,1986; Wehrmann  al.,1982).  termed  n o t a b l y t h e Netherlands, West Germany and  The methods used i n these c o u n t r i e s ,  generally  *N«i„' methods, do not a c t u a l l y e s t i m a t e m i n e r a l i z a t i o n ,  i n s t e a d they determine t h e r e q u i r e d f e r t i l i z e r  rate  'N p', from 0  a knowledge o f t h e c r o p ' s f e r t i l i z e r r e s i d u a l N and t h e s o i l  N requirement  mineral N at f e r t i l i z i n g  years of large s c a l e f i e l d  experimentation,  a t zero  time.  After  c o n s i s t i n g o f many  s i t e s c o n t a i n i n g a range o f a p p l i e d N f e r t i l i z e r  levels,  r e l i a b l e recommendations have now been achieved f o r wheat, beet, p o t a t o e s and a number o f v e g e t a b l e crops,  sugar  (Wehrmann e t a l .  1982). For example, i n the Netherlands, sugar beet  (Neeteson  and Smilde,  regression l i n e relating s o i l  1983) i s based  mineral N (N«  winter p e r i o d (March) t o t h e optimum  N„p  Nop,  N„i„  tf>  on t h e  ) a t the end o f the  N fertilizer  rate  (N ): o p  = 220 - 1.7 N. , „  i n kg h a  and N o p i s based  the N recommendation f o r  - 1  N, sampling  on t h e y i e l d v a l u e  depth f o r N.,„ i s 60 cm, ( i n Df1) i r r e s p e c t i v e o f N  fertilizer  cost.  F o l l o w i n g green manures, 20-30 kg h a  fertilizer  a r e s u b t r a c t e d , and with bad s o i l  1 -  of  structure  a d d i t i o n a l N above t h e recommended dose i s suggested. For winter wheat i n West Germany, f u r t h e r r e f i n e m e n t s t o t h e Nop  t e c h n i q u e have been made u s i n g p l a n t sampling  al.  1982).  I f a rapid nitrate test,  performed  (Wehrmann e t  on wheat  stalk  segments a t t h e b o o t i n g stage, or a t e a r emergence, i n d i c a t e s a deficiency,  t o p d r e s s i n g i s performed.  summarize t h e N the  0p  T a b l e s 2.3a and b  recommendations f o r c r o p s i n West Germany and  Netherlands. In  Belgium  t h e N , u method i s used,  but t h e N «  P  value i s  27  Table 2.3a  Essential data of Nmin method for crops grown i n deep s o i l s . (Adapted from Wehrmann and Scharpf 1982)  S o i l analysis Time Crop plants  Soil depth cm  Total N supply ( s o i l N + N applic.) including top dressing  Winter Wheat Winter Barley Winter Rye Oats  Feb/Mar  90  140  seed-time  90  100  Sugar Beet Potatoes  Mar or May May/June  90  220  60  300  Cabbage Cauliflower Spinach Peas Beans  Plant-time  Table 2.3b  n n  n  Seed-time n n  90  200  90  160  Notes  * Without  90  350  90  250**  60  250*  30 60  **  80  1 0 0 kg ha"' must be i n top 0 - 3 0 cm  140**  Rapid N test before the usual date of top dressing for Winter Wheat.  Test value at booting stage or ear emergence resp.  0  - 1  1  -  2  2 -  3  N-application at booting stage (kg ha"' )  50 -  40  40 -  20  20 -  0  N-application at ear emergence (kg ha"' )  90 -  60  60 -  30  30 -  0  r e f i n e d by m o d i f i c a t i o n s f o r s o i l humus content, NH*-N, N content of p r e v i o u s crop and o r g a n i c manure.  Boon (1985) showed  recommendations i n c o r p o r a t i n g these m o d i f i c a t i o n s t o be s i g n i f i c a n t l y improved over the simple N, „  method.  t  In  the Netherlands,  i n areas where s o i l s c o u l d not  analyzed f o r N i n s p r i n g , a g e n e r a l g u i d e l i n e was recommendation was  based  be  given.  This  on 45 f i e l d s with a range of preceding  crops sampled s e v e r a l times d u r i n g winter.  Values were compared  with p r e v i o u s y e a r s ' f i g u r e s ,  and recommendations made f o r each  p r e c e d i n g crop t a k i n g account  of the d e v i a t i o n from  fertilizer  N needed i n p r e v i o u s years.  c o n f i d e n c e i n s o i l sampling  The high i n t e r e s t  i n the Netherlands causes  samples t o be taken each year  It i s u n l i k e l y that there w i l l  for  and  10,000  (Cooke 1980).  SOIL SAMPLING METHODS PROPOSED IN EASTERN  i n f o r m a t i o n i n the LFV  the  USA  ever be s u f f i c i e n t r e s e a r c h  t o develop such p r e c i s e recommendations  a s p e c i f i c crop as those used i n Benelux and West Germany,  however the g e n e r a l p r i n c i p l e s and some of the r e s e a r c h performed  i n Western Europe c o u l d be a p p l i c a b l e t o LFV  conditions.  An approach,  one being proposed  p o s s i b l y more s u i t a b l e t o the LFV,  i n some of the E a s t e r n S t a t e s of the  T h i s r e g i o n , i n a s i m i l a r f a s h i o n t o the LFV, thought  t o be u n s u i t a b l e f o r s o i l sampling  winter r a i n f a l l . the importance fertilizer  However, i n 1982  is  USA.  was p r e v i o u s l y  due t o the heavy  M e i s i n g e r e t a l . demonstrated  of a c c o u n t i n g f o r s p r i n g s o i l N when making  recommendations i n Maryland.  Likewise, Fox  and  29 Piekelek  (1983) i n Pennsylvania,  Vermont, and Ruby and G r i f f i n  Magdoff et a l . (1984) i n  (1985) i n C o n n e t i c u t have a l l  r e p o r t e d the v a l i d i t y of a s p r i n g s o i l t e s t f o r N on humid region  soils.  The recommendation system now i n s t e a d of being based fertilizer  levels,  being proposed  i n Eastern  USA,  on f i e l d t r i a l s with a range of a p p l i e d  i s based  on t r i a l s which i n v o l v e d p a i r e d  comparisons between p l o t s with no a p p l i e d f e r t i l i z e r N (apart from s t a r t e r ) and those with j u s t one r a t e of a p p l i e d N (Dahnke et a l . 1977;  Fox  and P i e k e l e k 1983;  u s i n g the Cate-Nelson 1971; Yield'  Magdoff et a l . 1984).  S t a t i s t i c a l Procedure  Nelson and Anderson 1977)  (Cate and  a p p l i e d t o a graph  By  Nelson  of ' R e l a t i v e  ( i e . y i e l d of c o n t r o l p l o t / y i e l d of f e r t i l i z e d p l o t )  versus s o i l NQ -N, the t r i a l s i t e s c o u l d be s p l i t 3  into  two  c a t e g o r i e s ; a ) ' P r o b a b l e Response t o F e r t i l i z e r ' and b ) ' U n l i k e l y Response t o F e r t i l i z e r ' depending on the l e v e l of s o i l N0 -N 3  found i n s p r i n g i n the 0-30cm depth. s e p a r a t e s two  The Cate-Nelson  p o p u l a t i o n s by means of a ' C r i t i c a l L e v e l ' .  C r i t i c a l L e v e l i s found by d i v i d i n g a Y-X quadrants, quadrants  procedure  maximising  The  scattergram i n t o f o u r  the number of p o i n t s i n the  positive  while m i n i m i z i n g them i n the n e g a t i v e quadrants.  When  t h i s i s done, the p o i n t a t which the v e r t i c a l a x i s of the quadrant  c u t s the y - a x i s of the s c a t t e r g r a m i s the  C r i t i c a l Level.  F e r t i l i z e r recommendations were made on  the  b a s i s of a l i n e a r - l i n e a r model with the i n t e r s e c t i o n of the l i n e s c o r r e s p o n d i n g t o the C r i t i c a l L e v e l . recommendations proved  Although  the  i m p r e c i s e where s i t e s had a low  two  30 p r o b a b i l i t y o f response,  they were g r e a t l y improved  p r e v i o u s recommendations which an e f f o r t t o improve  of  d i d not i n c l u d e a s o i l  the p r e c i s i o n o f the system,  'Unresponsive' s i t e s ,  test.  especially  In on  Magdoff e t a l . (1983) i n v e s t i g a t e d the use  a N a v a i l a b i l i t y t e s t based on NH*-N r e l e a s e d by  i n comparison  over  autoclaving  t o the simple m i n e r a l N e x t r a c t e d with 2M KCl.  T h e i r r e s u l t s showed t h a t although a u t o c l a v i n g p r o v i d e d a reasonable basis f o r estimating s o i l was  N availability,  the method  time consuming and needed g r e a t c a r e t o assure r e p r o d u c i b l e  results. The system  ' P r o b a b l e / P o s s i b l e Response' method o f recommendation i s not as p r e c i s e as the 'N. ' l n  system but i s more  adaptable t o a v a r i e t y o f crops and c o u l d p o s s i b l y be for  the LFV u s i n g l o c a l and f o r e i g n r e s e a r c h r e s u l t s .  g e n e r a l , reviews of s o i l systems  based on s o i l  uniform s o i l  sampling systems  In  suggest t h a t a d v i s o r y  a n a l y s i s a r e most e f f e c t i v e i n areas with  and a wide range i n m i n e r a l s o i l  c o n d i t i o n s do not p r e v a i l , to  developed  N; when such  'N Index' or 'Budget' systems  appear  be more r e l i a b l e .  2.2.3  SOIL NITROGEN INDEX SYSTEMS ' S o i l N Index Systems' r e f e r i n t h i s review t o p r e d i c t i v e  methods which do not i n v o l v e s o i l sampling.  In the U.K.  and some  s t a t e s o f the U.S.A. c o n s i s t e n t c o r r e l a t i o n s between N0 -N i n the 3  s o i l and crop response have e i t h e r not been found or not yet been i n v e s t i g a t e d .  In these areas N recommendations are  g e n e r a l l y made on the b a s i s o f crop t r i a l s ,  they c o n s i s t o f  31 i n d i c e s which are e s t i m a t e s o f the o t h e r than f e r t i l i z e r .  N a v a i l a b l e from sources  In the U.K.,  the  i n a b i l i t y to  c o r r e l a t i o n s s i m i l a r t o those found i n Benelux and i s suggested by Needham (1984) to be due s o i l conditions, LFV,  with r e s p e c t  r o o t i n g depths and to climate,  Europe than the U.K., higher.  t o the more v a r i a b l e  growing season c l i m a t e .  i s more comparable t o  The  continental  although winter r a i n f a l l i n the LFV  the  is  l a c k o f experimental data i n the  would p o s s i b l y make the r e g i o n U.K.  West Germany,  However, the wide range of s o i l types, the v a r i e t y  c r o p p i n g systems and  the  find  LFV,  more amenable t o methods used i n  than those used on the European  Table 2.2  of  continent.  (Sec.2.2.2) summarizes N recommendation methods  used i n s t a t e s a c r o s s the U.S.A., v i r t u a l l y a l l the f a c t o r s used for  d e r i v i n g N i n d i c e s are shown i n t h i s t a b l e .  f a c t o r s are s o i l p r o p e r t i e s  or p r o d u c t i v i t y ,  p r e v i o u s c r o p p i n g to legumes.  The  The  most common  manure use  and  relative contributions  of  each o f these f a c t o r s v a r i e s from s t a t e to s t a t e a c c o r d i n g research  c a r r i e d out  i n the r e g i o n .  average N c r e d i t s f o r manure and  Table 2.2  to  a l s o shows the  legumes i n v a r i o u s  regions i n  the U.S.A.. N i n d i c e s sometimes take o r g a n i c matter i n t o  consideration  although t h e r e i s c o n f l i c t i n g evidence as t o whether t h i s  factor  i s d i r e c t l y r e l a t e d t o a v a i l a b l e N.  Some r e s e a r c h e r s (Needham  1984,  suggest t h a t t h e r e i s only  Greenwood 1982,  Stanford  a r e l a t i o n s h i p when the r e g i o n o r g a n i c matter l e v e l s eg. generally  1982)  o f study c o n t a i n s a wide range of  0-15%.  a t t r i b u t e d to v a r y i n g  The  l a c k of r e l a t i o n s h i p i s  mineralization  r a t e s due  mainly  32 to  the growing season c l i m a t e , and the C/N  matter which i s i n p a r t due  r a t i o of the o r g a n i c  t o p r e v i o u s cropping.  C a r t e r et  a l . (1975) d i d show t h a t the amount of N s u p p l i e d from m i n e r a l i z a b l e sources i n a f i e l d c o n t i n u o u s l y p l a n t e d t o crop, c o u l d be expected next.  They suggested  t o remain constant from one year to the  t h a t once the m i n e r a l i z a t i o n c a p a c i t y of  the s o i l had been determined every few  one  the t e s t need only be  years u n l e s s unusual  fertilizer  repeated  p r a c t i c e s had been  applied. Needham (19S4) concluded  t h a t i n the U.K.,  the only f a c t o r s  which c o n s i s t e n t l y i n f l u e n c e d the crop requirement were s o i l type and p r e v i o u s cropping. the  From these two  ' S o i l N Index' (MAFF 1985-86) has been developed  simple but reasonably fertilizer depth,  split  applications.  the t e x t u r e - d e p t h r e l a t i o n s h i p being important  i n the  The p r e v i o u s c r o p p i n g regimes are  i n t o t h r e e l e v e l s a s s i g n e d the i n d i c e s 0, 1 or 2, based on  applied.  and the  fertilizer  F i e l d s i n Index 0 have low N r e s e r v e s and more N  fertilizer  i s needed compared t o f i e l d s i n Index 1.  s o i l s have the h i g h e s t s o i l N r e s e r v e s .  permanent pasture, considered.  h i s t o r i e s l o n g e r than one year  T a b l e 2.4  Index 2  U s u a l l y only the  crop grown i s used, but a f t e r l u c e r n e ( a l f a l f a ) ,  - 1  to g i v e a  S o i l type i s based on t e x t u r e and  the amount o f crop r e s i d u e s remaining  ha  factors  r e l i a b l e recommendation system f o r N  r e t e n t i o n of r e s i d u a l N.  U.K..  f o r added N  long l e y s ,  shows the N Index system used i n the - 1  - 1  and  are  Recommended v a l u e s f o r s i l a g e corn are 60 kg h a , and 40kg ha  last  f o r i n d i c e s 0,  1 and 2 r e s p e c t i v e l y .  40 kg  Table 2.4  Nitrogen Index - based on l a s t crop grown (MAFF F e r t i l i s e r recommendations 1985-86)  Nitrogen Index 0  Nitrogen Index 1  Nitrogen Index 2  Cereals  Beans  Forage crops removed  Forage crops grazed  Any crop i n f i e l d receiving large frequent dressings of  Leys (1-2 year) cut  Leys (1-2 year) grazed, high N(b)  farmyard manure or s l u r r y  Leys (1-2 year) grazed, low N(a)  Long l e y s , low N(a)  Long l e y s , high N(b)  Maize  Oilseed rape  Lucerne  Permanent pasture poor q u a l i t y , matted  Peas  Permanent pasture average  Sugar beet, tops removed  Sugar beet, tops ploughed i n  Permanent pasture high N(b)  Vegetables receiving l e s s than 200 kg ha" N 1  Vegetables receiving more than 200 kg ha"' N  (a) Low N - l e s s than 250 kg h a N per year and low clover content (b) High N - more than 250 kg ha"' N per year o r high clover content -1  34 Adjustments are o n l y made f o r manure i f g r e a t e r than 50 m* of  cow  ha"  1  s l u r r y i s a p p l i e d s h o r t l y b e f o r e sowing; i f t h i s i s the  case no a d d i t i o n a l N i s recommended,  (MAFF  1985-86).  Host o f the s t a t e s i n the U. S. A. which use N i n d i c e s use some form o f 'Balance Sheet' o r 'Budget System'  (Hauck,  used i n France (Remy and Viaux 1982), S w i t z e r l a n d Vez 1981)  and Sweden (Nommik 1979).  r e f i n e m e n t s o f the N Index System  1984)  as  (Neyroud et  These can be c o n s i d e r e d as  i n that y i e l d potential i s  taken i n t o account, and u s u a l l y o t h e r f a c t o r s as w e l l as s o i l t e x t u r e and p r e v i o u s c r o p p i n g are c o n s i d e r e d . Balance Sheet method  E s s e n t i a l l y the  i n v o l v e s c a l c u l a t i n g the d e s i r e d y i e l d  and  a s s o c i a t e d N requirement and s u b t r a c t i n g from t h i s a l l the estimated N i n p u t s . S.  B e r t r a n d (1984, p e r s o n a l communication  Loewen, Coast A g r i F e r t i l i z e r s ,  A b b o t s f o r d B.C.)  suggested  an N balance method f o r crop N requirements i n the LFV, f u r t h e r r e s e a r c h i s necessary t o r e f i n e t h i s .  with  however  A number o f the  areas u s i n g a Balance Sheet method a l s o i n c l u d e e i t h e r a f a l l or s p r i n g s o i l sample f o r N, perhaps producing the most comprehensive o f a l l N f e r t i l i z e r  2.2.4  recommendation  systems.  COMPUTER MODELLING  Computer m o d e l l i n g f o r use i n N f e r t i l i z e r  p r e d i c t i o n s i s an  approach being i n v e s t i g a t e d i n a number o f l o c a t i o n s i n Western Europe.  Most o f the models have been designed t o s i m u l a t e the  amount of m i n e r a l N i n the s o i l p r o f i l e i n s p r i n g Neeteson 1984).  ( W i l l i g e n and  These models have e v o l v e d because o f the  l o g i s t i c a l problems c o n c e r n i n g c o l l e c t i n g and a n a l y z i n g  soil  35 samples from many s i t e s In the s p r i n g and making recommendations i n good time f o r f e r t i l i z e r s p e c i f i c a l l y i n the U.K.  application.  Other  models,  (Greenwood et a l . 1984,  George  1982)  have been designed t o s i m u l a t e crop response t o N f e r t i l i z e r i n order t o i d e n t i f y why  t h e r e i s o f t e n l i t t l e c o r r e l a t i o n between  the c r o p ' s N f e r t i l i z e r In  1983  requirement  and N a v a i l a b i l i t y  a workshop i n the Netherlands  brought  together  r e s e a r c h e r s i n Western Europe t h a t were d e s i g n i n g and N c y c l e s i m u l a t i o n models,  indices.  developing  ( W i l l i g e n and Neeteson 1984).  At the  workshop, the p a r t i c i p a n t s were asked t o run t h e i r models with a data s e t of e x p e r i m e n t a l r e s u l t s c o l l e c t e d between November and June 1978, the  from a N f i e l d experiment  1977  i n the c e n t r a l p a r t of  Netherlands. Table 2.5  summarizes the s i x d i f f e r e n t models and  the  processes each of them c o n s i d e r . A l l the models c a l c u l a t e m i n e r a l i z a t i o n as a f u n c t i o n of environmental c o n d i t i o n s (temperature  and/or water content) and aim t o p r e d i c t  m i n e r a l N i n the p r o f i l e over w i n t e r and s p r i n g .  soil  They a l l d e a l  with the f a t e of N i n the unsaturated zone of the s o i l  profile.  T r a n s p o r t of water and s o l u t e s i s taken t o be e s s e n t i a l l y i n the vertical direction. into layers, throughout,  In a l l models the s o i l p r o f i l e i s d i v i d e d  i n which each l a y e r i s c o n s i d e r e d t o be i . e . w i t h i n a l a y e r no g r a d i e n t s w i l l  uniform  develop.  F i g u r e 2. shows the measured and s i m u l a t e d course of N0 -N 3  i n the a r a b l e l a y e r , and proposed one  i n the upper 60cm, from the model  by A d d i s c o t t ( W i l l i g e n and Neeteson 1984).  of the most a c c u r a t e models.  In g e n e r a l , the  This  was  relatively  Table 2.5  Summary o f processes considered i n the 6 models presented a t the N cycle simulation model workshop - Netherlands 1983. (Adapted from W i l l i g e n and Neeteson 1984)  Model Process  I  II  1. Mineralization/immobilization  +  +  2. Growth and decay o f biomass 3. N i t r i f i c a t i o n 4. D e n i t r i f i c a t i o n  +  _  5. Flux of water 6. Leaching o f n i t r a t e  + +  7. Adsorption o f ammonium  +  VI  V  VI  +  +  + +  +  -  -  + +  + +  + +  -! +  + +  -  -  -  -  -  -  III  _  (+ = process considered; - = process ignored o r input required) ! For d e n i t r i f i c a t i o n a separate model has been developed. 1! In a newer version d e n i t r i f i c a t i o n i s also considered. Model  Institute  Reference  I II  Rothamsted Experimental Station Nat. Veg. Research Station Wellesbourne, UK University o f Leuven, Belgium University o f Hanover ITAL Wageningen, Netherlands Institute f o r Soil F e r t i l i t y  Addiscott (1977,1982) Burns (1974,1975,1976)  III IV V VI  Haren, Netherlands  Seligman and Van Keulen (1981) Richter e t a l . (1978,1980) Van Veen and F r i s s e l (1981) Zandt and De Willigen (1981)  -  Soil mineral N 120r (kg ha") measured simulated  Model I 0-30cm A A A  0-60cm • • o  80 o  40 A  A A  A > A A A ^ -A-A-A'  ~ "\TA" A  0  80  I  160  240  days  F i g u r e 2. Measured and simulated  course o f n i t r a t e -  n i t r o g e n i n t h e a r a b l e l a y e r and i n t h e upper 60cm. ( W i l l i g e n and Neeteson 1984)  38 simple  models I , I I , I V and  models I I I and  V.  The  VI were more a c c u r a t e  mean computed by each of these f o u r  models d i f f e r e d by l e s s than 10 kg h a experimental  mean.  than the complex  - 1  o f N from  the  Host of the problems found i n modelling  N c y c l e appeared t o be caused by the m i c r o b i o l o g i c a l The  d i s c r e p a n c i e s between p r e d i c t e d and  were due  to overestimation  the  processes.  measured N0 -N  contents  a  of N m i n e r a l i z a t i o n .  Greenwood et a l . (1984) r e i t e r a t e d the p o i n t t h a t s i m u l a t i o n models tended t o be more accurate.  simpler  T h e i r model f o r  i n t e r p r e t i n g N - f e r t i l i z e r t r i a l s r e q u i r e d o n l y f o u r out of a p o s s i b l e 60 i n p u t c o e f f i c i e n t s , yield,  these were; p o t e n t i a l maximum  the m i n e r a l i z a t i o n r a t e , the d i s t r i b u t i o n of  down the s o i l p r o f i l e ,  and  the s t a r t of modelling.  inorganic-N  the weight of dry p l a n t m a t e r i a l at  The  researchers  a l s o admitted however,  t h a t t h i s s i m p l i f i c a t i o n l i m i t e d the range of c o n d i t i o n s where the model c o u l d be a p p l i e d . expected t o apply  For i n s t a n c e ,  i t c o u l d not  without f u r t h e r amendment where t h e r e  s i g n i f i c a n t s p r i n g l e a c h i n g or d e n i t r i f i c a t i o n , monthly incoming r a d i a t i o n v a r i e d c o n s i d e r a b l y growing p e r i o d . t h e i r model has  Nevertheless,  of f e r t i l i z e r The  t o need and  or where the during  the  i n adjusting N  that  fertilizer  thereby improving the  efficiency  use.  usefulness  of computer modelling  s o i l n i t r a t e i s probably t o the high winter l e a c h i n g and  was  Greenwood et a l . (1984) f e l t  p o t e n t i a l f o r use  p r a c t i c e according  be  for predicting spring  of l i t t l e value i n the LFV,  r a i n f a l l and  denitrification.  t h i s i s due  consequent p o t e n t i a l f o r s p r i n g However, a computer model may  be  of c o n s i d e r a b l e value i n combining i n f o r m a t i o n from worldwide l i t e r a t u r e and l o c a l r e s e a r c h ,  t o develop some form o f Balance  Sheet system f o r N recommendations i n the V a l l e y .  The Manure  Management Model p r e v i o u s l y mentioned ( S e c t i o n 2.1.3, B u l l e y and Cappelaere 1978), a l r e a d y encompasses a n i t r o g e n behaviour s e c t i o n w i t h i n which t h e r e are programmes s i m u l a t i n g growth f o r corn and grass.  The model enables  Management G u i d e l i n e s  the farmer t o use the Manure  (Bertrand and B u l l e y 1985) t o p r e d i c t how  much manure i s r e q u i r e d from a s p e c i f i c i n order t o supply  livestock/manure  adequate N t o a f o r a g e crop which has one o f  three p o t e n t i a l y i e l d s .  A simple  conversion  procedure i s shown  to adapt the g u i d e l i n e s t o crops other than f o r a g e s . foundation  i n computer modelling  g r e a t value f o r improving besides  system  This  o f N i n the LFV c o u l d be o f  recommendations f o r other N sources,  manure.  2.3 APPROACH USED IN THIS STUDY  In view o f the c u r r e n t p r a c t i c e s f o r N recommendations i n humid r e g i o n s and the a s s o c i a t e d l i t e r a t u r e t h e approach taken i n t h i s study s o i l test fertilizer corn  was t o i n v e s t i g a t e the a p p l i c a b i l i t y o f a s p r i n g  and/or a s o i l N Index System f o r improving recommendations i n the LFV.  (Zea Mays saccharata)  N  The approach used sweet  as t h e t r i a l crop.  Corn was chosen  because i t i s a common and h i g h l y v a l u a b l e crop i n the r e g i o n o f study, and  and a crop which i s g e n e r a l l y r e s p o n s i v e  r e l a t i v e l y simple  t o use f o r f i e l d  trials,  to N f e r t i l i z e r re. uniformity.  harvesting etc..  F u r t h e r r e s e a r c h would be r e q u i r e d t o apply  the r e s u l t s o f t h e p r o j e c t t o o t h e r crops i n t h e r e g i o n . With r e s p e c t t o a s p r i n g s o i l t e s t the p r o j e c t aimed t o answer t h e f o l l o w i n g q u e s t i o n s : a) Are s o i l  N0 -N o r NH*-N o r both, 3  with crop response  sufficiently  t o make a s o i l t e s t  b) I f a s o i l t e s t can be used,  correlated  worthwhile?  t o what depth and on what  date i s i t necessary t o sample? The q u e s t i o n s addressed  r e g a r d i n g t h e N Index System were:  a) Can t h e N s u p p l i e d by t h e s o i l be i n d i r e c t l y estimated by s o i l c h a r a c t e r i s t i c s such as o r g a n i c matter, cropping, s o i l  previous  texture?  b) Which f a c t o r s have t h e g r e a t e s t i n f l u e n c e on corn uptake of One  s o i l and f e r t i l i z e r N?  f u r t h e r q u e s t i o n posed i n t h e study was; Once a  recommendation has been made, does t h e method o f f e r t i l i z e r application,  i e . broadcast p r e p l a n t , o r s i d e d r e s s e d when t h e  crop i s about 30 cm t a l l , crop use o f f e r t i l i z e r In  make a s i g n i f i c a n t d i f f e r e n c e t o the  N?  order t o answer t h e q u e s t i o n s above, t h e p r o j e c t was  composed o f two i n t e r c o n n e c t e d s t u d i e s which were s e t up as follows: 1) The e s t a b l i s h m e n t o f a ' R e p l i c a t e d F e r t i l i z e r Trial' to  Response  which aimed t o : (a) Monitor s o i l NO,-N and NH«-N  a depth o f 80cm a t i n t e r v a l s o f 0-20cm, 20-50cm and  50-80cm. (b) I n v e s t i g a t e y i e l d response  and N uptake  e f f i c i e n c y at four d i f f e r e n t rates of sidedress applied  41 urea,  (c) Compare the e f f e c t i v e n e s s of s i d e d r e s s and  p r e p l a n t a p p l i e d urea. 2) A 'Multifarm Survey'  of s i d e d r e s s e d versus c o n t r o l  plots  at 28 l o c a t i o n s i n the Ladner area over a 2 year p e r i o d . T h i s aimed t o e s t a b l i s h the range of N s u p p l y i n g c a p a c i t i e s of some LFV s o i l s and r e l a t e these t o other s o i l p r o p e r t i e s and crop h i s t o r y .  3.  was  METHODS  The study, which covered two f i e l d seasons,  1984 and 1985,  l o c a t e d on Westham I s l a n d and i n t h e Ladner  area a t t h e  mouth o f t h e F r a s e r R i v e r , 35 km south o f Vancouver, Columbia silt  (Fig.3.).  British  The s o i l s i n t h i s area a r e mostly  gleysols,  loams t o s i l t y c l a y loams with o r g a n i c matter i n t h e plough  l a y e r v a r y i n g from 2. 0 t o 9. 5'/.. The r e g i o n vas chosen  f o r the  study because o f i t s p r o x i m i t y t o Vancouver and because farmers w i l l i n g t o cooperate i n t h e study were known i n t h e d i s t r i c t . The area produces  high v a l u e v e g e t a b l e crops i n need o f improved  N f e r t i l i z e r recommendations.  Sweet corn, t h e crop chosen f o r  the study, i s grown i n t h e r e g i o n mainly f o r canning and freezing. Table 1. (Sec.1.1) showed t h e monthly p r e c i p i t a t i o n and temperature  summaries f o r Vancouver I n t e r n a t i o n a l  approximately  10 km from t h e study s i t e s .  Airport,  Summer r a i n f a l l i n  both 1984 and 1985 was w e l l below t h e 30 year average. r a i n f a l l measurements over t h e growing  Daily  season a r e recorded i n  Appendix 1.  3.1  PROJECT DESIGN  The p r o j e c t c o n s i s t e d o f f o u r i n t e r r e l a t e d  parts:  1) S o i l N m o n i t o r i n g d u r i n g s p r i n g . 2) A ' R e p l i c a t e d F e r t i l i z e r Response T r i a l ' with f o u r r a t e s of a p p l i e d urea.  MULTIFARM  TRIAL: PLOT  F i g u r e 3. M u l t i f a r m t r i a l  LOCATIONS  plot locations , Delta  M u n i c i p a l i t y , B r i t i s h Columbia.  3) A comparison of 'Preplant versus S i d e d r e s s ' a p p l i e d urea fertilizer. 4) A 'Multifarm Survey' of s i d e d r e s s e d control  3.2  versus  plots.  FIELD METHODS  3.2.1  NITROGEN MONITORING STUDY. FERTILIZER RESPONSE TRIAL  AND  PREPLANT VERSUS SIDEDRESS UREA STUDY These s t u d i e s were conducted i n c o o p e r a t i o n with Mr.Hugh Reynolds, at Reynelda Farms, Westham I s l a n d , B.C.. used i n both  1984  grow sweet corn, S i t e A was  ( S i t e A) and variety  1985  to  fields  ( S i t e B) were c o n t r a c t e d to  ' J u b i l e e ' , f o r Royal C i t y Foods L t d . .  s i t u a t e d on medium t o moderately f i n e t e x t u r e d  d e l t a i c d e p o s i t s of the Crescent 1983  The  series,  i t had been i n peas i n  f o l l o w e d by a cover crop of s p r i n g b a r l e y .  the peas were potatoes  i n 1982  The  and corn i n 1981.  crops  prior  S i t e B had  been i n s t r a w b e r r i e s f o r f i v e years p r i o r t o the experiment, i t was  s i t u a t e d adjacent t o S i t e A, separated  and was  a l s o of the Crescent s e r i e s .  somewhat i n s o i l c h a r a c t e r i s t i c s . texture,  The two  relatively  low pH range, between 4 and  differed  Both s i t e s had  soil 3.8%, a  5, and S i t e B c o n t a i n e d  S0 -S, Fe and 4  ditch  (2.4% compared t o  a h i g h e r bulk d e n s i t y .  n o t a b l y h i g h e r q u a n t i t i e s of Na,  sites  S i t e A had a c o a r s e r  a lower o r g a n i c matter content  0-20cm depth) and  by a drainage  B plus a  s u b s t a n t i a l l y g r e a t e r e l e c t r i c a l c o n d u c t i v i t y (Appendix 2).  PLOT LAYOUT The experimental d e s i g n f o r both s i t e s was a complete  randomized  b l o c k d e s i g n with s i x treatments and f i v e  Four o f t h e s i x treatments belonged  replicates.  t o the ' F e r t i l i z e r Response  T r i a l ' and c o n s i s t e d o f f o u r r a t e s o f urea, 0,50,100 and 200 kg ha"  1  o f N a p p l i e d t o 4m x 6m p l o t s .  The two remaining  c o n t a i n e d the 'Preplant versus S i d e d r e s s ' urea t r i a l , c o n s i s t e d o f 100 kg ha~ kg ha~  1  1  o f N as urea a p p l i e d p r e p l a n t , and 100  (Appendix 3 ) .  1985 a second f i e l d t r i a l  ( S i t e C) was conducted  s i m i l a r manner t o those a t Reynelda in  which  o f urea N a p p l i e d a t s i d e d r e s s time, when the corn was  approximately 30cm t a l l In  treatment:  Farms. The t r i a l was s e t up  c o o p e r a t i o n with Mr. John Malenstyn  s i t u a t e d on the mainland  of Jowkema Farms and was  7km E a s t o f Westham I s l a n d .  on S i t e C was o f the Westham s e r i e s , p r e v i o u s year and was chosen  in a  The s o i l  i t had been i n corn the  f o r i n v e s t i g a t i o n because i t  c o n t a i n e d l e s s N0 -N than S i t e B a t s i d e d r e s s time. 3  The p l o t  l a y o u t was i d e n t i c a l t o t h a t used on S i t e s A and B with the omission o f the P r e p l a n t versus S i d e d r e s s Urea T r i a l ie. at  t h e r e were four, not s i x treatments, 0,50,100 and 200 kg ha"  1  treatments,  replicated five  times  urea N.  METHODS OF FERTILIZATION The urea a p p l i e d at p r e p l a n t was broadcast by hand on 29 May in  1984 and on 8 May i n 1985.  The s i d e d r e s s e d urea was a p p l i e d  each year on a date when the corn was approximately 30cm t a l l , (13 J u l y 1984, 20 June 1985).  A push-plough  was used t o make a  46 5-10cm deep furrow s i d e o f t h e row.  15cm away from t h e corn along the r i g h t - h a n d The f e r t i l i z e r  was p l a c e d i n t o t h i s furrow and  then covered with s o i l u s i n g a rake. s i d e d r e s s urea, 47 kg ha"  1  In a d d i t i o n t o t h e  o f N was d r i l l e d  below and t o t h e s i d e o f the seed.  as a s t a r t e r , 5cm  The seed was custom p l a n t e d  by a s i n g l e c o n t r a c t o r (Mr. John Malenstyn) u s i n g a row width o f 1.0 m.  SOIL MEASUREMENTS A l l 30 p l o t s were s o i l sampled b e f o r e p l a n t i n g , 1984, 1 May 1985), a t s i d e d r e s s time, 1985) and again a t h a r v e s t ten  (18 Sept  (29 May  (13 J u l y 1984, 20 June  1984, 25 August 1985).  The  p l o t s comprising the P r e p l a n t versus S i d e d r e s s t r i a l were  sampled f o r t n i g h t l y ,  from 25 A p r i l t o 4 J u l y 1984, and 8 May t o  16 J u l y 1985 f o r t h e S o i l N M o n i t o r i n g Study. c o n s i s t e d o f t e n composited  soil  A sample  c o r e s from each p l o t ,  were taken with an o a k f i e l d sampling  these  probe from between the corn  rows a t depths o f 0-20, 20-50 and 50-80cm.  The samples were  t r a n s p o r t e d i n c o o l e r s t o t h e l a b o r a t o r y , where they were s t o r e d at  2°C u n t i l e x t r a c t i o n , Six  which was w i t h i n 24 h o f sampling.  bulk d e n s i t y c o r e s (volume = 510.5cm ) were taken a t a 3  depth o f 10cm on every sampling  date.  Two cores were taken a t  depths o f both 35cm and 65cm from a p i t dug on t h e f i r s t sampling  date i n each  S o i l temperatures  soil  season. were recorded throughout  e x p e r i m e n t a l p e r i o d with thermocouple probes 10cm, 35cm and 65cm. These probes  t h e 1984  at three  depths;  were a t t a c h e d t o a r e c o r d e r  47 which m a l f u n c t i o n e d i n 1985, for  1985  are temperatures  thus the s o i l temperature  data used  r e c o r d e d at a depth of 10cm  on a  d r a i n e d p l o t at the Boundary Bay drainage experiment,  10.5  E a s t of the t r i a l s i t e .  The temperatures  f o r each sampling  were c a l c u l a t e d as a mean of the d a i l y temperatures fortnightly soil  sampling  intervals.  and h a r v e s t i n g , were performed  farmer-hired  date  over the  A l l management p r a c t i c e s on the e x p e r i m e n t a l p l o t s , fertilizing  km  except  by the farmer or a  contractor.  CROP HARVEST Harvest of the e x p e r i m e n t a l p l o t s was machete.  done by hand, u s i n g a  H a r v e s t i n g c o n s i s t e d of c u t t i n g two,  2m rows of corn  i n each p l o t ; from these, numbers of cobs, s t a l k s , were t a l l i e d ,  and  tillers  and s t a l k and cob f r e s h weights were obtained.  F o l l o w i n g weighing,  f i v e s t a l k s and f i v e cobs were randomly  s e l e c t e d from each p l o t f o r moisture and t o t a l N d e t e r m i n a t i o n s f o l l o w i n g oven d r y i n g at S5°C. About one month b e f o r e harvest, farmers  'Top' t h e i r sweet  corn t o prevent p l a n t s t a n g l i n g and slowing h a r v e s t o p e r a t i o n s . 'Topping',  f o r the farmer,  p l a n t by machine.  i n v o l v e s c u t t i n g the top 50 cm of the  In o r d e r t o a v o i d l o s i n g the tops of the  experimental plants,  t o p p i n g was  performed  u s i n g r o s e c u t t e r s b e f o r e the f i e l d  was  on each s i t e by hand  m e c h a n i c a l l y topped.  The tops were gathered, d r i e d and weighed, and a subsample l a t e r added t o the s t a l k subsample c o l l e c t e d at harvest.  was  3.2.2  MULTIFARM SURVEY OF SOIL NITROGEN SUPPLYING  ABILITY  T h i s study was c a r r i e d out i n c l o s e c o o p e r a t i o n with Mr. I r v i n e S c h i n k e l , Royal C i t y Foods L t d . on 28 s i t e s  <17 i n 1984,  11 i n 1985)  on farms c o n t r a c t e d t o grow sweet corn f o r  processing.  At each s i t e two treatments were a p p l i e d :  <1) A four-row wide ' c o n t r o l ' s t r i p o f corn r e c e i v i n g the 47 kg h a  - 1  only  o f s t a r t e r N.  (2) A p a i r e d comparison s t r i p , s t a r t e r N, 135 kg h a  - 1  r e c e i v i n g i n a d d i t i o n t o the  of urea-N when the corn was 30cm  tall. 20m  from the headlands w i t h i n each treatment s t r i p ,  p l o t was s o i l sampled  a 6x4m  at s i d e d r e s s time and again at harvest.  The s o i l sampling and h a r v e s t i n g methods were the same as those d e s c r i b e d f o r the F e r t i l i z e r Response  Trial  (Sec.3.2.1). In  c o n t r a s t t o the R e p l i c a t e d F e r t i l i z e r Experiment where fertilizing  was done manually u s i n g a push-plough, N  s i d e d r e s s i n g i n the M u l t i f a r m Study was c a r r i e d out on a l l p l o t by a custom o p e r a t o r .  The remainder of the f i e l d management  p r a c t i c e s except the p l o t harvest, were performed by the contracted In  growers.  o r d e r t o o b t a i n crop and s i t e h i s t o r i e s ,  questionaires  were sent t o each c o o p e r a t i n g farmer (Appendix 4).  The  f o l l o w i n g crops were found on the survey s i t e s the year p r i o r t c o r n : Peas  (10), Potatoes (7), Beans (3), S p r i n g b a r l e y (2),  Corn (2), S t r a w b e r r i e s (1), Unknown (3).  3.3  LABORATORY METHODS  S o i l moisture d e t e r m i n a t i o n s c o n s i s t e d o f d r y i n g lOg o f f i e l d - m o i s t s o i l o v e r n i g h t a t 105°C and reweighing.  The s o i l  f o r t h e bulk d e n s i t y d e t e r m i n a t i o n s was t r e a t e d i n a s i m i l a r manner. NH«-N and N0 -N were e x t r a c t e d from t h e moist s o i l 3  with 2M KCl u s i n g a 1:5 s o i l t o e x t r a c t a n t r a t i o  (20g moist  :100mL 2M KCl) and shaking f o r 1 h (Keeney 1982). settling, filter  t h e supernatant  paper,  was f i l t e r e d through  samples soil  After  Whatman #42  t h e e x t r a c t i o n s were s t o r e d a t 2°C i n 60mL b o t t l e s  c o n t a i n i n g a drop o f t o l u e n e t o i n h i b i t m i c r o b i a l growth. C o n c e n t r a t i o n s o f NH -N and N0 -N i n the f i l t e r e d e x t r a c t s were 4  determined  3  u s i n g the Autoanalyser  I I (Technicon Autoanalyser I I  Methodology 1977), as was ' T o t a l N', found i n the form o f NH*-N, a f t e r t h e p l a n t samples had been d i g e s t e d u s i n g t h e method o f Parkinson and A l l e n performed  (1975).  The t o t a l N d i g e s t i o n s were  s e p a r a t e l y on t h e d r i e d cob and s t a l k samples which  had been ground i n a Wiley m i l l t o pass a 2mm mesh s i e v e . The s o i l a n a l y s e s f o r the s i t e s i n the M u l t i f a r m T r i a l t e x t u r e . T o t a l N, Organic matter,  pH, S a l t s ,  (Soil  P, K, Mg, Ca, Na,  T o t a l c a t i o n s , Exchangeable sodium percent, SAR, SO*-S, B, Cu, Fe, Mn, and Zn) were performed  by t h e B.C. M i n i s t r y of  A g r i c u l t u r e s o i l s l a b o r a t o r y , Kelowna, u s i n g t h e i r techniques  (Appendix  5).  standard  T h i s l a b o r a t o r y a l s o analysed t h e  M u l t i f a r m T r i a l s o i l s f o r N0 -N. 3  In c o n t r a s t t o t h e technique  50 d e s c r i b e d above u s i n g  'Field-Moist' s o i l s ,  t h e 'Kelowna' method  used a i r d r i e d s o i l s which had been ground t o pass through a 2mm mesh s i e v e . Extractant  The e x t r a c t a n t used f o r N0 -N was t h e Kelowna 3  (0.25N HOAc+0.015N»F)  (van L i e r o p 1986) which was  a l s o used f o r e x t r a c t i n g many o f t h e o t h e r p l a n t n u t r i e n t s i n the s t a n d a r d a n a l y s i s .  The e x t r a c t i o n procedure i n v o l v e d  shaking a 1:10 v/v s o i l : e x t r a c t a n t s o l u t i o n a t 180 c y c l e s min"  1  f o r 5 minutes and then f i l t e r i n g through Whatman #2 f i l t e r s .  3.4  STATISTICAL ANALYSIS  1) N M o n i t o r i n g Study: Mann-Whitney U (Mann and Whitney 1947) dates.  t e s t s were used t o compare s o i l N v a l u e s on s p e c i f i c Pearson's  'r' correlation coefficients  (Hicks 1982) were  used f o r c o r r e l a t i o n s between s o i l N and temperature. 2) R e p l i c a t e d F e r t i l i z e r Response T r i a l : D i f f e r e n c e s between treatments and b l o c k s were i d e n t i f i e d with the K r u s k a l - W a l l i s One  Way A n a l y s i s o f V a r i a n c e Technique  (Kruskal and W a l l i s  1952). 3) P r e p l a n t versus S i d e d r e s s Study: Mann-Whitney U t e s t s were used t o i d e n t i f y s i g n i f i c a n t d i f f e r e n c e s between treatments. 4) M u l t i f a r m T r i a l : Pearson's r c o r r e l a t i o n  coefficients  were used f o r s c a t t e r g r a m s between s o i l parameters and corn y i e l d parameters.  Three types of r e g r e s s i o n l i n e s were f i t t e d  to these scattergrams: a) L i n e a r  (y = b  0  * b x). t  b) L o g a r i t h m i c  (y = b« • b i l o g x + b x ) . B  T h i s equation  determines whether t h e graph o f p o i n t s f l a t t e n s out as  c>  the x component  increases.  Quadratic  0  .(y = b  + bi x + b x e  8  ).  This equation  determines whether t h e shape o f the curve i s p a r a b o l i c , ie.  y values  begin t o decrease when x v a l u e s  a r e high.  Graphs o f S o i l N0 -N v e r s u s corn y i e l d parameters were a l s o 3  analyzed  using t h e Cate-Nelson procedure (Cate and Nelson 1971).  T h i s procedure i s a p p l i e d t o l o g a r i t h m i c type graphs and s p l i t s the data i n t o two p o p u l a t i o n s  using successive  tentative  ' C r i t i c a l L e v e l s ' t o a s c e r t a i n t h e p a r t i c u l a r l e v e l which maximize the o v e r a l l p r e d i c t i v e a b i l i t y o f the graph.  will  In t h i s  study, a g r a p h i c a l v e r s i o n o f the procedure was used, i t i n v o l v e d p l a c i n g over a p l o t o f t h e p o p u l a t i o n , split The  a transparency  i n t o f o u r quadrants by two l i n e s drawn a t r i g h t - a n g l e s .  method f o r f i n d i n g the C r i t i c a l L e v e l was d e s c r i b e d i n  Sec.2.2.2.. Level,  In r e a l i t y ,  there i s r a r e l y a p r e c i s e  Critical  i n s t e a d t h e v e r t i c a l l i n e c o u l d c r o s s t h e X - a x i s a t any  number o f p o i n t s w i t h i n a range which v a r i e s depending on t h e data s e t .  The data i n t h i s study was s p l i t by t h i s  graphical  method i n t o 'Responsive' and 'Unresponsive' p o p u l a t i o n s fell  i n t h e lower l e f t  which  and upper r i g h t quadrants r e s p e c t i v e l y .  4.RESULTS AND  The allowed  DISCUSSION  d e s i g n o f the p r o j e c t , with f o u r i n t e r r e l a t e d p a r t s , the r e s u l t s t o be c o n v e n i e n t l y separated  into four  sections: 1) The  Nitrogen  Monitoring  Study.  i n f o r m a t i o n on s o i l N t r a n s f o r m a t i o n s provided  T h i s s e c t i o n produced during spring,  data r e g a r d i n g optimum sampling times and  use with a s p r i n g s o i l sample should  and  depths f o r  i t be prove to  be  practical. 2) & 3) The P r e p l a n t versus  R e p l i c a t e d F e r t i l i z e r Response T r i a l s and S i d e d r e s s Urea Study.  The  r e s u l t s of  the  these  s t u d i e s showed t h e r e t o be no s i g n i f i c a n t crop response t o e i t h e r d i f f e r e n t rates of f e r t i l i z e r fertilizer negative,  application.  or t o d i f f e r e n t methods of  Such f i n d i n g s , i n s p i t e of  being  demonstrated the importance of N s u p p l i e d by the  4) The  Multifarm  Survey.  T h i s survey  i n the D e l t a r e g i o n of the LFV,  of 28 d i f f e r e n t  soil. sites  generated the g r e a t e s t amount of  i n f o r m a t i o n p a r t i c u l a r l y r e g a r d i n g the response of corn  plants  to  assess  how  soil  and  fertilizer  N fertilizer  N.  The  r e s u l t s c o u l d be used t o  recommendations i n the LFV  might be  improved.  I t must be borne i n mind t h a t the r e s u l t s here apply s p e c i f i c a l l y t o sweet corn i n the D e l t a r e g i o n of the  LFV  however they do e s t a b l i s h p r i n c i p l e s t h a t c o u l d be a p p l i e d t o other crops and  other a g r i c u l t u r a l  regions.  4. 1  NITROGEN MONITORING DURING SPRING  4.1.1  SOIL MINERAL NITROGEN. MAGNITUDE AND VARIABILITY  F i g . 4.1 shows t h e accumulated  s o i l N0 -N (kg ha" ) c o n t e n t s 1  3  measured f o r t n i g h t l y i n t h e s p r i n g a t t h e t h r e e depths; 0-20, 20-50 and 50-80cm i n both 1984 and 1985.  T a b l e s 4.1 and 4.2  emphasize t h e c o n s i d e r a b l e d i f f e r e n c e s between t h e two years i n both t h e magnitude and v a r i a b i l i t y o f N0 -N and NH*-N v a l u e s . 3  In s p i t e o f these d i f f e r e n c e s ,  a t r e n d o f N0 -N i n c r e a s i n g 3  d u r i n g s p r i n g can be seen, p a r t i c u l a r l y i n t h e 0-20cm depth. Although r e l i a b l e c o n c l u s i o n s cannot be founded on t h e b a s i s of j u s t a couple o f years r e s e a r c h , two p o i n t s can be drawn from the data.  1) That s u b s t a n t i a l q u a n t i t i e s o f m i n e r a l N a r e made  a v a i l a b l e by t h e s o i l .  2) That when sampling f o r N0 -N t h e r e 3  are l a r g e amounts o f s p a t i a l and temporal v a r i a b i l i t y . such as those i n 1985, which showed 130 kg h a  - 1  Results  i n t h e 0-80cm  p r o f i l e at s i d e d r e s s time (Table 4.1), suggest t h a t s o i l N should be taken i n t o c o n s i d e r a t i o n when f e r t i l i z e r recommendations a r e being made.  However, t h e l a r g e d i f f e r e n c e s  i n N v a l u e s , both between s i t e s and w i t h i n s i t e s ,  not o n l y  emphasise t h e importance o f s i t e sampling, but a l s o u n d e r l i n e s the d i f f i c u l t y  i n doing t h i s a c c u r a t e l y and then  interpreting  the r e s u l t s . The most obvious area o f v a r i a t i o n i s t h e d i f f e r e n c e i n N0 3  N between S i t e A and S i t e B ( F i g . 4.1).  I t i s not p o s s i b l e t o  i d e n t i f y t h e cause f o r t h i s d i f f e r e n c e because t o o many  '  f  t  APR  <  t  H  t  t  t  t  f,  »  •  T  •  ?  '  T  •  -  MAY JUN I984(SITEA) Figure  4.1  Soil  J  |  JUL  | r  f  T  1  ,  w  MAY  n i t r a t e t o a d e p t h o f 80cm d u r i n g  „  f  n  1  ,  .  n  .  |  r  r  .  JUN 1985 (SITE B)  ^  „  .  r  .  ,  .  ,  JUL  spring. ui  Table 4.1. S o i l NO -N during spring 1984 (Site A) and 1985 (Site B). a  S o i l N0,-N kg ha ' Total Date  0-20cm  CV  20-50cm CV  1984 Apr 25 May 9  50-80cm  May 23 June 7 June 20 July 4  34.4  15.4 6.3  10.0 16.5  16.0 15.2  8.5 17.6  11.8 32.4  21.1 45.1  12.9 5.5  19.7 21.9  16.2 29.7  14.2 13.5  15.5 21.5  45.5 53.4  19.6 18.9  28.9 33.0  48.8 11.2  15.5 22.6  25.2 9.3  79.8 89.9  28.0  40.3  36.0  91.8  48.2  26.8  42.1 36.4 42.8  23.0 30.0 37.4  103.4  39.1  27.3 23.5  28.1 43.1  127.2 105.3  1985  1985  May 8  14.0  33.6  May 22 June 5  19.2  17.2  28.9 42.3 40.6  30.4 21.7 13.5  48.5  19.2  38.1  31.5  7.3  42.8  22.0  31.1  July 2 J u l y 16  0-80cm  1984 2.6 11.1 11.6 18.1 35.7  June 19  CV  37.5 42.1  104.6 133.3  Planting = 29 May 1984, 8 May 1985. Sidedress = 13 J u l y 1984, 20 June 1985. Table 4.2  S o i l NH^-N during spring 1984 (Site A) and 1985 (Site B ) .  S o i l NH^-N kg ha" Date  0-20cm  CV  1984 Apr 25 May 9 May 23 June 7 June 20 July 4  July 2 J u l y 16  CV  50-80an  CV  Total 0-80cm  1984 2.3 3.5 3.9 3.6 3.4 4.2  17.4 37.1 41.0 30.1 20.6 16.7  1985 May 8 May 22 June 5 June 19  20-50cm  1  4.2 6.3 4.5 4.1 4.3 5.9  1984 43.0 46.0 17.8 29.3 18.6 16.9  2.7  18.5  9.3  27  3.9 3.2 3.4 3.2  25.6 18.8 26.5 25.0 24.1  13.7 11.6  23 20 17 12 15  5.4  11.1 10.9 15.5  1985  1985 6.7 2.6  37.3 61.5  6.3 3.9 1.8 2.9  30.2 79.5 83.3 51.7  11.5 2.8 9.9 3.3 0.5 5.6  NH^-N as % of t o t a l Mineral N  46.1 3.6 15.2 45.5 48.0 24.0  9.8 3.7 10.0 4.8 1.6 3.0  Planting = 29 May 1984, 8 May 1985. Sidedress = 13 J u l y 1984, 20 June 1985.  41.8  28.0  99.0 17.0 62.5 93.8 70.0  9.1 26.2 12.0 4.0 11.6  23 8 20 10 4 9  56 i n t e r e l a t e d f a c t o r s were i n v o l v e d .  F o r example, t h e r e were both  s i t e f a c t o r s and weather f a c t o r s ; some o f t h e s i t e  factors  being, t h e d i f f e r e n t s o i l p r o p e r t i e s . S i t e A c o n t a i n e d o r g a n i c matter,  less  more c l a y and had a lower pH than s i t e B.  Site  B had been i n s t r a w b e r r i e s f o r t h e past f i v e years, and t h e crop had been h e a v i l y t r e a t e d with a f e r t i l i z e r of  sewage sludge.  In comparison,  mix composed p a r t l y  S i t e A had been i n peas t h e  p r e v i o u s year and t h e r e f o r e t h e i n f l u e n c e o f crop and f e r t i l i z e r r e s i d u e s was minimal.  The high m i n e r a l N c o n t e n t s found i n t h e  lower depths on S i t e B (Table 4.1) may have a number o f causes, eg. ploughing i n t h e strawberry p l a n t s i n t h e f a l l , t h e fertilizer  p r c a t i c e s used on t h e s t r a w b e r r i e s , o r perhaps t h e  source and n u t r i e n t content o f t h e water beneath S i t e B was d i f f e r e n t from S i t e A. to  The high v a l u e s may a l s o have been due  t h e d i f f e r e n c e s i n t h e weather between t h e two years, s p r i n g  1984  being much c o l d e r and wetter than 1985.  f a c t o r s that a f f e c t s o i l  mineral N cannot  Thus, t h e many  be u n r a v e l l e d t o  e x p l a i n t h e d i f f e r e n t N l e v e l s between t h e two s i t e s .  Such a  complex system does however suggest t h e u s e f u l n e s s o f a m i n e r a l N s o i l sample, p a r t i c u l a r l y as c l o s e t o f e r t i l i z i n g  time as  p o s s i b l e i n order t o o v e r r i d e t h e many f a c t o r s t h a t can a f f e c t s o i l mineral N values.  4.1.2  SOIL AMMONIUM On S i t e A (1984) s o i l NH*-N v a l u e s were c o n s i s t e n t l y low  throughout In  the p r o f i l e  (9-16 kg h a " 0-80cm depth. 1  c o n t r a s t , on S i t e B (1985) NH»-N v a l u e s v a r i e d  Table  4.2).  erratically  57 from 4-28 kg h a decreased 1984  - 1  .  As a p r o p o r t i o n o f t o t a l m i n e r a l N, NH*-N  throughout  the s p r i n g , r e a c h i n g v a l u e s o f below 15% i n  and below 10% i n 1985 (Table 4.2).  T h i s decrease  probably  r e f l e c t s the i n c r e a s i n g l y f a v o u r a b l e c o n d i t i o n s f o r nitrification,  i e . warmer, d r i e r s o i l s .  The low l e v e l s o f NH*-N  i n comparison t o N0 -N imply t h a t n i t r i f i c a t i o n was keeping 3  with m i n e r a l i z a t i o n .  pace  The i n c r e a s e i n NH*-N as a p r o p o r t i o n o f  t o t a l m i n e r a l N on t h e l a s t sampling  date i n both years was  probably due t o the s t a r t o f crop uptake o f s o i l N0 -N. 3  4.1.3  SOIL NITRATE AND SOIL TEMPERATURE  S o i l N0 -N i n t h e s u r f a c e h o r i z o n showed a s t r o n g l i n e a r 3  c o r r e l a t i o n with temperature, r=0.73*»  (1985)).  (Fig.4.2, r=0.92 »» (1984),  T h i s l i n e a r c o r r e l a t i o n i s seen t o cease  b e f o r e t h e f i n a l sampling  date and, i n a s i m i l a r manner t o the  i n c r e a s e i n NH*-N as a p r o p o r t i o n o f mineral N, i s probably due t o the beginning o f d e t e c t a b l e crop uptake o f s o i l N0 -N which 3  appears 1984  t o occur about f i v e t o s i x weeks a f t e r p l a n t i n g i n both  and 1985 (Table 4.1).  4.1.4  VARIABILITY OF BULK DENSITY MEASUREMENTS S i x bulk d e n s i t y measurements were taken i n t h e 0-20cm depth  at each sampling  date o f the N monitoring study.  Table 4.3  shows t h e mean and CV v a l u e s f o r bulk d e n s i t y and s o i l N0 -N (mg 3  kg ) - 1  a t each date.  The average  CV f o r bulk d e n s i t y  measurements was s u b s t a n t i a l l y lower than f o r s o i l N0 -N (mg 3  kg ) - 1  e s p e c i a l l y i n 1985.  T h i s r e s u l t suggests t h a t t h e e r r o r  58  F i g u r e 4.2  R e l a t i o n s h i p between s o i l n i t r a t e (0-20cm) and s o i l  temperature d u r i n g  spring.  Table 4.3 Replicated F e r t i l i z e r Response T r i a l : Mean and c o e f f i c i e n t of v a r i a t i o n (CV) f o r ND.-N (mg kg"') and bulk density ( t m" ). 5  NCL-N 6  Date  Bulk density 0-20cm  mg kg"'  %CV  t m"*  %CV  Apr 25  0.8  6.8  3.2 3.7  15.9 6.3 12.1  1.24  May 9  1.31 1.18  5.3 10.5  5.2 8.9 10.2  5.3 20.0 18.5  1.38 1.50 1.34  6.6 11.1 9.1  4.4 6.7  30.5 17.2 29.4 20.5 13.6 7.7  1.14 1.07 0.98  4.4 3.7 7.8 6.7  1984  May 23 June 7 June 20 July 4 1985 May 8 May 22 June 5 June 19  10.5 14.3  July 2 J u l y 16  13.6 10.8  1.11 1.13 1.11  4.8 6.7  60 i n c u r r e d by u s i n g sample date bulk d e n s i t i e s t o c o n v e r t N0 -N 3  from mg k g sampling  - 1  t o kg h a  - 1  was a c c e p t a b l e , because t h e N0 -N 3  e r r o r was g r e a t e r than t h e bulk d e n s i t y measurement  error.  4.2 FERTILIZER NITROGEN RESPONSE TRIAL AND PREPLANT VERSUS SIDEDRESS UREA STUDY  4.2.1  CROP RESPONSE TO FERTILIZER One way a n a l y s i s o f v a r i a n c e showed no s i g n i f i c a n t  d i f f e r e n c e s i n corn y i e l d o r crop N content among any o f t h e f o u r f e r t i l i z e r treatments any o f t h e s i t e s .  A,B o r C.  (0,50,100 and 200 kg h a  - 1  o f N) on  Table 4.4 shows the average  y i e l d s and N c o n t e n t s f o r these t h r e e s i t e s .  Similarly,  corn Mann-  Whitney U t e s t s showed no s i g n i f i c a n t d i f f e r e n c e s between t h e y i e l d s o f crops which had been broadcast f e r t i l i z e d  p r e p l a n t and  those which had been s i d e d r e s s e d when t h e corn was about 30cm tall. ha"  1  The t o t a l dry y i e l d s f o r both treatments and 11.6 t ha"  1  averaged  12.3 t  i n 1984 and 1985 r e s p e c t i v e l y and t h e t o t a l  N uptake was 135 kg ha"» i n both years  (Table 4.4).  Sweet corn does not have t h e same l a r g e demand f o r N as s i l a g e corn, hence t h e l a c k o f response  i n the R e p l i c a t e d  F e r t i l i z e r Response T r i a l and t h e P r e p l a n t Versus  Sidedress  Study may have been due t o t h e adequate supply o f N from the s o i l and t h e s t a r t e r N f e r t i l i z e r .  The t o t a l N uptake by corn  i n t h e R e p l i c a t e d F e r t i l i z e r Response T r i a l was 171 and 143 kg ha  - 1  (Table 4.4) and the average  N0 -N content 3  (0-80cm) at  61  Table 4.4 Replicated f e r t i l i z e r response t r i a l , Preplant versus sidedress urea t r i a l 1984, 1985: Corn data, s i t e means and coefficients of variation.  Replicated f e r t i l i z e r response t r i a l 1984 1985  Corn Yield Fresh Yield (t ha ' ) -  Preplant versus sidedress urea t r i a l 1984  Site A  Site B  Site C  Preplant  1985  Sidedress  Preplant  Sidedress  Stover  Mean CV  37.9 6.5  32.3 17.9  38.9 16.6  36.7 13.9  36.8 11.1  29.2 19.2  29.1 11.3  Cobs  Mean cv  23.9 8.2  26.9 11.2  22.7 16.3  25.2 12.3  24.1  25.8  8.3  11.2  28.2 11.7  Mean  61.8  59.2  61.6  61.9  60.9  55.0  57.3  Stover  Mean CV  8.0 9.1  5.2 13.5  5.8 20.3  6.5 13.8  6.4 7.8  4.8 14.6  4.7 21.3  Cobs  Mean cv  6.1 7.8  5.9 10.2  4.5 25.0  5.3 9.4  5.1 11.8  5.6 1.8  6.2 14.5  Total  Mean  14.1  11.1  10.3  12.5  12.0  11.3  11.9  Stover  Mean cv  97.5 18.6  73.6 10.7  79.2 16.6  54.2 19.0  56.8 19.5  Cobs  Mean cv  73.8 20.3  63.8 N 19.4 contents not 79.3 measured 15.0  57.0 34.2  59.3 19.7  77.2 16.8  81.4 17.3  Total  Mean  171.3  130.6  138.5  131.3  138.2  Total Dry Yield (t ha"' )  N Content (kg ha"' )  143.1  Table 4.5  Replicated F e r t i l i z e r Response T r i a l 1984,1985: S o i l NOj-N, means and c o e f f i c i e n t s o f v a r i a t i o n before planting and a t sidedress time.  S o i l N0j-N kg h a ' -  Date  0-20cm  CV  18.9 37.8  15.2 17.3  1985 Before p l a n t i n g Sidedress time  CV  50-80cm  CV  Total 0-80cm  14.6 23.6  24.1 23.2  57.3 95.8  43.4 40.2  9.2 14.2  89.7 114.6  Site A  1984 Before p l a n t i n g Sidedress tiros  20-50cm  23.9 34.4  18.9 16.2  Site B 10.0 30.7  18.0 16.9  36.4 43.8  17.6 31.4  Planting = 29 May 1984, 8 May 1985. Sidedress = 13 J u l y 1984, 20 June 1985.  63 s i d e d r e s s time was respectively,  95.8  (Table 4.5).  the s o i l N at s i d e d r e s s , ha ), - 1  and 114.6  kg h a  - 1  f o r S i t e s A and B  T h e r e f o r e i t i s q u i t e probable t h a t  the generous  amount of s t a r t e r N (47 kg  and the amount of N m i n e r a l i z e d over the growing  season,  s u p p l i e d s u f f i c i e n t N f o r the c r o p ' s requirements under the p r e v a i l i n g weather and management c o n d i t i o n s .  Dilz  (1981) i n  the Netherlands, showed a s i m i l a r l a c k of reponse when he used s p r i n g b a r l e y as a t e s t crop. N  0 P  and N. „  He found no r e l a t i o n s h i p between  as had been p r e v i o u s l y been found with winter  t  wheat, sugar beet and potatoes.  4.3  MULTIFARM SURVEY  4.3.1  SOIL NITROGEN SUPPLYING CAPACITIES  The M u l t i f a r m Survey p r o v i d e d the g r e a t e s t amount of i n f o r m a t i o n r e l e v a n t t o the p r o j e c t ' s o b j e c t i v e s .  In s p i t e of  the l a r g e amount of v a r i a b i l i t y due t o u s i n g farmers' f i e l d s under a wide range of s o i l c o n d i t i o n s ,  t r e n d s were found  r e l a t i n g the N s u p p l y i n g c a p a c i t y of the s o i l t o s o i l c h a r a c t e r i s t i c s and crop response. Table 4.6 for  shows the M u l t i f a r m Survey's range and mean v a l u e s  s o i l N0 -N and NH*-N sampled a t t h r e e depths at s i d e d r e s s  time.  3  The maximum N0 -N v a l u e i n any depth was 3  50 kg h a , - 1  maximum NH -N v a l u e i n any depth was  16 kg h a  s i t e s with u n u s u a l l y high q u a n t i t i e s  (Appendix 7).  4  - 1  the  except f o r two  Table 4.6  Multifarm T r i a l : S o i l NOj-N and NH^-N a t sidedress time, mean and range over 27 s i t e s .  Depth  NOg-N kg h a  - 1  0 - 20 cm  50 - 80 cm  0 - 80 cm  Mean  22.3  20.9  Range  3.2 - 46.8  0.9 - 49.5  16.3 0.2 - 48.2  4.3 - 141.6  5.1 0.6 - 16.8  7.1 0.5 - 23.9  20.4 2.8 - 37.1  NH -N  Mean  8.2  kg ha"'  Range  0.7 - 25.9  4  20 - 50 cm  59.7  Anomalous s i t e NOj-N kg ha"' NH -N kg h a ' -  +  70.2 8.8  28.3 2.9  38.7 2.5  137.2 14.2  65 4.3.2  BULK DENSITIES OF THE The range and averages  trial  MULTIFARM TRIAL SITES f o r bulk d e n s i t i e s i n the M u l t i f a r m  are shown i n Table 4.7.  The averages  and medians tend t o f a l l c l o s e t o the the o n l y e x c e p t i o n was  show t h a t the means  'Mid-point' of the  ranges;  i n the 20-50cm depth where the v a l u e s  were skewed towards the high end,  c a u s i n g the median bulk  d e n s i t y t o be somewhat h i g h e r than the mean or range  mid-point.  In the M u l t i f a r m T r i a l s i t e bulk d e n s i t i e s were used f o r c o n v e r t i n g N0 -N from mg 3  kg"  1  t o kg h a  i n a s i m i l a r manner t o  - 1  the N M o n i t o r i n g Study. A p a i r e d T - t e s t was  c a r r i e d out comparing N0 -N v a l u e s 3  c a l c u l a t e d u s i n g the i n d i v i d u a l s i t e bulk d e n s i t i e s t o N0 -N 3  c a l c u l a t e d u s i n g the mean bulk d e n s i t y from a l l 28 s i t e s at each depth.  The r e s u l t s showed t h a t the N0 -N v a l u e s c a l c u l a t e d 3  u s i n g i n d i v i d u a l s i t e bulk d e n s i t i e s ,  were s i g n i f i c a n t l y  d i f f e r e n t from v a l u e s c a l c u l a t e d u s i n g a mean bulk d e n s i t y at the 0-20cm depth,  but not at depths 20-50cm, and 50-80cm.  r e s u l t s suggest t h a t where p o s s i b l e ,  plough  should be used f o r c o n v e r s i o n purposes; average  at g r e a t e r depths,  would probably be adequate.  SOIL NITROGEN AND  PREVIOUS CROPPING  The most common crops grown on the s i t e s , corn, were peas, beans and potatoes p r e v i o u s crops were grouped i n t o two ie.  densities  bulk d e n s i t i e s f o r the r e g i o n or the s o i l type under  investigation,  4.3.3  l a y e r bulk  Such  a leguminous crop  (Appendix  the year b e f o r e 6).  When the  c a t e g o r i e s and  (13 s i t e s ) versus potatoes  compared,  (7 s i t e s ) ,  Table 4.7 Multifarm T r i a l : Bulk densities ( t m ) , range and averages. -3  Depth 0 - 20 cm  Bulk Density tm"'  Range  0.76 - 1.43  20 - 50 cm  50 - 80 cm  0.85 - 1.60  0.87 - 1.53  Range  1.10  1.23  1.20  mid-point Mean  1.12  1.24  1.18  Median  1.14  1.31  1.20  t h e r e appeared t o be no r e l a t i o n s h i p between p r e v i o u s crop  and  s o i l N0 -N at s i d e - d r e s s time,  soil  3  p l u s crop N at harvest i e . peas and beans was  ' T o t a l N'.  140 kg ha"  kg ha (CV=59%).  total  The mean T o t a l N f o r  (CV = 52*/.) and f o r potatoes was  1  T h i s apparent  -1  nor p r e v i o u s crop and  144  l a c k of r e l a t i o n s h i p between  p r e v i o u s crop and s o i l N i s not s u r p r i s i n g s i n c e a c c o r d i n g to the UK N Index System <MAFF 1985-86) a l l the crops i n the M u l t i f a r m T r i a l apart from s p r i n g b a r l e y , f e l l category. support  i n t o the Index 1  Furthermore, the high c o e f f i c i e n t s of v a r i a t i o n  the f i n d i n g s by Jungk and Wehrmann (1978) who  found  that  the l a r g e d i f f e r e n c e s i n s o i l N 0 N on s i t e s with the same -  3  p r e v i o u s crop outweighed d i f f e r e n c e s among s i t e s with  differing  p r e v i o u s crops.  4.3.4  SPRING SOIL NITROGEN AND  SOIL PROPERTIES  C o r r e l a t i o n s were c a l c u l a t e d between s o i l N0 -N at s i d e d r e s s 3  time and a l l the s o i l  p r o p e r t i e s determined  and Feed T e s t i n g Laboratory, ie.  V. s i l t ,  sand and c l a y .  by the BCMAF S o i l  p l u s t o t a l s o i l N and s o i l t e x t u r e , Initially,  high c o r r e l a t i o n s were  o b t a i n e d f o r many of the parameters, e s p e c i a l l y s o i l versus o r g a n i c matter. graphs,  showed t h a t most of the c o r r e l a t i o n was  a single outlier of  However a c a r e f u l examination  - 1  3  Mg(5.48 me  of the  accounted  f o r by  N0 -N) and u n u s u a l l y high c o n t e n t s of 3  (167.), P(358 mg  L~  1  lOOmL" ), and Zn(34.3 mg  T h i s s i t e was  3  (Year 2, S i t e 3) which c o n t a i n e d a l a r g e amount  N0 -N (77 kg h a  o r g a n i c matter  N0 -N  1  behind  ), K(3.48 me L"  1  lOOmL" ), 1  1) i n the 0-20cm depth.  a d i s u s e d barn and had p r e v i o u s l y been  manured f o r many years. the  The o u t l y i n g s i t e was e l i m i n a t e d from  data, l e a v i n g 27 s i t e s f o r the M u l t i f a r m Survey  analysis.  Table 4. 8 shows the s i g n i f i c a n t c o r r e l a t i o n s between parameters and s o i l  N0 -N at s i d e d r e s s time. 3  c o r r e l a t e with any s o i l  ORGANIC MATTER AND  soil  NH*-N d i d not  parameters.  TOTAL NITROGEN  Organic matter ranged from 2.2  - 9.5%  i n the 0-20cm depth  although a m a j o r i t y of s i t e s were w i t h i n the narrow 2-5%  range.  S o i l N0 -N d i d not c o r r e l a t e with o r g a n i c matter at any depth. 3  Maximum t o t a l s o i l N was 0.57. i n the 0-20cm depth T o t a l s o i l N was the  (Table 4.8).  p o s i t i v e l y c o r r e l a t e d with o r g a n i c matter i n  0-20cm depth r=0.37(») and i n the 20-50cm depth r=0.32(*>. Many s p r i n g N sampling s t u d i e s have shown l i t t l e ,  i f any  r e l a t i o n s h i p between o r g a n i c matter and N uptake or N mineralized, i s narrow 1984).  e s p e c i a l l y when the range of o r g a n i c matter l e v e l s  (Linden 1984;  S y l v e s t e r - B r a d l e y 1984; Ostergaard,  The reason f o r t h i s l a c k of r e l a t i o n s h i p i s g e n e r a l l y  g i v e n t o be the i n c o n s i s t e n t m i n e r a l i z a t i o n of o r g a n i c N due t o c o n t i n u o u s l y changing s o i l  conditions.  SOIL TEXTURE The M u l t i f a r m T r i a l study area was s i t u a t e d i n the D e l t a r e g i o n o f the F r a s e r V a l l e y where the s o i l t e x t u r e s are mainly silt the  loams t o s i l t y c l a y loams.  The % sand, s i l t  27 study s i t e s ranged from 0-12,  respectively,  and c l a y f o r  58-75, and 19-37%  i n the 0-20cm depth (Table 4.8).  No  significant  Table 4.8  Multifarm T r i a l : Soil parameter ranges and significant correlations at three depths between s o i l characteristics and 'Field Moist' extracted s o i l N0--N at sidedress time.  0 - 2 0 cm Soil Parameter  Range  20 - 50 an r  Range  Salts (E.C.) dS m" 0.32 - 5.0  -  N0 -N kg h a  4.1 - 143.0  0.720 **  0.0 - 92.6  29.0 - 291.0  0.450 **  2.0 - 116.0  -  0.09 - 0.76  % Silt  58-75  % Sand  0-12  % Clay  19 - 37  % Organic matter  2.2 - 9.5  % Total Nitrogen  0.10 - 0.52  pH (H 0)  4.1 - 6.9  t  -1  5  P  jjg  K  mL  -1  me lOOmt,  -1  0.25 - 0.97  Mg me 100 L '  0.65 - 5.67  Ca  me lOOmL  1.83 - 8.0  Na me lOOmL  0.0 - 4.28  Total Cations me lOOraL '  3.79 - 18.0  -  -1  -1  67 - 81 0-14 14 - 31 0.8 - 4.4 0.04 - 0.34  50 - 80 cm  r  Range  -  55-80 0-35 10 - 27 0.7 - 4.6  -0.341 * 0.445 *  0.447  **  3.2 - 6.6  0.24 - 6.1  -0.349  *  0.24 - 9.00  0.808  *•  0.0 - 87.0  0.336  0.878 **  1.4 - 11.6  -  0.73 - 13.63  12.4 - 171.5  -  13.0 - 340.0  -  -  0.59 - 6.67  -  -0.470 **  0.39 - 5.43  -  0.02 - 0.31  3.6 - 6.7  -  r  0.0 - 5.35  -0.406 *  -  2.0 - 61.0 0.08 - 0.76 0.32 - 4.11  *  0.23 - 3.16 0.0 - 7.17  -  -i SO^-S *g mL  10.3 - 136.6  Significance:  -0.369 *  ** = 1%  * = 5%  'Range' = Range of values ewer 27 sites.  70 c o r r e l a t i o n s were found c l a y at any  depth.  between s o i l N0 -N and  Ostergaard  7. sand, s i l t  3  (1985) noted  t h a t although  or  soil  m i n e r a l N i s a f f e c t e d by s o i l t e x t u r e , s i g n i f i c a n t d i f f e r e n c e s are only apparent when t h e r e i s a wide range o f t e x t u r e s . the study  area, the range of s o i l t e x t u r e s was  narrow, i e . the reason  In  relatively  s i l t y loams to s i l t y c l a y loams, t h i s may f o r the l a c k of c o r r e l a t i o n between s o i l  have been  texture  and  s o i l N0 -N at s i d e d r e s s . 3  pH. N0 -N was  p o s i t i v e l y c o r r e l a t e d with pH which ranged from  3  4.1  to 6.9  i n the 0-20cm depth, and  went as low  i n the 20-50 and 50-80cm depths (Table 4.8).  as 3.6  and  This r e s u l t  r e f l e c t s the w e l l known f a v o u r a b l e e f f e c t of higher s o i l nitrification.  The  low pH observed  pH  on  on many of the s i t e s c o u l d  r a i s e d by l i m i n g , t h i s p r a c t i c e would probably s u p p l i e d by the s o i l ,  3.2  be  i n c r e a s e the N  however i t might a l s o i n c r e a s e the  p o t e n t i a l f o r d e n i t r i f i c a t i o n at times when the s o i l  was  very  wet.  MARINE EFFECTS E l e c t r i c a l c o n d u c t i v i t y , Na,  Mg  and S0«-S a l l showed  s i g n i f i c a n t n e g a t i v e c o r r e l a t i o n s with s o i l N0 -N (Table 3  These c o r r e l a t i o n s were caused mainly 2,7,16. Yr.2, conditions.  by f o u r s i t e s  4.8).  (Yr.1,  Sites  S i t e 6) which had been a f f e c t e d by marine These c o n d i t i o n s caused them t o have u n u s u a l l y  l e v e l s of exchangeable i o n s a s s o c i a t e d with sea water and  high  high  71 soluble s a l t s i n the s o i l p r o f i l e s i t e s also displayed s o i l s that, drained  high  (Table 4.8).  Three o f these  NH*-N l e v e l s a t s i d e d r e s s  when unimproved, a r e moderately p o o r l y  ( D e l t a and Ladner s o i l s ) .  and were on to poorly  Such f i n d i n g s suggest  that  f i e l d s with obvious management problems may have t o be t r e a t e d separately,  or excluded from a N f e r t i l i z e r  recommendation  system.  SOIL NITRATE MEASURED BY THE KELOWNA LABORATORY A c o r r e l a t i o n o f the N0 -N i n 'Kelowna' e x t r a c t e d  soils,  3  with t h e N0 -N i n the s o i l s e x t r a c t e d  'Field-Moist',  3  the Kelowna method e x t r a c t e d  showed t h a t  more N0 -N over t h e 0-80cm depth 3  than the F i e l d - M o i s t method (r=0.88 (»*), slope=1.77). the v a r i a b i l i t y  and the d i f f e r e n c e i n magnitude between N0 -N 3  extracted  by t h e two methods, may be due t o the F i e l d  extracted  s o i l s being l e f t  drying.  Some o f  Moist  i n p l a s t i c bags f o r some days b e f o r e  However the h i g h e r l e v e l s found i n the Kelowna  extracted  s o i l s may a l s o have been a product t o some extent of  the d r y i n g ,  grinding  and d i f f e r e n t e x t r a c t i n g procedures used.  A proper comparison o f t h e F i e l d - M o i s t  method and t h e  Kelowna method f o r e x t r a c t i n g s o i l N0 -N would r e q u i r e a p r o j e c t 3  in i t s e l f , noting  however some o f the d i f f e r e n c e s observed were worth  (Table 4.9):  a) The Kelowna N0 -N v a l u e s showed s i g n i f i c a n t 3  correlations  at t h e IV. (»») l e v e l f o r pH a t a l l t h r e e depths (Table 4.9). T h i s was i n comparison t o t h e F i e l d - M o i s t e x t r a c t s which showed t h i s l e v e l o f s i g n i f i c a n c e a t only one o f the t h r e e  depths.  Table 4.9  Multifarm T r i a l : Significant correlations between soil/crop parameters and s o i l NOj-N (sidedress) extracted by the 'Kelowna' and 'Field Moist' methods.  0 - 2 0 cm Kelowna r  Parameter  Field Moist r  50 - 80 cm  20 - 50 cm Kelowna r  Field Moist r  Kelowna r  Field Moist r  Soil pH (HjO)  0.569  **  -  0.546  •*  0.447  **  0.476  0.445  *  Crop - Stalks Fresh yield t ha"'  0.522 *(C)  % Total N  0.771 **(C)  -  0.334 *(L)  0.719 *(C)  0.495 *(C)  0.330 *(L)  0.497 *(C)  0.647 *(C) 0.334 *(L)  0.578 **(C) 0.567 **(C)  0.598 **(C) 0.610 **(C)  0.593 **(C) 0.605 **(C)  Fresh yield t ha"'  0.602 **(L)  0.615 **(L)  0.633 **(L)  % Total N  0.407 *(L)  Total N kg ha"'  0.581 **(L)  0.447 **(L)  0.587 **(L)  0.537 **(L)  0.594 **(L)  0.591 **(L)  Fresh yield t ha '  0.491 *(C)  0.754 **(C)  0.510 *(C)  0.749 **(C)  0.515 *(C)  0.730 **(C)  Total N kg ha '  0.600 **(C) 0.541 *(C)  Total N kg ha ' -  Crop - Cobs 0.571 **(C)  -  0.411 *(L)  0.631 **(C)  _  0.443 *(L)  0.682 **(C)  -  Crop - Whole plant -  -  0.598 **(C) 0.595 **(C)  Significance: ** = 1% * = 5% (L) = Linear correlation (C) = Logarithmic correlation  0.593 **(C) 0.619 **(C)  b> The Kelowna v a l u e s were not c o r r e l a t e d with  electrical  conductivity. c) C o r r e l a t i o n s between Kelowna N0 -N and corn N were 3  s t r o n g e r than between F i e l d Moist N0 -N and corn N. 3  contrast,  In  c o r r e l a t i o n s between Kelowna ND -N and corn y i e l d s 3  were weaker than F i e l d Moist N0 -N and corn y i e l d s 3  (Table 4.9).  A p o s s i b l e e x p l a n a t i o n f o r a l l these f i n d i n g s i s t h a t t h e Kelowna s o i l s underwent a form o f i n c u b a t i o n , or a t l e a s t had a l o n g e r p e r i o d o f m i n e r a l i z a t i o n than the F i e l d Moist e x t r a c t e d soils.  Thus the e f f e c t o f pH on m i n e r a l i z a t i o n and on  nitrification, were d r i e d ,  became more pronounced.  Similarly,  as the s o i l s  t h e r e s u l t i n g n i t r i f i c a t i o n e r a d i c a t e d the n e g a t i v e  c o r r e l a t i o n between s o i l N0 -N and e l e c t r i c a l c o n d u c t i v i t y . 3  The s t r o n g e r r e l a t i o n s h i p between Kelowna N0 -N and corn N, 3  suggests t h a t some form o f i n c u b a t i o n , on t o p o f a simple test,  may improve t h e p r e d i c t i o n o f N uptake,  previously,  N0 -N produced 3  soil  but as mentioned  i n i n c u b a t i o n s does not seem t o be  r e l a t e d w e l l t o N0 -N used f o r crop growth. 3  4.3.5 SPRING SOIL NITROGEN AND CORN RESPONSE T a b l e s 4.10a,b and c show t h e c o r r e l a t i o n s between corn y i e l d parameters and c o n t r o l p l o t m i n e r a l N at s i d e d r e s s time. 'Stalk' y i e l d s i n t h i s d i s c u s s i o n r e f e r to, s t a l k s plus leaves p l u s tops. C o r r e l a t i o n s with both N0 -N and NH -N were c o n s i s t e n t l y 3  4  h i g h e r f o r f r e s h y i e l d s than f o r dry y i e l d s .  The NH -N i n the 4  0-20cm depth was c o r r e l a t e d n e g a t i v e l y with s t a l k and cob, f r e s  74  Table 4.10a  Multifarm t r i a l :  Significant correlations between s o i l N0 -N and NH -N extracted 'Field Moist* and corn yield parameters. S  V  N0,-N extracted 'Field Moist'  Linear Correlation Yield Parameter  # per plot  Crop Part (Mean)  Depth (cm)  Tillers (22)  0-20 0-50 0-80  Stalks (20)  0-20 0-50 0-80  Cobs (23)  0-20 0-50 0-80  0.356 0.396  * *  0.484 (C) 0.529 (C) 0.536 (C)  Stalks (29.9)  0-20 0-50 0-80  0.445 0.489 0.466  ** ** **  0.771 (C) 0.719 (C) 0.647 (C)  ** * *  Cobs (19.6)  0-20 0-50 0-80  0.530 0.620 0.680  ** ** **  0.571 (C) 0.631 (C) 0.682 (C)  ** ** **  Whole Plant (49.5)  0-20 0-50 0-80  0.538 0.608 0.620  0.754 (C) 0.749 (C) 0.730 (C)  ** ** **  Stalks (5.1)  0-20 0-50 0-80  0.393 0.409 0.381  0.567 (C) 0.564 (C) 0.530 (C)  ** * *  Cobs (4.8)  0-20 0-50 0-80  0.365 0.418 0.456  • **  0.471 (C)  *  0-20 0-50 0-80  0.383 0.412 0.408  * ** **  0.505 (C) 0.525 (C) 0.526 (C)  * ** **  * = 5%  NS = Not Significant  (4.1m)  Fresh yield t ha'  1  Dry yield  Logarithmic (C) or Quadratic (Q) correlations R Sig.  t ha ' -  Whole Plant (11.1)  Significance:  ** = 1%  r  0.456 0.503 0.524  -  Sig.  ** ** **  0.573 (C) 0.598 (C) 0.580 (C)  ** ** **  NH -N V  Results for 0-20 cm depth oily r  Sig.  -0.356  *  -0.521  **  -0.460  **  -0.557  **  -0.498  **  -0.352  *  -0.420  *  NS NS NS NS  ** **  • * *  *  • •  *  Table 4.10b  Multifarm t r i a l :  Significant correlations between soil NOj-N and NH^-N extracted 'Field Moist' and corn yield parameters.  NOj-N extracted  Linear Correlation Yield Parameter  % Dry matter  % Total N  Total N kg ha"  Logarithmic (C) or Quadratic (Q) correlations R Sig.  Crop Part (Mean)  Depth (cm)  Stalks (0.17)  0-20 0-50 0-80  Cobs (0.25)  0-20 0-50 0-80  -0.331 -0.386 -0.413  * * *  Stalks (1.00)  0-20 0-50 0-80  0.330 0.334  NS * *  Cobs (1.33)  0-20 0-50 0-80  Stalks (62.8)  0-20 0-50 0-80  0.455 0.472 0.451  ** ** **  Cobs (63.0)  0-20 0-50 0-80  0.447 0.537 0.591  ** ** **  Whole Plant (125.7)  0-20 0-50 0-80  0.499 0.536 0.548  ** ** **  * = 5%  NS = Not Significant  1  Significance:  ** = 1%  r  Sig.  NH^-N  'Field Moist'  NS NS NS  NS NS NS  0.567 (C) 0.610 (C) 0.605 (C)  ** ** **  0.541 (C) 0.595 (C) 0.619 (C)  * ** **  Results for 0-20 cm depth only r  Sig.  76  Table 4.10c  Multifarm t r i a l :  Significant correlations between soil NOj-N and NH^-N extracted 'Field Moist* and corn yield parameters.  NH, -N  NOj-N extracted 'Field Moist*  Linear Correlation Yield Parameter  Relative Yield  Crop Part (Mean)  Depth (cm)  Stalks (0.91)  0-20 0-50 0-80  Cobs (0.87)  0-20 0-50 0-80  0.836 0.393 0.393  * * *  0.458 (Q) 0.487 (Q) 0.505 (Q)  Whole Plant (0.89)  0-20 0-50 0-80  0.394 0.394 0.359  * * *  (O 0.472 (C) 0.472 (C)  Stalks (0.93)  0-20 0-50 0-80  NS NS NS  0.503 (Q) 0.485 (Q) — (Q)  (Fresh)  Relative Yield  Logarithmic (C) or Quadratic (Q) correlations R Sig.  (Dry)  r  -  _  —  Sig.  -  * * * NS  * * * * NS  0-20 0-50 0-80  0.480 0.438 0.400  ** * *  0.506 (C) 0.436 (C) 0.401 (C)  NS NS  Whole Plant (0.91)  0-20 0-50 0-80  0.446 0.408 0.359  ** * *  0.480 (Q) 0.431 (C) 0.400 (C)  NS NS  * = 5%  NS = Not Significant  ** = 1%  r  Sig.  NS NS NS  Cobs (0.92)  Significance:  Results for 0-20 cm depth only  *  *  -0.476  **  -0.407  *  and  dry  that  y i e l d s and  the  with numbers of t i l l e r s ,  t h i s r e s u l t suggest  c o n d i t i o n s which i n h i b i t e d n i t r i f i c a t i o n i n some s o i l s  were a l s o unfavourable f o r corn growth.  NUMBERS OF  TILLERS. COBS AND  Significant  logarithmic  STALKS relationships  (r=0.57**, r = 0.60»*,  r=0.58*») were found when number of t i l l e r s was soil  N0 -N f o r the 3  (Table 4.10a).  depths 0-20,  0-50,  and  p l o t and  soil  per  p l o t was  s i g n i f i c a n t l y correlated  nor  was  y i e l d s and  not  that  stalk.  The  t h e r e was  production.  The  and  e f f e c t of N on  cob  3  positively correlated  available  i n c r e a s e t i l l e r s which y i e l d e d  STALKS. COBS. AND  soil  with t i l l e r s numbers.  4.10a).  dry Dry  3  and  It i s  N c o u l d have been more y i e l d s than t o  WHOLE PLANT  were found t o account f o r  the  g r e a t e s t amount of v a r i a t i o n f o r f r e s h y i e l d s of cobs and f r e s h and  N0  s m a l l e r cobs.  THE  Logarithmic r e l a t i o n s h i p s  with  r e s u l t s showed that  a c o r r e s p o n d i n g i n c r e a s e i n cob  however, that  stalks  N0 -N  e f f i c i e n t l y used to i n c r e a s e i n d i v i d u a l cob  YIELDS OF  number of  with s o i l  The  the  l e v e l of  numbers i s d e l i c a t e l y balanced, e s p e c i a l l y  s i g n i f i c a n t l y and  possible  Table 4.10a.  number of cobs per  r e s p e c t to t i l l e r N was  (•)  found between  3  only 5%  against  respectively  N0 -N, although the  s i g n i f i c a n c e was  the  0-80cm  A s i m i l a r r e l a t i o n s h i p was  number of cobs per  plotted  y i e l d s of s t a l k s and  the  whole p l a n t  both  (Table  y i e l d of cobs showed a l i n e a r c o r r e l a t i o n with  N at s i d e d r e s s time (r=0.46*», 0-80cm).  For  stalks,  the  N0  N0 -N 3  3  i n the top 0-20cm accounted out of a l l t h r e e depths, p r o f i l e produced  f o r the g r e a t e s t amount o f v a r i a t i o n  but f o r cobs N0 -N i n the whole 0-80cm 3  the l a r g e s t c o r r e l a t i o n c o e f f i c i e n t s .  The  c o n c l u s i o n drawn from these l a s t o b s e r v a t i o n s i s t h a t the s t a l k s tended  to o b t a i n a m a j o r i t y o f t h e i r N from the s u r f a c e h o r i z o n ,  w h i l e the cob N, p a r t of which was  t r a n s f e r r e d from s t a l k N,  e x t r a c t e d from a g r e a t e r depth of s o i l .  This i s l o g i c a l  because  the s t a l k s develop f i r s t u s i n g N taken up by r o o t s e x p l o r i n g upper depths o f s o i l , develop,  cobs  (r=0.682«* 0-80cm depth,  l a r g e e x t e n t by the way  NQ -N and f r e s h  weight  3  Table 4.10a) i s caused t o a  a v a i l a b l e N d e l a y s cob m a t u r i t y .  Percent dry matter of cobs was soil  and are t a k i n g up N  depths.  The s t r o n g r e l a t i o n s h i p between s o i l of  the  then, by the time the cobs begin t o  the r o o t s have p e n e t r a t e d deeper  from lower  was  found t o d e c l i n e with  increasing  N 0 N content, or v i c e versa, moisture content i n c r e a s e d -  3  with i n c r e a s i n g s o i l  N 0 - N (Table 4.10a). 3  S i n c e a l l the  sites  were h a r v e s t e d at approximately the same time the l e s s mature cobs c o n t a i n e d p r o p o r t i o n a l l y more water at h a r v e s t .  However,  the e x p e r i m e n t a l s i t e s were h a r v e s t e d at the same time as the farmer's f i e l d ,  thus s i t e s with h i g h e r a v a i l a b l e N w i l l  produce  g r e a t e r f r e s h y i e l d s of sweet corn cobs due t o h i g h e r cob moisture c o n t e n t s .  H a r v e s t i n g the crop at an immature stage  may  a l s o p r o v i d e an e x p l a n a t i o n f o r the c o n s i s t e n t l y weaker r e l a t i o n s h i p s between s o i l soil  N0 -N and dry y i e l d s than between  N 0 - N and f r e s h y i e l d s . 3  been caused  3  T h i s r e s u l t however, may  by the i n c r e a s e d amount of experimental  a l s o have  error  i n c u r r e d i n t h e procedure f o r o b t a i n i n g t h e dry y i e l d s , i e . s e l e c t i n g f i v e p l a n t s from the harvested  area, weighing them,  b r i n g i n g them back t o t h e l a b o r a t o r y , d r y i n g them and then reweighing.  RELATIVE YIELD  R e l a t i v e y i e l d was c a l c u l a t e d a s :  y i e l d o f p l o t not s i d e - d r e s s e d X y i e l d of plot  Relative yields, of  side-dressed  which a r e i n d i r e c t e s t i m a t e s o f the e f f e c t  applied f e r t i l i z e r ,  yields.  100  ranged from 70-120% f o r whole crop f r e s h  Q u a d r a t i c equations  best f i t t e d  r e l a t i o n s h i p s between  s o i l N0 -N and y i e l d s o f dry s t a l k s and f r e s h cobs, and t h e 3  l o g a r i t h m i c equation  best f i t t e d  the r e l a t i o n s h i p between  N0 -N (0-20cm) and r e l a t i v e y i e l d o f dry cobs. 3  for  The c o r r e l a t i o n s  r e l a t i v e y i e l d s were g e n e r a l l y poor (r<0.51) Table 4.10c. The  r e l a t i v e l y high range o f r e l a t i v e y i e l d s  be a r e f l e c t i o n o f t h e low N requirement a l s o i n d i c a t e t h a t added f e r t i l i z e r and  soil  (70-120%) may  o f t h e corn,  i t may  was f r e q u e n t l y o f l i t t l e use  i n some cases may have been d e t r i m e n t a l t o crop growth, eg.  where r e l a t i v e y i e l d was g r e a t e r than curves appeared.  100% and where q u a d r a t i c  The poor response t o f e r t i l i z e r  been due t o t h e s i d e d r e s s i n g technique  may a l s o have  used by t h e custom  80 s i d e d r e s s e r being i n e f f i c i e n t f o r u n i r r i g a t e d corn. was  dropped  discs.  The urea  b e s i d e t h e c o r n p l a n t and covered with s o i l by  Thus t h e shallow i n c o r p o r a t i o n d i d not enable t h e  fertilizer  t o reach moist s o i l and furthermore t h e r e was no r a i n  i n e i t h e r 1984 or 1985 f o r a t l e a s t a month a f t e r s i d e d r e s s i n g (Appendix  1).  Similarly,  t h e manual method o f urea  application  used i n t h e R e p l i c a t e d Response T r i a l and t h e P r e p l a n t versus S i d e d r e s s Urea T r i a l , same reasons,  ie.  wash t h e f e r t i l i z e r  may a l s o have been i n e f f e c t u a l f o r t h e  shallow i n c o r p o r a t i o n and l a c k o f water t o t o t h e r o o t zone.  response t o f e r t i l i z e r  Therefore the lack of  i n these two t r i a l s may not o n l y have  been due t o t h e adequate s o i l N as p r e v i o u s l y suggested, but a l s o due t o t h e poor method o f f e r t i l i z e r  application.  manually  A  comparison  o f t h e corn f e r t i l i z e d  and t h e farmer's corn  fertilized  by machine, may have g i v e n an i n d i c a t i o n o f t h e  e f f i c i e n c y o f t h e manual method, however the farmer's r a t e o f a p p l i c a t i o n d i d not correspond t o any o f the p l o t r a t e s and, as mentioned, t h e machine technique was a l s o i n q u e s t i o n .  STALK. COB. AND WHOLE PLANT NITROGEN Per cent N i n both s t a l k s and cobs showed a l i n e a r r e l a t i o n s h i p with s o i l N0 -N (Table 4.10b). 3  The c o r r e l a t i o n s o f  s o i l N0 -N with t o t a l N (kg ha" ) i n s t a l k s and cobs, 1  3  Dry y i e l d ,  i e . 7. N x  r e f l e c t e d t h e r e l a t i o n s h i p s found with t h e d r y y i e l d s  r a t h e r than with t h e 7.K.  Thus t o t a l N (kg ha" ) i n t h e s t a l k s  t a i l e d o f f with i n c r e a s i n g s o i l  1  N0 -N, w h i l e t o t a l N (kg h a " ) 1  3  i n t h e cobs continued t o i n c r e a s e a c r o s s the range o f s o i l  N0 -N 3  81 v a l u e s measured (Table 4.10b). with s o i l N0 -N, produced  Whole p l a n t N, when c o r r e l a t e d  a l o g a r i t h m i c r e l a t i o n s h i p ; the  3  g r e a t e s t amount o f v a r i a t i o n was accounted 0-80cm depth was c o n s i d e r e d (r=0.55**). found f o r t o t a l cob N c o r r e l a t i o n s , the t o p 0-50cm produced  4.3.6  f o r when N0 -N i n the 3  A s i m i l a r r e s u l t was  however f o r s t a l k s N0 -N i n 3  t h e h i g h e s t r values,  (Table 4.10b).  CORN RESPONSE ON PROBLEM SOILS Three c a t e g o r i e s o f problem s o i l s were i d e n t i f i e d : 1) S i t e s with high e l e c t r i c a l c o n d u c t i v i t i e s  (Year 1,  S i t e s 2,7,16; Year 2, S i t e 7 ) . 2) S i t e s with low pH. selected  The f i v e lowest pH s i t e s were  (Year 1, S i t e s 1,2,5,13,14).  3) S i t e s with n o t i c e a b l e compaction plough  layer  a t t h e base o f t h e  (Year 1, S i t e s 5,14,15; Year 2, S i t e 1).  C o r r e l a t i o n s between s e l e c t e d corn y i e l d parameters and s i d e d r e s s N0 -N were performed 3  with t h e problem s i t e s  excluded.  Table 4.11 shows t h a t e x c l u d i n g t h e s i t e s with high e l e c t r i c a l c o n d u c t i v i t i e s o r low pH strengthened correlations, them.  linear  while e x c l u d i n g t h e compacted s i t e s ,  weakened  When t h e s i t e s with high e l e c t r i c a l c o n d u c t i v i t i e s were  excluded,  t h e r v a l u e f o r t h e l i n e a r c o r r e l a t i o n between  N0 -N (0-80cm) and f r e s h y i e l d o f cobs (r=0.78**), 3  soil  was  s u b s t a n t i a l l y improved over t h e v a l u e f o r a l l t h e s i t e s (r=0.68*«. Table 4.11). conductivity  The f o u r s i t e s with h i g h  ('marine s i t e s ' ) were a l l c h a r a c t e r i s e d by low s o i l  N0 -N l e v e l s a t s i d e d r e s s . 3  electrical  82  Table 4.11  Multifarm T r i a l , problem s o i l s : Selected correlations between crop parameters and s o i l NO.-N, problem s i t e s excluded.  Problem Sites A l l Soils Corn y i e l d  Depth (on)  High E l e c t r i c a l  Excluded  Low pH  Compact  Conductivity  Soils  r  Sig.  r  Sig.  r  Sig.  0.445  ** **  0.475  *  0.317  NS  0.787(C)  * **  0.490  0.771(C)  r  Sig.  Stalks Fresh y i e l d  0-20  t ha"' Cobs Fresh y i e l d t ha '  0-80  0.680 0.682(C)  ** **  0.780 0.773(C)  *+ **  0.762  **  0.644  **  Relative  0-20  0.480  **  0.585  **  0.469  *  0.458  *  0-20  0.538 0.754(C)  **  ** **  0.556  **  0.408  *  0.764(C)  -  Y i e l d Dry Whole plant Fresh y i e l d t ha"'  0.594  Total N kg ha"'  0-80  0.548  **  0.609  **  0.572  **  0.343  NS  Relative Y i e l d Dry  0-20  0.446  **  0.520  **  0.408  *  0.447  *  Significance : ** = 1% * = 5% (C) = Logarithmic c o r r e l a t i o n  NS = Not s i g n i f i c a n t  83  5. NITROGEN FERTILIZER RECOMMENDATIONS IN THE LFV -INTERPRETATION OF THE RESULTS  By combining t h e r e s u l t s from the p r o j e c t ' s f o u r p a r t s , i t i s p o s s i b l e t o p r o v i d e e s t i m a t e s f o r some o f t h e components i n the N Requirement Equation,  and hence shed l i g h t on t h e  q u e s t i o n s posed a t t h e s t a r t o f t h e study. making N f e r t i l i z e r recommendations  With r e s p e c t t o  t h e N Requirement  Equation  can be r e w r i t t e n as:  e <N p r o v i d e d by f e r t i l i z e r e  =  and/or manure)  N Requirement e,(N s u p p l i e d by t h e s o i l )  5.1 NITROGEN REQUIREMENT FOR SWEET CORN The average N Requirement f o r the above-ground p a r t s o f sweet corn was g i v e n i n Table 2.1 (Sec. 2.1.1) t o be 155 kg ha"  1  at a dry cob y i e l d o f 4.1 t h a " . 1  here,  To s i m p l i f y t h e d i s c u s s i o n  N c o n t a i n e d i n corn r o o t s i s not i n c l u d e d i n t h e N  Requirement, however some r e s e a r c h e r s (Magdoff e t a l . 1984) suggest  t h a t the N requirement  account  f o r N i n the roots.  should be i n c r e a s e d by 207. t o  The average value o f 155 kg ha" i s 1  a mean d e r i v e d from a wide range o f corn crops on a v a r i e t y of s o i l types i n v a r i o u s p a r t s o f the USA.  The a c t u a l amount o f N  taken up by a corn crop i n d i f f e r e n t r e g i o n s w i l l o b v i o u s l y vary a c c o r d i n g t o l o c a l s o i l and c l i m a t e c o n d i t i o n s .  The amount of N  taken up by t h e crops i n the M u l t i f a r m Study, i n t h e D e l t a  F i g u r e 5.1  R e l a t i o n s h i p between t o t a l and  cob y i e l d ,  fresh.  corn  nitrogen  85 r e g i o n o f the LFV,  i s shown i n Fig.5.1.  T h i s graph, o f the  r e l a t i o n s h i p between marketable cob y i e l d and t o t a l corn N, can be used t o p r e d i c t approximately how the if the  above-ground  much N would be r e q u i r e d i n  p a r t s f o r a s p e c i f i c cob y i e l d .  a t a r g e t y i e l d was s e t at 20t h a  - 1  example,  f r e s h cobs (4t ha"  graph shows t h a t approximately 125 kg h a  r e q u i r e d i n the whole crop.  For  125 kg h a  - 1  N would  1  dry),  be  i s the amount o f N  - 1  a c t u a l l y found i n a crop which produced a y i e l d of 20 t h a  - 1  f r e s h cobs; s i n c e sweet corn i s prone t o 'luxury uptake', i e . uptake o f N which does not i n c r e a s e y i e l d , i n d i c a t e whether  t h i s f i g u r e does not  l e s s N c o u l d have produced the same y i e l d .  The amount o f N t h a t must be s u p p l i e d t o f u l f i l Requirement,  the N  e i t h e r by the s o i l or by N a d d i t i o n , cannot be  d i r e c t l y determined from Fig.5.1 because t h i s amount depends on the  e f f i c i e n c y o f the crop uptake o f N.  The graph does  indicate  however, the amount o f N which i s adequate f o r a s p e c i f i c of  sweet corn i n the D e l t a r e g i o n o f the LFV.  yield  Therefore, i f a  t a r g e t y i e l d i s given, an approximation t o the N Requirement i s not  too d i f f i c u l t  to obtain.  The v a l u e o f 125 kg h a Multifarm t r i a l kg h a " , 1  - 1  f o r 4 t ha"  1  dry cobs i n the  i s r a t h e r l e s s than the p u b l i s h e d averages  T a b l e 2.1,  (155  Sec.2.1.1), t h i s r e l a t i v e l y low N uptake  c o u l d have been due t o poor s o i l  conditions.  A number o f  f a c t o r s which i n h i b i t e d corn use of N were seen i n the f i e l d , the  most obvious being s o i l compaction which i n h i b i t e d  p e n e t r a t i o n on many s i t e s . compacted  root  The m a j o r i t y o f corn r o o t s on  s i t e s were found i n the top 25cm, thus water and  86 n u t r i e n t uptake would have been l i m i t e d . of  both s o i l N and f e r t i l i z e r  soil  The uptake e f f i c i e n c y  N may be i n c r e a s e d by improved  management.  5.2 NITROGEN SUPPLIED BY THE SOIL  5.2.1 SOIL SAMPLING  VERSUS A NITROGEN INDEX SYSTEM  S o i l N0 -N sampling 3  seems t o be more u s e f u l than a N Index  System i n the area o f study.  None o f the groupings  which a r e  used t o p r e d i c t s o i l N supply i n the E n g l i s h N Index System (MAFF 1985-86) showed up i n t h i s study, soil  i e . p r e v i o u s cropping,  t e x t u r e and manure i n f l u e n c e ; t h i s was due t o the narrow  range o f crop types, and s o i l t e x t u r e , and a l s o because manure i s not r o u t i n e l y used i n the D e l t a M u n i c i p a l i t y area.  It i s  p o s s i b l e however, t h a t the i n f l u e n c e o f manure was shown on the anomalous s i t e  (Year 2, S i t e 3) which had high o r g a n i c  and a high s p r i n g s o i l N0 -N content. 3  matter  The s i t e was s i t u a t e d  behind a d i s u s e d d a i r y barn and had r e c e i v e d many years o f manure a p p l i c a t i o n .  However, i t was not p o s s i b l e t o s e p a r a t e  the e f f e c t s o f manure on t h i s s i t e ,  from the e f f e c t s due t o  ploughing out the 30-year o l d p a s t u r e two years b e f o r e the study. The one other f a c t o r t h a t i s f r e q u e n t l y used Budget systems i s o r g a n i c matter. was found between o r g a n i c matter  No s i g n i f i c a n t and s o i l  i n N Index or relationship  N0 -N a t s i d e d r e s s 3  time and a n e g a t i v e r e l a t i o n s h i p was even found with t o t a l N and soil  N0 -N (Sec. 4.3.4). 3  87 An estimate o f m i n e r a l i z a t i o n was c a l c u l a t e d u s i n g t h e p l o t s without  s i d e d r e s s N and the f o l l o w i n g assumptions; 1) Most  m i n e r a l i z a t i o n i n the r e g i o n o f study occurs i n t h e 0-50cm depth.  2) There was no r e s i d u a l N from t h e p r e v i o u s year i n t h e  top 0-50cm. 3) N i n t h e r o o t s was i n s i g n i f i c a n t .  MINZN =  (N (kg h a " ) i n cobs «- s t a l k s ) + 1  ( S o i l N0 -N + NH*-N a t h a r v e s t 3  (kg h a " ) 0-50cm) 1  s t a r t e r N x ( e f f i c i e n c y o f s t a r t e r = 0.7)  A weak p o s i t i v e r e l a t i o n s h i p  (r=0.45*) was found  o r g a n i c matter and m i n e r a l i z a t i o n .  between  However, when m i n e r a l i z a t i o n  as a p r o p o r t i o n o f o r g a n i c matter content was p l o t t e d a g a i n s t o r g a n i c matter,  ( F i g . 5 . 2 ) , t h e graph showed t h e p r o p o r t i o n o f  o r g a n i c matter m i n e r a l i z e d t o be i n v e r s e l y r e l a t e d t o o r g a n i c matter content Broadbent  (r=-0.51»»); a s i m i l a r f i n d i n g was recorded by  (1984).  The reason  f o r t h i s inverse relationship  c o u l d be t h a t t h e higher o r g a n i c matter l e v e l s were a r e s u l t o f poor s o i l c o n d i t i o n s which i n h i b i t e d m i n e r a l i z a t i o n , eg. poor drainage, suggestion  s o i l a c i d i t y and/or marine i n f l u e n c e s . was supported  This  by the lowering o f t h e r value t o -  0.41(») f o r t h e graph i n Fig.5.2 when t h e 'marine s i t e s ' were excluded.  One n o t a b l e e x c e p t i o n t o t h i s n e g a t i v e  relationship  was again shown by t h e anomalous s i t e which d i s p l a y e d an u n u s u a l l y high o r g a n i c matter l e v e l and a c o r r e s p o n d i n g l y s o i l N0 -N content a  a t s i d e d r e s s time.  high  The s i t e had been i n  p a s t u r e f o r 30 years and was ploughed out only two years  before  N MINERALIZED  4  O.M. CONTENT(0-50cm) 16.0  X  '°  n  ~»  0  1  1  1  1  100  1  200  ORGANIC MATTER thd'  1  300  (0'50cm)  F i g u r e 5.2 R e l a t i o n s h i p between m i n e r a l i z a t i o n as a p r o p o r t i o n o f o r g a n i c matter and o r g a n i c matter  (0-50cm).  1  89 the  study, i t a l s o had high pH and good drainage.  Therefore  s i t e h i s t o r y seems t o be an important c o n s i d e r a t i o n when e v a l u a t i n g the p o t e n t i a l e f f e c t o f o r g a n i c matter on soil  available  N. I t appears o v e r a l l ,  Delta Municipality,  t h a t i n a s m a l l area of the LFV such as  a s p r i n g s o i l t e s t would be of more use than  a N Index System f o r improving N f e r t i l i z e r  5.2.2  recommendations.  IMPLEMENTING A SPRING SQIL TEST  DEPTH OF SAMPLING The r e s u l t s o f the M u l t i f a r m T r i a l for to  showed the c o r r e l a t i o n s  response curves of s t a l k y i e l d s and s t a l k N with s o i l  N0 -N, 3  be g r e a t e s t i n the 0-20cm depth, and f o r cob y i e l d s and cob N  with s o i l N0 -N, t o be g r e a t e s t i n the 0-80cm depth 3  (Sec.4.3.5).  These r e s u l t s cause the q u e s t i o n of sampling depth t o be unclear.  I f the sampling method uses c o r r e l a t i o n s with s t a l k or  whole p l a n t y i e l d s , sufficient.  sampling t o 20cm would seem t o be  In f a c t sampling t o t h i s depth i s probably more  d e s i r a b l e i n most cases because i t i s the e a s i e s t and cheapest depth t o sample.  However, i f recommendations were made u s i n g  c o r r e l a t i o n s i n v o l v i n g cob y i e l d s or cob N contents, sampling t o a depth g r e a t e r than 20cm would be more a c c u r a t e .  Finances  permitting,  i e . sampling  to  a compromise may  be the best s o l u t i o n ,  a depth o f 50 or 60cm as i n many of the European  countries.  Obviously the suggested sampling depths here are s p e c i f i c t o sweet corn i n the D e l t a r e g i o n ,  and would be d i f f e r e n t f o r  90 d i f f e r e n t crops and a l s o f o r d i f f e r e n t s o i l  conditions.  TIME OF SAMPLING As p r e v i o u s l y mentioned the best time f o r sampling close to f e r t i l i z i n g environmental of  as p o s s i b l e i n order t o  minimize  i n f l u e n c e s on the measured m i n e r a l N.  the N M o n i t o r i n g Study  i s as  The  results  (Sec. 4.1.3) supported t h i s s u g g e s t i o n  by showing the s o i l N0 -N c o n t e n t s t o i n c r e a s e at a constant 3  r a t e between the temperatures  of 5 and 20°C and u n t i l the crop  began t o take up s o i l N, g e n e r a l l y 5-6 a week or two b e f o r e s i d e d r e s s i n g . be p o s s i b l e t o p r e d i c t s o i l  weeks a f t e r p l a n t i n g  and  T h e r e f o r e , although i t may  N0 -N at s i d e d r e s s from  soil  3  measurements taken e a r l i e r i n the season combined with a knowledge of s o i l  temperature,  from the farmer's p e r s p e c t i v e i t  i s e a s i e r t o watch the crop and sample a couple of weeks b e f o r e sidedressing, Sampling  i e . when the crop i s almost 30cm t a l l . c l o s e to f e r t i l i z i n g  would mean t h a t the  time f o r a n a l y s i s and output of subsequent  turnaround  fertilizer  recommendations would have t o be minimal.  S i n c e the N0 -N t e s t  need not n e c e s s a r i l y be extremely  a f i e l d t e s t such  the Merck quick t e s t  precise,  3  (Hunt et al.1979; Scharpf and  Grantzau  1985)  or the s o i l N0 -N e l e c t r o d e c o u l d be employed.  5.2.3  ESTIMATING SOIL AVAILABLE NITROGEN USING HARVEST-TIME  3  MEASUREMENTS As p r e v i o u s l y mentioned, e s t i m a t e s of a v a i l a b l e s o i l N i n humid r e g i o n s are most a c c u r a t e when based on two  components;  as  1) A measure of m i n e r a l N i n the p r o f i l e on a s p e c i f i c date 2) An e s t i m a t e of N m i n e r a l i z e d  over the growing season.  Component (1) i n the study here, was at  sidedress  time.  Component  N0 -N and  simply s o i l  (2) can  NH -N  a  be estimated from  r e s u l t s i n a number of ways, the method d e s c r i b e d being j u s t one.  and,  the  i n Sec.  I t must be remembered at t h i s p o i n t ,  4  5. 2. 1  that a l l  e s t i m a t e s of m i n e r a l i z a t i o n here are i n d i r e c t e s t i m a t e s ( i e . extrapolated  from the s o i l  of N m i n e r a l i z e d extent  by  The  130  kg ha" , 1  (Appendix 6).  and  t h a t the amount  to a g r e a t e r  or l e s s e r  crop.  mean amount of N m i n e r a l i z e d ,  somewhat higher kg ha"  crop data),  been i n f l u e n c e d  the growing corn  5.2.1, was sites,  has  and  as determined i n  with a range of 40-275 kg h a  kg ha"  and  1  over  - 1  These v a l u e s f o r m i n e r a l i z a t i o n  than the mean of 80  Sec.  are  range of 30-140  recorded by Wehrmann et a l . (1982) on German s i t e s  1  growing winter wheat.  The  d i f f e r e n c e may  d i f f e r e n t environmental and  simply be due  crop c o n d i t i o n s ,  to  however, the  v a l u e s are p o s s i b l y o v e r e s t i m a t e s because the assumption there  27  was  no r e s i d u a l N i n the 0-50cm depth may  For example, S i t e B i n the N M o n i t o r i n g s u b s t a n t i a l amounts of both N 0 - N and 3  A f u r t h e r sampling i n the earlier,  be  LFV that  correct.  contained  NH -N j u s t a f t e r p l a n t i n g . 4  trial,  at p l a n t i n g  or  would have been able to determine the v a l i d i t y of  assumption. estimating  The soil  r e s i d u a l N would not N i f i t was  i n e v i t a b l y v a r i e s due weather  Multifarm  Study  not  conditions.  consistent  t o cropping  the  the  cause a problem i n year to year but i t  r o t a t i o n s and  varying  soil  and  For t h e purpose o f e s t i m a t i n g a v a i l a b l e s o i l N using the two component approach, another  e s t i m a t e o f m i n e r a l i z a t i o n can be  o b t a i n e d from t h e r e l a t i o n s h i p between M i n e r a l i z a t i o n , as d e f i n e d i n Sec. 5.2.1, and m i n e r a l N a t s i d e d r e s s time as seen i n F i g . 5.3.  The equation f o r t h e l i n e a r  i s y = 66.5 + 1.3x (r=0.59**).  (0-50cm)  relationship  From t h i s equation t h e amount of  N m i n e r a l i z e d between s i d e d r e s s and harvest can be c a l c u l a t e d . The i n t e r c e p t on t h e y - a x i s ( i e . 66.5 kg h a  - 1  ) corresponds t o  the q u a n t i t y o f N i n t h e s o i l and crop at h a r v e s t when t h e r e was zero N0 -N a t s i d e d r e s s time. 3  T h i s amount o f m i n e r a l i z a t i o n can  be c o n s i d e r e d as t h e 'Basal M i n e r a l i z a t i o n ' , u n r e l a t e d t o t h e amount o f N found  at s i d e d r e s s time.  I f 'x' i s taken as the  mean amount o f m i n e r a l N (NH*-N + N0 -N, 0-50cm) found a t 3  s i d e d r e s s time on t h e 27 s i t e s ,  i e . 57 kg ha * (Sec.4.3.1),  a d d i t i o n a l 1.3 X 57 = 74.1 kg h a  -  - 1  an  m i n e r a l N above t h e b a s a l  q u a n t i t y becomes a v a i l a b l e between s i d e d r e s s and h a r v e s t  time.  T h e r e f o r e the e s t i m a t e o f m i n e r a l i z a t i o n d e r i v e d t h i s way i s approximately ha of  - 1  140 kg h a  - 1  (66.5 + 74.1) i n comparison t o 130 kg  d e r i v e d by t h e method i n Sec.5.2.1.  Both these  estimates  m i n e r a l i z a t i o n however have been d e r i v e d u s i n g measurements  taken a t h a r v e s t - t i m e ;  i n order t o make N f e r t i l i z e r  recommendations i t would be d e s i r a b l e t o be a b l e t o p r e d i c t a v a i l a b l e N from s i d e d r e s s - t i m e measurements.  MINERALIZATION (kg ha"') 300-,  1  1  0  i  50  1  100  SOIL N0 -N+ NH -N kg ha" (0"50cm) AT SIDEDRESS 1  3  4  F i g u r e 5.3 R e l a t i o n s h i p between m i n e r a l i z a t i o n and s o i l mineral nitrogen  (0-50cm) a t s i d e d r e s s  94 5.2.4  PREDICTING SOIL AVAILABLE NITROGEN FROM NITRATE FOUND AT SIDEDRESS TIME The  graph of m i n e r a l i z a t i o n versus mineral  which was  used t o estimate  N at s i d e d r e s s ,  b a s a l m i n e r a l i z a t i o n i n Sec.5.2.3,  c o u l d a l s o be used f o r p r e d i c t i o n purposes, however the r was  only 0.59(*»).  By comparing r e g r e s s i o n values,  t h a t the r e l a t i o n s h i p between m i n e r a l N and N at harvest, calculations  was  s t r o n g e r when NH -N was  (Table 5.1).  T h i s may  be due  i t was  found  t o t a l crop p l u s  omitted  4  value  to the  from  soil  the  sites  c o n t a i n i n g s i g n i f i c a n t q u a n t i t i e s of NH -N being  anomalies by  being e i t h e r p o o r l y d r a i n e d and/or i n f l u e n c e d by  marine  4  conditions.  When the marine s i t e s were excluded,  r e l a t i o n s h i p between s o i l  N0 -N at s i d e d r e s s and  s o i l N0 -N at h a r v e s t  f u r t h e r improved  3  although  3  was  the most c o r r e c t d e t e r m i n a t i o n s  the crop N p l u s  (Table 5.1).  Hence,  of N m i n e r a l i z e d  should  c o n t a i n NH*-N, c a l c u l a t i o n s c o n s i d e r i n g only N0 -N are used here 3  due  to the s i m p l i f i c a t i o n ,  and  greater confidence  found i n the  p r e d i c t i o n s when t h i s i s done. Table 5.1  shows the r values,  i n t e r c e p t s and  c o r r e l a t i o n s between s i d e d r e s s N0 -N and 3  harvest at the t h r e e d i f f e r e n t depths. taken up by the crop was ha  - 1  X 70'/., t h i s value was  s l o p e s f o r the  corn p l u s s o i l The  N0 -N at 3  amount of s t a r t e r N  assumed to be 33 kg h a , - 1  i e . 47  s u b t r a c t e d from the corn N.  The  r e l a t i o n s h i p s are seen t o i n c r e a s e i n s t r e n g t h as more of p r o f i l e N0 -N i s considered, 3  t h i s i m p l i e s t h a t the corn  took up N0 -N from as deep as the 0-80cm depth. 3  from depth was  kg  the  roots  Crop uptake  a l s o i m p l i e d by p a i r e d T - t e s t s comparing  soil  95  Table 5.1  Multifarm T r i a l : Estimating N supplied by the s o i l . Linear regressions between crop N plus s o i l mineral N a t harvest and s o i l mineral N a t sidedress. (Mineral N = NOyN + NH^-N o r just NO,-N)  NCL-N and NH, -N considered  NOj-N considered  Depth (cm)  r  r  Sig.  Intercept  Slope  r  r  Sig.  A l l Sites  Intercept  Slope  0-20  0.467  0.218  **  71.5  1.6  0.543  0.295  **  73.3  1.7  0-50  0.592  0.350  **  66.5  1.3  0.623  0.388  **  69.3  1.3  0-80  0.685  0.469  **  67.6  1.1  0.716  0.513  **  68.9  1.2  Excluding Marine S i t e s 0-20  0.588  0.346  **  49.0  2.2  0.635  0.403  **  59.9  2.1  0-50  0.674  0.454  **  38.2  1.7  0.705  0.497  **  48.5  1.6  0-80  0.739  0.546  **  44.4  1.3  0.787  0.619  **  47.3  1.4  Significance : * * = ! %  * = 5%  NS = Not s i g n i f i c a n t  96 N0 -N a t s i d e d r e s s and h a r v e s t . 3  The s o i l N0 -N c o n t e n t s a t 3  h a r v e s t i n both the 0-50cm depth and t h e 0-80cm depth were s i g n i f i c a n t l y d i f f e r e n t from those a t s i d e d r e s s ( N O 3 - N 0-50cm; s i d e d r e s s = 43.2, h a r v e s t = 23.7. 59.5,  h a r v e s t = 27.5.  kg h a : 1  0-80cm; s i d e d r e s s =  Appendix 14a and c ) .  The s t r o n g e s t c o r r e l a t i o n i n Table 5.1 was between s o i l N a t s i d e d r e s s (0-80cm> and crop N p l u s s o i l N0 -N 3  h a r v e s t ) when t h e marine s i t e s were excluded  N0 3  (0-80cm,  (r =0. 62*»). a  The  amount o f N s u p p l i e d by t h e s o i l can be p r e d i c t e d from t h e equation f o r t h i s c o r r e l a t i o n  (Fig.5.4) i e . y = 47.3 + 1.4x.  T h i s equation e s t i m a t e s t h a t f o r every kg h a * N0 -N (0-80cm) -  3  found i n t h e s o i l a t s i d e d r e s s , 47.3 +1.4 times t h i s amount, can be expected  i n t h e s o i l and crop a t h a r v e s t .  The equation,  i n s p i t e o f being s p e c i f i c t o a p a r t i c u l a r crop and r e g i o n , c o u l d be very u s e f u l f o r LFV N recommendations by accounting f o r the N s u p p l i e d by t h e s o i l . As p r e v i o u s l y d e s c r i b e d , t h e i n t e r c e p t s shown i n Table 5. 1 p r o v i d e an e s t i m a t e o f b a s a l m i n e r a l i z a t i o n .  The i n t e r c e p t  changes n o t i c e a b l y from t h e 0-20cm depth t o t h e 0-50cm depth but b a r e l y changes between t h e 0-50 and 0-80cm depths,  this  suggests  t h a t more m i n e r a l i z a t i o n o c c u r r e d i n t h e s u r f a c e 0-50cm than i n the deeper h o r i z o n . be expected  The s l o p e shows how much N a t h a r v e s t can  f o r every kg ha"  1  o f N0 -N found a t s i d e d r e s s time. 3  The s l o p e v a l u e s decrease down t h e p r o f i l e ,  a r e s u l t which i s  probably due t o t h e two i n s e p a r a b l e reasons mentioned p r e v i o u s l y ie.  a) more m i n e r a l i z a t i o n o c c u r r e d h i g h e r up t h e p r o f i l e , and  b) t h e crop took up m i n e r a l N from the whole 0-80cm depth.  SOILNO3N  (0-80cm) -f  CROP N kg ho"' AT HARVEST  300-r  F i g u r e 5.4 R e l a t i o n s h i p between s o i l n i t r a t e  (0-80cm)  plus crop n i t r o g e n a t harvest and s o i l n i t r a t e (0-80cm) a t s i d e d r e s s .  98 5.3 EFFICIENCY OF CROP UPTAKE OF SOIL MINERAL NITROGEN (e,) The r e s u l t s o f the M u l t i f a r m T r i a l  show t h a t a reasonable  e s t i m a t e o f N p r o v i d e d by the s o i l can be made from N0 -N i n the 3  s o i l a t s i d e d r e s s <r =0.62** f o r the 0-80cm depth Table 5.1). 8  However t h i s e s t i m a t e does not i n d i c a t e how much o f the s o i l N i s a v a i l a b l e t o the crop, i e . the e f f i c i e n c y o f crop uptake o f s o i l N. An e s t i m a t e f o r e i can be made from the r e l a t i o n s h i p between crop N uptake and t o t a l s o i l  p l u s crop N at h a r v e s t ( F i g . 5 . 5 ) .  T h i s estimate assumes t h a t no N was l o s t from the 0-80cm d u r i n g the growing season.  The s l o p e o f the graph  0.5, can be taken as the average corn i n the M u l t i f a r m T r i a l .  depth  i n Fig.5.5,  uptake e f f i c i e n c y f o r sweet  T h i s value i s somewhat lower  than  the e s t i m a t e of 70% taken by Magdoff e t a l . (1984) f o r s i l a g e corn, i t p o s s i b l y r e f l e c t s a l a c k o f water due t o the u n u s u a l l y dry summers and the shallow r o o t p e n e t r a t i o n caused  by s o i l  compaction. Another e s t i m a t e o f e the R e p l i c a t e d F e r t i l i z e r response e»  to f e r t i l i z e r .  t  c o u l d have been made from r e s u l t s i n Response T r i a l  had t h e r e been a  I f a more p r e c i s e estimate than 50% f o r  i s d e s i r e d , f u r t h e r experiments  would be necessary.  i f t h i s e s t i m a t e i s c o n s i d e r e d t o be reasonable,  However,  t h r e e o f the  components o f t h e N Requirement Equation are now s a t i s f i e d , i e . Crop N Requirement, e», and N s u p p l i e d by the s o i l . determine it  In order t o  the f e r t i l i z e r  component o f the N Requirement Equation  i s necessary t o f i r s t  estimate the e f f i c i e n c y f a c t o r f o r the  a p p l i e d N, i n t h i s case urea.  F i g u r e 5.5  R e l a t i o n s h i p between crop n i t r o g e n uptake and at  t o t a l crop p l u s s o i l n i t r o g e n (0-80cm) harvest.  100 5.4  EFFICIENCY OF CROP UPTAKE OF FERTILIZER  (e > e  The e f f i c i e n c y f a c t o r f o r s t a r t e r f e r t i l i z e r , was  the l i t e r a t u r e v a l u e of 70%.  used above,  However, t h r e e out of the f o u r  p a r t s of t h i s study emphasised s e r i o u s l i m i t a t i o n s t o the e f f i c i e n c y of s i d e d r e s s a p p l i e d f e r t i l i z e r . An e s t i m a t e of the e f f i c i e n c y of s i d e d r e s s f e r t i l i z e r was  e  3  calculated  =  (e ) 3  as:  Y i e l d of Corn N on f e r t i l i z e d  plot -  Y i e l d of Corn N on c o n t r o l p l o t Amount of f e r t i l i z e r  The f e r t i l i z e r (Appendix  N s i d e d r e s s e d = 135 kg h a  e f f i c i e n c y v a l u e s ranged  from  -26%  N  - 1  to  52%  6), they were probably low due t o the u n u s u a l l y dry  summers and a l s o the i n e f f i c i e n t f e r t i l i z i n g sidedress f e r t i l i z e r  techniques.  A  e f f i c i e n c y value of 50% w i l l be used i n  f o l l o w i n g c a l c u l a t i o n s even though t h i s i s at the upper end  of  the range of v a l u e s c a l c u l a t e d e x p e r i m e n t a l l y . R e l a t i o n s h i p s between f e r t i l i z e r are sometimes observed.  Dstergaard  e f f i c i e n c y and s o i l t e x t u r e (1985) on some Danish  soils  found a r e l a t i o n s h i p between % sand and the e f f i c i e n c y of fertilizer e  e  use.  In the study here,  and s o i l t e x t u r e was  the only c o r r e l a t i o n between  a weak r e l a t i o n s h i p with s i l t  0.40*), s u g g e s t i n g t h a t s i l t y s o i l s somehow a i d e d utilization. silty  I t i s p o s s i b l e t h a t i n the two  (r =  fertilizer  years o f study,  the  s o i l s were most e f f i c i e n t at p r o v i d i n g water t o the p l a n t s  and thus i n d i r e c t l y improved use of  fertilizer.  101  5.5  NITROGEN SUPPLIED BY FERTILIZER AND/OR MANURE From t h e r e s u l t s o f t h e p r o j e c t ,  t h r e e approaches can be  taken t o e s t i m a t e t h e 'Added N' component i n t h e N Requirement equation: 1) Using t h e components o f t h e N Requirement Equation. 2) Using t h e l i n e a r  r e l a t i o n s h i p between s o i l  N0 -N and crop 3  response. 3) Using the l o g a r i t h m i c r e l a t i o n s h i p between s o i l N0 -N and 3  crop response  p l u s t h e Cate-Nelson  procedure  the data i n t o r e s p o n s i v e and non r e s p o n s i v e  5.5.1  of s p l i t t i n g sites.  ESTIMATING FERTILIZER REQUIREMENTS USING THE NITROGEN REQUIREMENT EQUATION T h i s approach uses t h e graphs i n F i g s . 5. 1 and 5. 4. t o  estimate t h e N Requirement Equation components.  To o u t l i n e the  approach an example u s i n g a t a r g e t y i e l d o f 20 t ha marketable cob y i e l d  cobs s h a l l be taken.  -1  of  From the r e l a t i o n s h i p between  and t o t a l p l a n t N, o r N Requirement  ( F i g . 5.1),  i t was  a l r e a d y noted t h a t a cob f r e s h y i e l d o f 20 t h a * r e q u i r e s -  approximately 40 kg h a  - 1  125 kg ha" N i n t h e whole p l a n t . 1  I f f o r example,  o f N0 -N i s found i n t h e s o i l a t s i d e d r e s s , the 3  e q u a t i o n f o r t h e c o r r e l a t i o n between N0 -N (0-80cm) a t s i d e d r e s s 3  and t o t a l crop p l u s s o i l N0 -N (0-80cm) a t h a r v e s t 3  = 47.3 + 1.4x) p r e d i c t s t h a t approximately a v a i l a b l e by t h e s o i l . 50 kg h a  - 1  Ife  t  100 kg h a " N i s made  i s taken as 50%,  N i s s u p p l i e d by t h e s o i l .  ( F i g . 5.4, y 1  then 100 X 0. 5 =  Therefore, t h e f e r t i l i z e r  102 or  manure c o n t r i b u t i o n must be the N Requirement  l e s s the N s u p p l i e d by the s o i l N)/e .  With e  e  (50 kg ha~ ), i e . (75 kg 1  e s t i m a t e d at 50%,  e  (125 kg h a ha  the amount o f f e r t i l i z e r  manure N r e q u i r e d t o produce a f r e s h cob y i e l d o f 20 t ha" s o i l N0 -N at s i d e d r e s s (0-80cm) i s 40 kg h a " , 1  3  150 kg ha~ .  N)  - 1  - 1  or 1  when  w i l l be 75/0.5 =  An approach such as t h i s i s easy t o apply, however  1  f u r t h e r e x p e r i m e n t a t i o n would be r e q u i r e d t o v e r i f y relationships,  the  e s p e c i a l l y when s o i l s and growing season weather  c o n d i t i o n s vary.  5.5.2  ESTIMATING FERTILIZER REQUIREMENTS USING THE LINEAR AND  LOGARITHMIC RELATIONSHIPS BETWEEN SOIL NITRATE AND  CROP  RESPONSE Two  d i f f e r e n t types of crop response t o B o i l  N0 -N were 3  found i n the p r o j e c t a) L i n e a r and b) L o g a r i t h m i c .  After  e x c l u d i n g s i t e s with high e l e c t r i c a l c o n d u c t i v i t i e s  (marine  i n f l u e n c e d ) a s t r o n g l i n e a r response was  found between  marketable cob y i e l d s and s o i l N0 -N, 0-80cm (r =0.78 3  Sec. 4. 3. 6).  The s t a l k ,  and whole crop y i e l d s i n c o n t r a s t ,  showed l o g a r i t h m i c responses.  These two types o f response  suggested t h a t two d i f f e r e n t approaches c o u l d be taken t o o b t a i n fertilizer  requirements from the crop response t o s o i l  1) S o i l N0 -N and l i n e a r crop response. 3  2) S o i l N0 -N and l o g a r i t h m i c crop response. 3  N0 -N: 3  103  ESTIMATING FERTILIZER REQUIREMENTS USING THE LINEAR RELATIONSHIP BETWEEN SOIL NITRATE AND CROP RESPONSE F i g u r e 5.6 shows t h e r e l a t i o n s h i p between s o i l N0 -N (0-80 3  cm) and cob f r e s h y i e l d with marine s i t e s excluded. regression  line fitting  From t h e  t h e r e l a t i o n s h i p i t can be p r e d i c t e d  t h a t a s o i l N0 -N (0-80cm) content at s i d e d r e s s o f 40 kg h a  - 1  3  ( p l u s s t a r t e r N) w i l l r e s u l t i n a f r e s h cob y i e l d o f approximately 17 t h a " . 1  aimed f o r , and e  I f a t a r g e t y i e l d of 20 t h a i s 1 -  i s taken as 50%, the s i d e d r e s s  e  fertilizer  requirement can be d e r i v e d from t h e r e l a t i o n s h i p between cob y i e l d and whole p l a n t N ( F i g . 5.1, additional 3 t h a 16.2)  - 1  y = 19.3 + 5.4x).  The  o f cobs thus r e q u i r e s 35.5 kg N (19.3 +  which can be s u p p l i e d by 35.5/0.5 = approx. 70 t ha"  fertilizer to t h i s ,  N at sidedress.  I f t h e 47 kg ha"  the t o t a l f e r t i l i z e r  Hence, from t h e l i n e a r f r e s h cob y i e l d , for  a specific  has  no other  what extent  1  s t a r t e r N i s added  requirement i s almost 120 kg h a . 1 -  r e l a t i o n s h i p betweem s o i l N0 -N and 3  a farmer can be shown the y i e l d he can expect  s o i l N0 -N content a t s i d e d r e s s . 3  limiting  conditions,  If his field  the farmer can then decide t o  he wishes t o improve h i s y i e l d above t h a t  s o l e l y with s o i l  1  obtained  and s t a r t e r N.  Both t h e 'N Requirement E q u a t i o n ' approach and the 'Linear R e l a t i o n s h i p ' approach f o r e s t i m a t i n g  the F e r t i l i z e r N  Requirement have appeared t o be q u i t e p r e c i s e . variability  shown both i n o b t a i n i n g  producing r e l a t i o n s h i p s between corn  However the  s o i l N0 -N values, 3  response and s o i l  and i n N0 -N, 3  COB YIELD, FRESH (tha") 3 On  F i g u r e 5.6 R e l a t i o n s h i p between cob y i e l d , soil nitrate  f r e s h and  (0-80cm) a t s i d e d r e s s .  105 suggest t h a t such p r e c i s e methods f o r p r e d i c t i n g f e r t i l i z e r requirements may The cob  r  B  not be  f o r the r e l a t i o n s h i p between s o i l N0 -N (0-80cm) and 3  fresh yield  (marine s i t e s excluded) was  generally acceptable still line  practical.  0.61»» which i s  f o r p r e d i c t i o n purposes.  However F i g .  5.6  showed a l a r g e amount of s c a t t e r around the r e g r e s s i o n (SE = 3.3  p a r t due  t ha" ).  to the low  1  The  general,  in  N requirement of sweet corn r e l a t i v e t o  s i l a g e corn f o r example, and considered  weakness of the r e l a t i o n s h i p was  i n p a r t because the r e l a t i o n s h i p  j u s t the sweet corn cobs and  not the whole p l a n t .  In  N tends t o i n c r e a s e y i e l d s of v e g e t a t i v e p l a n t p a r t s  r a t h e r than r e p r o d u c t i v e p a r t s , which i n the case of sweet corn, are the p a r t s which are harvested.  Thus, the  c o r r e l a t i o n s between crop y i e l d s and (before e x c l u d i n g marine s i t e s ) , y i e l d s r a t h e r than f o r cob The  yields  strongest  s o i l N 0 N i n the p r o j e c t -  3  were f o r s t a l k and (Sec.4.3.5).  ' l i n e a r r e l a t i o n s h i p ' approach to e s t i m a t i n g  requirements i s probably production  more r e l e v a n t f o r s i l a g e  than f o r sweet corn.  whole p l a n t i s harvested,  and  whole p l a n t  fertilizer  corn  When u s i n g s i l a g e corn,  furthermore,  the  the N demand of  s i l a g e corn i s c o n s i d e r a b l y higher than t h a t of sweet corn.  ESTIMATING FERTILIZER REQUIREMENTS USING THE RELATIONSHIP BETWEEN SOIL NITRATE AND The  p r e v i o u s two  LOGARITHMIC  CROP RESPONSE  approaches to e s t i m a t i n g N  fertilizer  requirements were s p e c i f i c t o the sweet corn i n the study  area.  From the s t r o n g l o g a r i t h m i c r e l a t i o n s h i p s between s o i l N0 -N 3  and  s t a l k f r e s h y i e l d s and  whole p l a n t  Sec-4.3.5), i t i s p o s s i b l e  f r e s h y i e l d s (Table 4.10a,  to d e r i v e  recommendation system which may  be  r e s u l t s showed t h a t f o r s t a l k and  a more g e n e r a l  applied  whole p l a n t  s t r o n g e s t r e l a t i o n s h i p s were c o n s i d e r i n g depth i n c o n t r a s t Figs.  5.7  (0-20cm), and respectively.  i n t o two Nelson,  show the  The  fresh yields.  fresh  correlations  Dahnke et al.(1977) and  yields  lend  (Cate  they a p p l i e d  this  3  used t o i l l u s t r a t e how  relative  Although, i n the study here relative yield  (fresh)  and  weak, (Fig.5.9, r=0.63(L>»*) i t can the Cate-Nelson procedure s p l i t s  p o p u l a t i o n s , one  response t o added f e r t i l i z e r  and  one  with a low -  1  be  the  with a high p r o b a b i l i t y  c r i t i c a l l e v e l i s found at 26 kg ha  of  probability.  N0 -N i n the 0-50cm 3  depth, somewhat lower than the v a l u e of 39 kg ha" 0-30cm depth d e r i v e d  and  graphical  3  of whole p l a n t s .  dat  fertilizer  r e l a t i o n s h i p between s o i l N0 -N and  s o i l N0 -N (0-50cm) was  graph i n t o two  3  Magdoff et al.(1984)  Cate-Nelson procedure f o r d e v e l o p i n g N  ( f r e s h wt.)  N0 -  Cate-Nelson approach which p a r t i t i o n s the  the r e l a t i o n s h i p between whole p l a n t  The  3  whole p l a n t  strong logarithmic  recommendations i n E a s t e r n USA;  yield  N0 -N i n the 0-20cm  p o p u l a t i o n s s e p a r a t e d by a c r i t i c a l l e v e l  technique t o the  the  r e l a t i o n s h i p s between s o i l  s t a l k f r e s h y i e l d s and  1971).  used the  5.8  The  fresh yields  t o 0-80cm depth f o r the cob  and  themselves t o the  t o other crops.  1  N0 -N i n 3  the  by Magdoff et al.(1984) f o r s i l a g e corn i n  Vermont. The  amount of N r e q u i r e d  d e f i c i e n t p l o t s could  to i n c r e a s e  be d e r i v e d  crop y i e l d on  N  from the e q u a t i o n of the  line  STALK YIELD, FRESH (thd')  40-  20-  20  40  SOIL NO-N kg ha"' (0"20cm) AT SIDEDRESS F i g u r e 5.7 R e l a t i o n s h i p between s t a l k y i e l d , soil nitrate  f r e s h and  (0-20cm) a t s i d e d r e s s showing  p o p u l a t i o n s s p l i t u s i n g the Cate-Nelson method.  WHOLE PLANT YIELD, FRESH (tha ) 1  1  1  1  40 SOIL NOjN kg ha" (0~20cm) AT SIDEDRESS Figure  5.8  Relationship and  soil  between whole p l a n t  nitrate  populations  split  (0-20cm) using  yield,  at sidedress  the Cate-Nelson  fresh showing method  RELATIVE YIELD, FRESH (%) I20-,  • • •  604  40 -\  50 SOIL NOgN kg ha" (0~50cm) AT SIDEDRESS  F i g u r e 5.9 R e l a t i o n s h i p between r e l a t i v e y i e l d , and s o i l n i t r a t e populations s p l i t  100  fresh  (0-50cm) a t s i d e d r e s s showing u s i n g t h e Cate-Nelson method.  110 i n t h e ' r e s p o n s i v e ' quadrant.  F i g . 5.9 shows o n l y seven p o i n t s  i n t h i s quadrant, t o o few f o r p r e d i c t i o n purposes. al.  (1984) however, demonstrated how f e r t i l i z e r  c o u l d be made by s p l i t t i n g t h e i r  Magdoff e t  recommendations  ' r e l a t i v e y i e l d versus s o i l  N 0 N graph' ( c o n t a i n i n g 55 p o i n t s ) i n t o two l i n e s s e p a r a t e d by -  3  the  critical  level:  1) Where N0 -N <0-30cm) < 39 kg ha"  1  3  y = 3. 2 + 0. 185x High p r o b a b i l i t y o f response t o f e r t i l i z e r . 2) Where N0 -N (0-30cm) > 39 kg ha"  1  3  y = 9.57 + 0.023x Low  p r o b a b i l i t y o f response t o f e r t i l i z e r .  Using t h e s l o p e o f e q u a t i o n (1) t h e amount o f N0 -N needed t o 3  i n c r e a s e t h e y i e l d o f N d e f i c i e n t p l o t s was e s t i m a t e d at 5. 4 kg N0 -N per tonne o f y i e l d 3  increase.  The e f f i c i e n c y o f f e r t i l i z e r  uptake was taken as 707. and hence f e r t i l i z e r were made.  Magdoff  recommendations  e t al.(1984) found t h i s method made a c c u r a t e  p r e d i c t i o n s f o r t h e r e s p o n s i v e s i t e s but not f o r the nonresponsive s i t e s . fertilizer  N e v e r t h e l e s s , t h e r e s e a r c h e r s showed  recommendations t o be s u b s t a n t i a l l y improved over t h e  p r e v i o u s system which d i d not i n c o r p o r a t e a s o i l  test.  I f t h e Cate-Nelson procedure i s a l s o a p p l i e d t o t h e graphs i n F i g s . 5.7 and 5.8 i t can be seen t h a t the c r i t i c a l l e v e l can a c t u a l l y be drawn anywhere between two p o i n t s , eg. between 18 and 23 kg h a  - 1  f o r the whole p l a n t f r e s h y i e l d  (Fig.5.8).  Thus  a more c o r r e c t s e p a r a t i o n o f the Responsive and Unresponsive p o p u l a t i o n s would be t o use a c r i t i c a l  'Range' o f 18 - 23 kg  Ill  ha" . 1  T h i s range c o u l d be termed  a region of 'Possible  Response' t o f e r t i l i z e r . Table 5.2 shows the c r i t i c a l ranges o f s o i l N0 -N f o r crop 3  response curves which c o u l d be s p l i t approach.  u s i n g the Cate-Nelson  From t h i s t a b l e i t can be seen how t h e c r i t i c a l  ranges change with depth and with d i f f e r e n t crop parameters, i e . s t a l k s and whole p l a n t s . used t o s p l i t  The Cate-Nelson approach c o u l d thus be  s o i l s with s p e c i f i c l e v e l s o f N0 -N a t s i d e d r e s s 3  into three l e v e l s : L e v e l 1 - Crop response probable. L e v e l 2 - Crop response p o s s i b l e L e v e l 3 - Crop response These L e v e l s w i l l  (Critical  Range).  unlikely.  be s p e c i f i c t o d i f f e r e n t crops as they  were shown t o be f o r t h e d i f f e r e n t p l a n t p a r t s , d i f f e r a c c o r d i n g t o the depth o f sampling.  they w i l l  also  For example, f o r  whole corn p l a n t s : L e v e l 1 = < 18 (0-20cm), < 15 (0-50cm) kg ha"  1  N0 -N. 3  L e v e l 2 = 18-23 (0-20cm), 15-23 <0-50cm) kg ha" L e v e l 3 = > 23 (0-20cm and 0-50cm) kg ha"  1  1  N0 -N.  N0 -N. 3  F u r t h e r r e s e a r c h would be necessary t o develop t h i s for to  crops i n the Fraser Valley,  s o i l N i s l o g a r i t h m i c t h e approach  soil 18-23  approach  however where t h e crop response would a l l o w t h e farmer t o  d e c i d e whether or not he wishes t o add f e r t i l i z e r his  3  according to  N0 -N l e v e l a t s i d e d r e s s . 3  kg ha"  1  N0 -N 3  (0-20cm) may seem low f o r t h e c r i t i c a l  range d i v i d i n g whole p l a n t f r e s h y i e l d s i n t o 'Unresponsive' p o p u l a t i o n s .  'Responsive' and  However i t must be remembered that  Table 5.2 N F e r t i l i z e r Recomnendations: C r i t i c a l Ranges of NOj-N d i v i d i n g Responsive and Unresponsive s i t e s vising the Cate-Nelson method.  C r i t i c a l Range o f NOj-N (kg h a ) - 1  Crop Parameter  S o i l Depth (cm) 0-20  0-50  0-80  Fresh Y i e l d t ha"' Stalks  9-11  12 - 15  19 - 27  Whole Plant  18 - 23  15-23  Whole plant (Fresh)  16 - 22  26 - 27  28 - 29  Whole Plant  18 - 22  28 - 30  33 - 40  Relative Y i e l d  (Dry)  47 kg h a " N was a p p l i e d a t p l a n t i n g and a l s o t h a t t h e dry 1  summers may have l i m i t e d growth and subsequent N requirements. Nevertheless,  t h e c r i t i c a l range o f 18-23 kg h a " does suggest 1  t h a t t h e whole p l a n t requirement f o r N c o u l d have been met s o l e l y by s o i l and s t a r t e r N on many o f t h e s i t e s i n D e l t a , and t h a t o f t e n added s i d e d r e s s  fertilizer  was not necessary.  p o s s i b l e t h a t i n t h e r e g i o n o f study an improvement c o n d i t i o n s may prevent more wasted N f e r t i l i z e r recommendations, allow  unless  F o r example,  than improved N  the negative  o f crop response with s o i l NH*-N, i m p l i e d  t h e c o n d i t i o n s which c r e a t e d  rectified,  in soil  u n l e s s t h a t i s , t h e recommendations were t o  f o r poor s o i l c o n d i t i o n s .  correlation  It i;  added f e r t i l i z e r  that  the high NH*-N l e v e l s a r e  w i l l be o f l i t t l e  value.  114 6. CONCLUSIONS  C o n c l u s i o n s can best be drawn from the p r o j e c t by r e f e r r i n g to  t h e o r i g i n a l q u e s t i o n s posed: 1>  Are s o i l N0 -N or s o i l NH -N s u f f i c i e n t l y c o r r e l a t e d 3  crop response  with  4  t o make a s o i l t e s t  worthwhile?  I t was not w i t h i n t h e scope o f t h i s p r o j e c t t o determine the worth o f a m i n e r a l N s o i l  t e s t f o r a l l LFV a r a b l e c o n d i t i o n s .  However, t h e r e s u l t s seem t o i n d i c a t e t h a t i n a s m a l l a g r i c u l t u r a l r e g i o n such as D e l t a , where n e i t h e r c r o p p i n g systems nor s o i l types vary a p p r e c i a b l y , and where manure use i s limited,  s o i l N0 -N does appear t o be s u f f i c i e n t l y 3  correlated  with t o t a l s o i l p l u s crop N at harvest, t o make i n v e s t i g a t i n g the wider use o f a s o i l The  test  worthwhile.  p r o j e c t showed t h a t s o i l s i n t h e D e l t a area supply a  l a r g e p r o p o r t i o n o f t h e N r e q u i r e d f o r sweet corn growth.  Thus,  when generous amounts o f s t a r t e r N a r e used eg. 47 kg h a " , 1  of  much  the a d d i t i o n a l s i d e d r e s s N i s unnecessary. 2)  I f a s o i l t e s t can be used, t o what depth and on what  date i s i t necessary The  t o sample?  depth o f sampling  resources. sampling  will  depend on f i n a n c i a l and human  F o r sweet corn, t h e r e s u l t s o f the study imply t h a t  down t o 80 cm p r o v i d e s t h e best c o r r e l a t i o n between  s o i l N0 -N a t s i d e d r e s s and cob y i e l d . 3  not be necessary  For other crops i t may  t o sample so deep, i n f a c t ,  s t a l k and whole  p l a n t y i e l d s o f sweet corn i n t h i s study were best with s o i l N0 -N t o a depth o f 20 cm. 3  correlated  115 The time.  best time t o sample i s as c l o s e as p o s s i b l e t o s i d e d r e s s F o r corn, t h i s i s when t h e crop i s almost  30 cm high, f o r  o t h e r crops i t i s the p o i n t j u s t p r i o r t o t h e p e r i o d o f maximum growth and N uptake. 3) Can t h e N s u p p l i e d by t h e s o i l be i n d i r e c t l y estimated by s o i l c h a r a c t e r i s t i c s such as o r g a n i c matter, soil  p r e v i o u s cropping,  texture? The  p r o j e c t showed t h a t t h e range o f s o i l types and cropping  regimes i n D e l t a M u n i c i p a l i t y was too narrow t o have a d i r e c t i n f l u e n c e on N s u p p l i e d by t h e s o i l . be r e l a t e d t o o r g a n i c matter, h i s t o r y i s necessary  however a knowledge o f s i t e  b e f o r e assuming a p o s i t i v e  I f t h e o r g a n i c matter percentage unfavourable  N s u p p l i e d by the s o i l may  relationship.  i s high due t o c o n d i t i o n s  f o r m i n e r a l i z a t i o n , t h e r e may i n f a c t be a n e g a t i v e  c o r r e l a t i o n between o r g a n i c matter and t h e p r o p o r t i o n o f i t which i s converted  t o N0 -N. 3  S o i l pH was shown t o be  s i g n i f i c a n t l y p o s i t i v e l y c o r r e l a t e d with s o i l N0 -N, although pH 3  cannot be used as an e s t i m a t e o f N s u p p l i e d by t h e s o i l be taken  i t can  i n t o c o n s i d e r a t i o n when s o i l N supply i s determined.  N s u p p l i e d by the s o i l may p o s s i b l y be estimated from characteristics,  however f u r t h e r experimentation  i n areas  soil with  widely v a r y i n g s o i l t e x t u r e s and c r o p p i n g regimes i s necessary b e f o r e any such e s t i m a t e s can be e s t a b l i s h e d . 4) Which f a c t o r s have t h e g r e a t e s t i n f l u e n c e on corn uptake of  s o i l and f e r t i l i z e r N? In the D e l t a area, t h e t h r e e s i t e f a c t o r s which had the  g r e a t e s t e f f e c t on crop uptake o f s o i l N0 -N were, poor 3  lis drainage, high l e v e l s o f s a l t s a s s o c i a t e d with marine conditions,  and low pH.  nitrification  These adverse s o i l c o n d i t i o n s i n h i b i t e d  and a v a i l a b i l i t y o f s o i l N t o t h e crop.  5) Does the method o f f e r t i l i z e r  application,  i e . broadcast  p r e p l a n t or s i d e d r e s s e d make a s i g n i f i c a n t d i f f e r e n c e t o the crop use o f f e r t i l i z e r N? T h i s q u e s t i o n cannot study.  be answered from the r e s u l t s o f the  No s i g n i f i c a n t d i f f e r e n c e was found between y i e l d s o f  crops r e c e i v i n g urea N broadcast p r e p l a n t or s i d e d r e s s e d .  No  comment can be made on t h e e f f i c i e n c y o f t h e d i f f e r e n t methods of  fertilizer  fertilizer two  a p p l i c a t i o n because t h e l a c k o f response t o  may have been due t o any number o f f a c t o r s ,  eg.  the  u n u s u a l l y hot, dry summers d u r i n g which the p r o j e c t was  c a r r i e d out, t h e s u f f i c i e n t amounts o f s o i l N p l u s s t a r t e r N f o r crop requirements  before a d d i t i o n a l f e r t i l i z a t i o n ,  the i n e f f i c i e n c y o f both methods o f f e r t i l i z e r  and p o s s i b l y  applications.  REFERENCES A d d i s c o t t , T. M. (1977). A simple computer model f o r l e a c h i n g i n structured s o i l s . J o u r n a l o f S o i l S c i . 28:554-563. A d d i s c o t t , T.M. (1982). Computer assessment of the N s t a t u s d u r i n g winter and e a r l y s p r i n g of s o i l s growing winter wheat. In Batey, T. , Vlassak, K. , and V e r s t r a e t e n , L.M.J., (ed.) 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S i m u l a t i e van de s t i k s t o f v e r e l i n g i n de grond i n w i n t e r en v o o r j a a r . Haren: Inst. Bodemvruchtrbaarheid. Rapp 4-81.  Appendix 1  D a i l y P r e c i p i t a t i o n (mm) A p r . - S e p t . Vancouver I n t e r n a t i o n a l A i r p o r t .  1984/1985.  D a i l y P r e c i p i t a t i o n (mm) Date Apr 1 2 3 4  5.0  22.2 3.7 2.4  5  1.4  TR 6.4  6 7 8  0.6 7.4 0.4  TR 6.0  TR TR  9 10 11 12 13 14 15  21.9 3.8 9.1  2.6 1.2 9.9 0.8 5.3 0.6  0.4  16 17 18 19 20 21 22 23 24 25 26  8.7  May  1984 Jun  16.6 5.3 TR 1.4 0.6 1.8 5.6 7.2  TR 36.1  Aug  0.3 0.4 3.0 14.6 TR TR 12.2 0.2 0.5 7.4 9.4  PP 2.0  Sep  Apr  May  4.2 13.0 0.4  5.5  TR  5.2 1.4 0.6 TR  3.0 TR 0.2  TR  7.4  24.0 1.4  2.6  TR  TR  0.6 TR 1.7 TR 0.3 TR  TR PP 3  SD TR TR 2.2  TR TR TR 2.0 TR TR  TR 4.0 7.8 0.4  0.2 2.7  TR  TR HARV  0.4 1.2  2.0 TR  1.6  3.2 TR  11.8 8.2 TR TR 22.2  TR  1985 Jul  TR 4.7 4.8  7.2 0.2 4.0 3.2  TR  TR 2.4 TR 6.0  2.8  4.8 19.8 15.4 TR  0.6  SD=Sidedress  1.4  12.4  TR  24.2  10.8 1.1 4.4  1.0 1.2  TR 1.0 2.2 5.0  1.2 TR TR TR 7.4 2.6  1.3 TR TR  TR 2.8 0.4 HARV  14.6 1.2 17.6 2.8  HARV=Harvest  TR TR  6.0  2.0 1.2  SD TR  Sep  0.2 12.0  TR 0.4  Aug  2.2  2.9 PP=Planting  Jun  3.9  TR  27 28 29 30 31  Jul  TR=Trace  0.8 TR TR  7.2 0.6  0.6  Appendix 2  S o i l c h a r a c t e r i s t i c s o f Reynelda farm s i t e s .  1984 (Site A) Depth (cm)  Soil Parameter  0-20  20-50  1985 (Site B) Depth (cm)  50-80  0-20  20-50  50-80  % Silt  75.0  76.0  74.0  69.0  73.0  72.0  % Sand  5.0  6.0  13.0  1.0  6.0  4.0  % Clay  20.0  18.0  13.0  30.0  21.0  24.0  1.43  1.46  1.22  1.13  1.28  1.18  % Organic matter  2.4  1.9  1.9  3.8  2.1  2.6  Total N %  0.2  0.2  0.2  0.2  0.1  0.1  pH (H,0)  5.0  4.3  3.8  4.8  4.6  4.3  Salts (E.C.) dS m"'  0.48  0.32  0.48  0.56  0.96  0.72  Nitrates (NO,-N) mL Phosphorus (P)  13.0  5.0  3.0  11.0  8.0  11.0  144.0  22.0  7.0  97.0  13.0  21.0  0.36  0.18  0.12  0.43  0.25  0.23  1.32  0.81  0.45  0.76  1.24  0.49  4.69  2.38  0.62  2.4  0.85  0.91  0.00  0.00  0.00  0.20  1.02  0.42  6.37  3.37  1.19  3.79  3.37  2.05  0.00  0.00  0.00  5.40  30.40  20.60  0.00  0.00  0.00  0.16  1.00  0.50  18.1  24.3  58.5  61.0  177.0  131.0  0.59  0.32  0.23  1.24  0.81  0.84  6.8  8.7  7.3  7.9  4.7  5.6  160.2  241.7  333.2  312.2  358.1  329.2  17.0  4.8  2.1  17.5  2.7  5.5  1.5  1.1  1.1  1.4  0.5  0.7  Bulk density a t (g 1 B L " )  sidedress  1  Mg  mL"' Potassium (K) me lOOmL Magnesium (Mg)  jtg  -1  me lOOmL Calcium (Ca) me lOOmL Sodium (Na) me lOOmL -  -1  T o t a l Cations me lOOmL Exchangeable -1  sodium % Sodium adsorption r a t i o Sulphate (SO^-S) mL Boron (B) vg mL ' Copper (Cu) -1  jig  -  mL Iron (Fe)  Mg  Mg  mL ' -  Manganese (Mn) mL ' Zinc (Zn) *tg mL -  1  30 m  6m SCALE: lcm = 2m  7K  4m  I00PP  TREATMENT:  0  50  50  IOOPP  IOOSD  IOOPP  200  IOOSD  50  100  200  IOOSD  IOOPP  100  IOOSD  100  100  200  200  100  IOOPP  0  0  0  50  200  IOOSD  0,50,100,200 (kghcf'N) 24m 50  SD = sidedress PP = preplant  BLOCK  0  I  Appendix  IE  3.  Field  p l a n example:  response  trial.  Site  Replicated A.  fertilizer  129  N i t r o g e n F e r t i l i z e r T r i a l on Sweet Corn F o r y o u r 1985 f i e l d ( s ) o f sweet c o r n c o n t a i n i n g t h e " s i d e - d r e s s / n o side-dress" field trial strips. ( P l e a s e complete  t h e q u e s t i o n s below a s f a r a s p o s s i b l e . )  1981  YEAR  1982  1983  1984  What c r o p ? Cover c r o p ? What s o r t ?  y o r  x  Manure? / o r X Type a n d approximate rate? Lime? / o r X When? How much? How ( i f a t a l l ) i s t h i s f i e l d d r a i n e d a n d i r r i g a t e d ?  What were t h e r a t e s o f s t a r t e r a n d s i d e - d r e s s n i t r o g e n a p p l i e d t o t h e sweet corn?  On what d a t e was t h e c o r n  planted?  Appendix 4. M u l t i f a r m  trial:  Questionnaire  farmers t o o b t a i n s i t e  sent  information.  to  Appendix 5  Methods used f o r s o i l analysis by B.C. Feed and t i s s u e t e s t i n g laboratory, Kelowna.  Method o f analysis  Reference  % S i l t , Sand, Clay  P a r t i c l e s i z e analysis  Day 1965  % Organic matter  Loss on i g n i t i o n  Nelson and Somtners 1982  Total N %  Kjeldahl N  Brenner and Mulvaney 1982  pH (H 0)  1:2  Salts (E.C.)  Conductivity  NOj-N  Kelowna extract Cadmium reduction + Autoanalyser  van Lierop 1986 Technicon Autoanalyser 1977  P K Mg Ca Na SCy-S  Kelowna extract  van Lierop 1986  Soil Parameter  t  soil:water r a t i o Electrode  ICPAES T o t a l Cations  Sum of cations.  B  Hot water extract ICPAES DTPA extract ICPAES  Cu Fe Mn Zn  Black 1965 Page 1982  Appendix 6  Multifarm t r i a l : Previous crops, mineralization, crop + s o i l N (0-80cm), and f e r t i l i z e r e f f i c i e n c y estimates.  Year  Previous crop  Site  Mineralization kg ha"  1 2  Corn  104.1  Beans  1  3  Beans  195.7 89.4  1  4  1 1 1  5 6 7 8  Peas Potatoes  1 1  9 10  1 1 1 1 1 1  11 12 13 14 15 16 17 1 2 3  1 1  1  1 2 2 2 2 2 2 2 2 2 2 2  T o t a l crop + s o i l N kg ha"'  Fertilizer efficiency %  116.8 203.4  52 7  98.3  -9  88.3 42.3  94.3 46.9  18 27  Peas Spring barley Potatoes  122.1 81.3 190.3  137.5 96.5 209.2  10 -2  Spring barley  172.2  189.3  -26 -4  Potatoes Beans Potatoes Peas Potatoes  100.2  110.6 102.4 145.6 112.6  19 37 9 20  65.0 169.4 123.2 168.3 349.1 218.5 321.7  22 6 34 10  ? Peas Peas Potatoes Peas Peas  4 5  Peas  6 7 8 9 10 11  Peas  ? ? Corn Potatoes Strawberries Peas  95.3 138.0 101.3 59.0 154.3 115.1 148.7 305.1 192.0 302.3 190.5 155.0 251.9 118.6 184.2 168.2 144.2 103.8  215.3 184.7 264.7 130.4 212.9 217.4 167.2 120.4  42 4 0 25 2 13 38 10 26 13 7  Mineralization = Crop N + S o i l Mineral N (0-50cm) - s t a r t e r x 0.7 T o t a l crop + s o i l N = " (0-80cm) F e r t i l i z e r e f f i c i e n c y = N uptake f e r t i l i z e d p l o t - N uptake control p l o t Amount of f e r t i l i z e r N sidedressed = 135 kg ha'  NOjNlkghd') YR SITE 0-20 20-50 50-80 1 1 1 1 1 1  1 1  1  1  2 3 4 5 6 7  8 9  1 10  1 11 1 12 1 13  1 14 1 15 1 16 1 17  2 1 2 2 3 2 4 2 5 2 6 2 7 2 2 8 2 9 2 10 2 11  13 55 7 36 46 b2 8 65 5 77 29 49 4 17 ?9 27 n 30 3 20 1 1 33 22 89 18 18 10 77 5 15 4 80 38 67 46 47 43 59 70 23 4 t 51 27 0 0 16 39 12 6 0 30 87 30 06 37 .91 25 .42  23 3 17 6 7 21  36 .87 89 99 54 61 ? ?1 16 10 2 1 33 87 8 33 16 57 25. 8 0 5 03 25 25 2 55 36 12 47 91 24 .95 28 27 26 54 26 29 •1? 7 1 1 1 84 19 . 7 3 48 . 6 3 49 . 5 3 30 .5.1  20 . 0 0 .95 7 .06 5 82 .51 17 39 26 2 25 10 94 24 2 . 10 6 38 16 69 3 21 27 ..53 7 .54 22 61 47 .21 19 .28 38 . 73 32 52 19 93 35 92 1 35 27 54 48. , 23 36 20 19 93  0~50 36 .91 1 1. 23 64 . 7 0 15 .64 7 81 51 . 10 6 .68 45 .37 52 . 1 1 4 .07 19 66 39 .46 43 .98 15 . 8 0 30 .4 1 7 .35 74 . 79 94 . 3 9 68 .54 98 .51 68 .05 53 . 29 59 . 10 24 .44 50 .60 78 . 6 9 87 .44 55 .93  NH^N(kghd') 0"80 56 .91 12 . 18 71 .77 2 1 .46 8 .32 68 . 49 6 94 47 .62 63 .06 4 32 2 t . 76 45 .84 6 0 .67 19 .02 57 .94 14 . 9 0 97 . 3 9 14 1 . 5 9 87 .82 137 .24 100 .57 73 .22 95 .02 25 . 8 0 78 . 15 126 .92 123 .65 75. .87  0"20 20-50 50-80 9. 1 14 10.  16 .84 . 78 38 IO. 54 3. 77 8 59 6 . 57 7 .5 1 2 5 . 92 67 2 86 7 . 79 3. 8 0 16 75 5 . 10 3 .33 7 . 15 6 .23 B .78 8 . 12 7.. 5 0 5 . 46 22 .84 8.. 12 7 . 12 6 .24 2 .42  16. .82 7. 74 76 4 . 30 5 07 8 .54 .55 5 19 9 54 4 37 56 5 18 10 66 4 .02 4 .64 , 5 . 47 5..76 7 .62 3 .88 2 .92 2 . 17 2 .29 3 .88 2 .49 3 .29 3 . 19 7 .79 4 .72  2 9 12 1 4 8  .00 51 46 . 79 1 1 . 12 .52 8 .45 5 .02 4 .87 1 .57 1 .59 8 .81 2 . 29 7 .7 1 14 .08 5 .49 .92 3 .06 2 .45 1 1. 8 3 10 . 6 3 1 1.05 1 1.75 8 .96 7 .57 8 .05 23 . 8 6  0-50 2 5 . 97 9 . 58 15. 55 14 . 68 15 . 61 12. 32 9 14 1 1, .76 17 . 05 30. . 29 1 22 8 ..04 18. 45 7 . 83 21 ,39 . 10. 57 9. . 0 9 14 , 77 10, . 1 1 11 . 7 0 10 . 29 9 .79 9. . 35 25 . 3 3 11 .41 10 .31 14 .04 7 . 14  0"80 cm 2 7 . 97 19 0 9 28. 01 16 . 48 19 73 20 43 9. 66 20. 21 22 . 07 35. 16 2 . 79 9 63 27. 26 10. 12 29. . 10 24. 65 14 .58 15 .69 13 . 17 14 . 15 22 . 1 1 20 .42 20 . 4 0 37 .08 2 0 .37 17 . 8 7 22 .08 31 .OO  Appendix 7. Multifarm T r i a l : S o i l n i t r a t e and ammonium (kg ha ) a t s i d e d r e s s . 1  (J  133  AB C D E 1 1 i 1 1 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2  I)  i 1 1 2 2 2 3 3 3 4 4 4 5 5 5 1 1 1 2 2 2 3 3 3 4 4 4 5 5 5  1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3  F .80 .80 .50 .60 .60 .60 .70 .60 .40 .70 .50 .50 .60 .70 .50 .70 1 .30 .50 .70 .50 .60 .90 .80 .70 .80 .60 .50 .60 .50 .50  G  80 1 70 1 70 50 1 50 1 80 1 40 1 70 i 40 80 1 50 1 90 90 2 20 1 90 .80 2 .20 1 .70 .70 1 .70 1 .60 .70 1 .50 1 .90 1 .00 1 .80 2 .00 .90 1 .50 1 .60  1  H 80 74 70 78 61 79 77 71 67 79 73 67 76 69 64 79 75 69 79 71 67 78 75 65 77 71 67 78 0 73 0 70  0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0  o  5 0 5 0 6 1 5 0 5 0 6 1 5 0 5 0 6 1 5 0 5 0 6 1 5 0 5 0 6 1 5 0 5 0 6 .1 5 .0 5 .0 6. 1 5 .0 5 .0 6 .1 5 .0 5 .0 6. 1 5 .0 5 .0 6. 1  J  1 . 24 1 .40 1 .08 1 .24 1 .40 1 .08 1 .24 1 .40 1 .08 1 . 24 1 .40 1 .08 1 .24 1 .40 1 .08 1 .24 1 .40 1 .08 1 .24 1 .40 1 .08 1 .24 1 .40 1 .08 1 .24 1 .40 1 .08 1 .24 1 .40 1 .08  A = Year 1 = 1984 2 = 1985 B = Date o f sampling C = Treatment 1 = preplant 2 = sidedress D = B l o c k (1-5) E = Depth 1 = 0-20cm 2 = 20-50cm 3 = 50-80cm F = NH.-N -1 . ^ .. g g moist s o i l 4  G = N0 -N g g 3  1  moist  soil  H = Dry weight o f s o i l as p r o p o r t i o n o f moist weight  2)  1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1  2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2  1 2 1 2  1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 2 2 2  1 1 1 2 2 2 3 3 3 4 4 4 5 5 5 1 1 1 2 2 2 3 3 3 4 4 4 5  1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1  2 5 2 2 5 3  1 .30 1 30 .60 1 20 1 .30 1 OO 80 1 00 80 1 30 90 60 1 10 1 10 1 20 1 10 1 10 70 60 2 10 1 00 1 00 90 90 1 60 1 10 80 80 .70 .50  3 2 2 3 2 2 3 3 2 3 2 2 4 4 3 3 2 2 3 3 5 3 3 3 3 3 3 3 3 3  00 50 OO 20 70 50 20 10 60 20 90 90 60 20 70 30 50 20 10 10 20 OO OO 50 50 50 50 10 40 20  0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0  78 74 68 76 72 68 77 72 68 78 75 68 75 71 66 78 75 69 76 73 67 78 76 72 77 72 68 76 71 68  9 7 7 9 7 7 9 7 7 9 7 7 9 7 7 9 7 7 9 7 7 9 7 7 9 7 7 9 7 7  4 2 2 4 2 2 4 2 2 4 2 2 4 2 2 4 2 2 4 2 2 4 2 2 4 2 2 4 2 2  1 33 1 30 1 14 1 .33 1 30 1 14 1 33 1 30 1 14 1 33 1 30 1 14 1 33 1 30 1 14 1 33 1 30 1 14 1 33 1 30 1 14 1 33 1 30 1 14 1 33 1 30 1 14 1 33 1 30 1 14  I = Temperature °C 3 J = Bulk d e n s i t y g cm  Appendix 8a. N i t r o g e n m o n i t o r i n g study: 1) 25 A p r i l  1984  2) 9 May 1984.  134  AB C D E 1 3  2)  i 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2  1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1  3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3  1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1  4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4  2 2 2 2 2 2 2 2 2 2 2  1 1 1 1  4 4 4 4  2 2 2 2  4 4  1 1 1 1 1 1 1 1 1 1 1 1 1 1 1  F  G  1 1  1 .20  1 1 2 2 2 3 3 3 4 4 4 5 5 5 1 1 1 2 2 2 3 3 3 4 4 4 5 5 5  2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3  .60 .50 1 . 10 .90 .80 .90 .70 .60 .70 .70 .70 1 . 10 .70 .60 1 .20 1 .OO .70 .90 .70 .80 1 .20 .70 .50 2 . 10 .80 .70 .80 .70 .60  4.00 2.50 2.00 4.00 3.00 2.50 3.50 3.00 2.50 4.00 3.00 3.00 5.00 5.00 4.50 4.00 3 .OO 2.50 3.50 3.00 3.00 3.00 3.00 2.50 4.00 4 .00 3.50 4.00 4.00 3.00  1 1 1 2 1 3  15.00 .80 1 . 10 10.00 1 .20 1.10 20.00 1 .80 1 .50 16.50 1 .60 .90 11.00 1 .30 .90 1 .60 .80 .60 .80 .50 .60 1 .00 .60 .70 1 .OO 1 .OO  7.00 3.50 2.50 6.00 3.00 2.50 8.00 3.50 2.50 7.00 3.00 3.00 8.00 4.00 3.00 5.00 2.50 2.00 5.50 3.50 2.50 5.00 3.50 3.00 5.50 5.50  0.79 0.76 0.68 0.80 0.75 0.68 0.79 0.73 0.69 0.80 0.75 0.68 0.78 0.70 0.66 0.80 0.74 0.70 0.79 0.73 0.68 0.80 0.74 0.72 0.79 0.73  11.1 10.0 9.4 11.1 10.0 9.4 11.1 10.0 9.4 11.1 10.0 9.4 11.1 10.0 9.4 11.1 10.0 9.4 11.1 10.0 9.4 11.1 10.0 9.4 11.1 10.0  1.38 1.44 1.10 1.38 1.44 1 . 10 1 .38 1.44 1.10 1.38 1.44 1.10 1.38 1.44 1.10 1.38 1.44 1.10 1.38 1.44 1 . 10 1.38 1.44 1 . 10 1.38 1.44  .60 .80 .60 1 .OO  3.50 5.00 3.50 3.00  0.67 0.79 0.72 0.66  9.4 11.1 10.0 9.4  1.10 1.38 1.44 1.10  2 2 2 3 3 3  4 4 4 5 5 5  1 1 1 2 2 2 3 3 3  4 4  1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2  4 3 5 1 5 2 5 3  H 0 . 78 0 . 70 O. 67 0 . .79 O .76 0 . .67 0 . .76 0. .71 0 .67 0 .77 0 .75 0 .65 0 . 76 0 .72 0 .66 0 .79 0 .74 0 .69 0 .80 0 .75 0 .67 0 .78 0 . 75 0 .68 0 .77 0 .75 o .67 0 .76 0 .74 0 .66  I 9. 4 7 .2 7 .2 9. 4 7. 2 7. 2 9. 4 7.2 7 ..2 9. 4 7.2 7. 2 9 .4 7 ..2 7.2 9 . .4 7.2 7. .2 9 .4 7. .2 7 .2 9 .4 7 .2 7 .2 9 .4 7 .2 7 .2 9 .4 7 .2 7 .2  J 1 , 22 1 ,44 . 1 .. 10 1 .22 1 44 1 . 10 1 .22 . 1 .44 1 ., 10 1 .22 1 . 44 1 . 10 1 .22 1 .44 1 . 10 1 .22 1 . 44 1 . 10 1 .22 1 .44 1 . 10 1 .22 1 .44 1 . 10 1 .22 1 .44 1 . 10 1 .22 1 .44 1 . 10  Appendix 8b. N i t r o g e n monitoring 1) 23 May  1984  study:  2) 7 June  1984.  135  F  AB C D E 1 5 1 5  5 .00 1 .20 .70 4 .OO 1 .20 1 .00 4 .00 1 .30 1 .00 10 .00 1 . 10 1 .20 3 .00 1 . 10 1 . 10 .90 .60 .60 . 10 .80 .80 .70 .80 .90 .80 .60 .50 .70 .90 .50  11 1 1 1 11 1 1 1 1 1 1 11 1 1 1 1 1 51 1 1 1 5 51 51 1 1 5 51 1 5 51 1 5 1 1 1 1 1 1  5  1 5 5 5 5 2 5 2 5 5 5 2 2 2 2 5 5 52 2 2 5 2 5 52 5 2 5 2 2 5 2 5  1 1  1 1 1 1 1 1  1 1  2 2 2 3 3 3 4  5  1 1  2 3 1 2 3 1  2 3  4 2 4 3  15 2 25 3  11 1 1  2 2 2 2 3 3 3 3 4 4 4 5 5 5  2 3 1 2 3 1 2 3  3  G 24 .40 5 .OO 3 .00 18 .40 4 .00 4 .00 18 .00 5 .00 4 .00 22 .00 5 .00 5 .00 18 .oo 7 .00 6 .00 11 .20 3 .00 2 .00 7 .oo 3 .50 3 .00 10 .40 5 .00 4 .00 8 .00 9 .oo 4 .00 8 .00 4 .00 3 .00  26 .OO 7 .40 5 .50 15 .OO 5 .20 3 .80 16 .40 7 .50 5 .20 16 . IO 5 .20 4 .80 24 .80 8 .60 4 .90 8 .OO 5 .OO 4 .40 8 .40 5 .OO 4 .20 10 .80 5 .90 4 .50  1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1  6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6  1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2  1 1 1 2 2 2 3 3 3 4 4 4 5 5 5 1 1 1 2 2 2 3 3 3  1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3  3 .70 1 .20 1 .60 1 .50 1 .00 1 .00 2 .40 1 .40 1 .20 1 .50 .80 1 .00 2 .90 1 . 00 .80 1 .50 1 .00 1 .50 1 .30 1 . 10 1 .OO 1 . 10 1 . 10 1 . 10  1 1 1 1 1 1  6 6 6 6 6 6  2 2 2 2 2 2  4 4 4 5 5 5  1 2 3 1 2 3  1 .40 11 ..80 1 . 10 6. .00 5. .00 .70 1 .00 12, .OO 6. OO .70 1 .20 5, .00  H 0 .82 0 .75 0 .68 0 .81 0 .75 0 .70 0 .80 0 .71 0. .68 0 .81 0 .77 0 .70 0 .80 0 .71 0 .66 0 .81 0 .75 0 .68 0 .81 0 .72 0 .67 0 .81 0 .74 0 .70 0 .79 0 .74 0 .68 0 .80 0 .75 0 .68  I 13. 9 12 8 12 .2 13. 9 12 . 8 12. .2 13. .9 12. 8 12. .2 13. 9 12. .8 12. 2 13. .9 12. 8 12 .2 13, .9 12 8 12. 2 13. .9 12 8 12 .2 13 .9 12 8 12 .2 13 .9 12 .8 12 .2 13 .9 12 .8 12 .2  J 1 .61 1 .44 1 . 10 1 .61 1 .44 1 . 10 1 .61 1 .44 1 . 10 1 .61 1 .44 1 . 10 1 .61 1 .44 1 . 10 1 .61 1 .44 1 . 10 1 .61 1 .44 1 . 10 1 .61 1 .44 1 . 10 1 .61 1 .44 1 . 10 1 .61 1 .44 1 . 10  0. .80 0. .74 0. .68 0. .80 O..73 0. .68 0. .79 0 .74 0, .67 0 .80 0. 74 0. .67 0. ,79 0. .73 0. .66 0. 81 0. .76 0 . .71 o. .60 0. .73 o. .66 0 .80 0 .74 o. 68  15 12 12 15 12 12 15 12 12 15 12 12 15 12 12 15 12 12 15 12 12 15 12 12  .6 .8 .8 .6 .8 .8 .6 .8 .8 .6 .8 .8 .6 .8 .8 .6 .8 .8 .6 .8 .8 .6 .8 .8  1 .35 1 .44 1 . 10 1 .35 1 .44 1 . 10 1 .35 1 .44 1 . 10 1 .35 1 .44 1 . 10 1 .35 1 .44 1 . 10 1 .35 1 .44 1 . 10 1 .35 1 .44 1 . 10 1 .35 1 .44 1 . 10  80 71 67 80 72 0 . 66  15. 6 12. 8 12. 8 15 . 6 12. 8 12. 8  1 ,35 . 1 .44 1 ,. 10 1 .35 , 1 .44 , 1 ., 10  0. 0. 0. 0. 0.  Appendix 8c. N i t r o g e n m o n i t o r i n g 1) 20 June 1984  study:  2) 4 J u l y  1984  136  2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2  F  c DE  AB 1  1 1  1  1 1  1 1  1 1 1 1 1 1 1 1 1  1 1 1 1 1 1 1 1 1 1 1  1 1 1 1 1 1  1  1 1  2 3 1 2 1 1 2 2 1 2 3 1 3 1 1 3 2 1 3 3 1 4 1 1 4 2 1 4 3 1 5 1 1 5 2 M 5 3 2 1 1 2 1 2 2 1 3 2 2 1 2 2 2 2 2 3 2 3 1 2 3 2 2 3 3 2 4 1 2 4 2 2 4 3 2 5 1 2 5 2 2 5 3  2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2  2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2  1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2  1 1 1 2 2 2 3 3 3 4 4 4 5 5 5 1 1 1 2 2 2 3  1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1  2 2 2 2 2 2 2 2  2 2 2 2 2 2 2 2  2 2 2 2 2 2 2 2  3 3 4 4 4 5 5 5  2 3 1 2 3 1 2 3  7 .50 5 .OO 1 .00 4 .50 1 .00 8 .50 9 .50 8 . 50 2 .00 9 .50 2 .00 10 .00 20 .50 8 .00 1 .50 9 .50 9 .00 .00 3 .00 7 .50 1 .00 8 .50 2 .00 10 .00 4 .50 5 .50 1 .00 7 .50 1 .00 8 .50 5 .00 .50 4 .00 .50 1 .00 5 .00 . 50 6 .50 7 .00 .50 7 .50 .50 8 .00 .50 50 50 1 .50 50 1 .0 0 1 .50 50 50  9. OO 9. 50 7 .50 8 . 00 8 . 50 6 .50 9. 50 9 . 50  I  H  G  4 . .00 .00 4 .00 .00 3 .50 .00 4 .00 .00 8 . .00 .00 .00 10.. 50 4 .. 50 .50 8 .00 .50 8 . .50 .50 3..50 .50 7 . .50 .00 7 . .00 .50 3..50 .50 7 . .50 .50 .00 10..50 3 .00 .00 4 .00 .00 3..50 .00 4 . .00 .50 e..00 .50 6 .00 .00 6 .50 .00 9 .00 .00 9..50 .00 3 .50 .50 6 .00 .00 . 50 8 .00 4 .50 1 .00 8 .00 .50 .50 10 .50  2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 3 2 2 2 3 2  0. 73 0. 66 0. 64 0. 74 0. 67 0. 62 0. 74 0. 68 0 69 0. 71 0. 70 0..71 0, .63 0..66 0. 65 0..69 0..64 0..64 0 . 74 0 .67 0, .63 0 .68 0 67 0..62 0 .75 0 .68 0 .69 0 .75 0 . 70 0 .70  0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0  .73 .66 .62 .75 .67 .62 . 75 .67 .69 .75 .70 .70 .75 .68 .67 .74 .67 .65 . 74 .66 .66 .75  0. 0. 0. 0. 0. 0. 0. 0.  69 63 74 68 70 76 71 72  J  «  12 .. 5  12 . 5  12 .. 5  12 ..5  12 .. 5  12 .5  12 .5  12 .5  12 .5  12 .5  15 .9  15 .9  15 .9  15 .9  15 .9  15 .9  15 .9  15 .9  15 .9  15 . 9  1 .. 14 1 .. 28 1 .. 18 1 ,. 14 1 .28 . 1 .. 18 1 . 14 1 . 28 1 .. 18 1 . 14 1 .28 1 . 18 1 . 14 1 .28 1 .. 18 1 . 14 1 .28 1 . 18 1 . 14 1 .28 1 . 18 1 . 14 1 . 28 1 . 18 1 . 14 1 .28 1 . 18 1 . 14 1 .28 1 . 18  1 .07 1 .28 1 . 18 1 .07 1 .28 1 . 18 1 .07 1 .28 1 . 18 1 .07 1 .28 1 . 18 1 .07 1 .28 1 . 18 1 .07 1 .28 1 . 18 1 .07 1 .28 1 . 18 1 .07 1 1 1 1 1 1 1 1  .28 . .18 .07 . . .28 .18 .07 .28 .. 18  Appendix 8d. N i t r o g e n m o n i t o r i n g 1) 8 May  1985  study:  2) 22 May  1985.  137  AB C D E 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2  2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2  3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3  4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4  1 1 1 1 1 2 1 1 3 1 2 1 1 2 2 1 2 3 1 3 1 1 3 2 1 3 3 1 4 1 1 4 2 1 4 3 1 5 1 1 5 2 1 5 3 2 1 1 2 1 2 2 1 3 2 2 1 2 2 2 2 2 3 2 3 1 2 3 2 2 3 3 2 4 1 2 4 2 2 4 3 2 5 1 2 5 2 2 5 3  1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2  1 1 1 2 2 2 3 3 3 4 4 4 5 5 5 1 1 1 2 2 2 3 3 3 4 4 4 5 5 5  1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3  F  G  H  4 . 50 2 .50 2 .00 2 .50 2 .00 3 .00 9 .00 7 .50 5 .00 4 .00 2 .00 2 .00 8 .50 2 .50 3 .50 . 1 .50 1 .50 . 1 .50 . 2 .00 . 2..00 2 ,00 . 3. .00 1 ,50 . 1 .50 3. 00 1 .50 2 .00 2. 00 2. 00 2 .50  9 . 50 4 .00 3 .50 9 .50 8 .50 6 .00 20 .00 10 .50 7..00 1 1.00 6 .50 7 .00 1 1.00 8 .00 10 .00 7..00 4 .00 . 4 .00 . 10..00 7 .00 . 5..50 15..50 7 .50 , 7..50 10. 00 7 .00 7 .50 10..00 8. 50 10. OO  0 . 72 0 .64 0 .62 0 .73 0 .66 0 .63 0.. 72 0. 68 0.,67 0.,71 0. 68 0., 74 0.,71 0. 65 0. 65 0. 71 0. 65 0. 6G 0. 71 0. 64 0. 65 0. 70 0. 64 0. 62 0. 72 0. 68 0. 69 0. 73 0. 70 0. 72  2 .50 21 .00 7 .00 .50 3,.00 10. 00 .50 10. 50 2 .00 12 .50 1 .50 8 .00 7 .50 25..00 . .50 1 1.00 .50 2 .00 8 . 6 .00 20..00 . 1 .50 1 1.00 , 2 .00 14 ,00 6 .00 25..00 1 .00 10,,50 .50 1 1.00 1 . 50 1 1. 50 .50 5 .00 3 .00 1 .00 .50 18 .50 1 .00 8 .50 1 . 50 8 .OO 1 .00 15 .00 .50 10 .50 1 .00 10 .00 3 .00 15 .00 1 .00 10 .00 1 .00 9 .50 . 50 1 1.50 9 .50 .OO .00 10 .50  0. 75 0. 69 0. 63 0. 74 0. 75 0. 64 0. 77 0. 72 0. 70 0. 76 0. 70 0. 71 0..76 0. 70 0..67 0 . 75 0..74 0..69 0,, 74 o..66 0..65 0..76 0 .69 0..63 0 .74 0..70 0 .71 0 . 77 0 . 70 0 .72  I  J  0 . 98 1 . 28 1 . 18 15 . 8 0 .98 1 . 28 1 . 18 15 .8 0..98 1 .. 28 1 .. 18 15 ,8 0..98 1.. 28 1.. 18 15,.8 0..98 1.. 28 1. 18 15 .8 , 0. 98 1. 28 1. 18 15,.8 0. 98 1. 28 1. 18 15 .8 0. 98 1. 28 1. 18 15..8 0. 98 1. 28 1. 18 15..8 0. 98 1. 28 1. 18 15 .8  18 . .8 18 .8 18. 8 18 .8 . 18 .8 18 .8 18 .8 18 .8 18 .8 18 .8  1 .1 1 1 .28 1 .18 1 ,. 1 1 1 ,. 28 1 ,. 18 1 .. 1 1 1 .28 . 1 .. 18 1 ., 1 1 1 . 28 1 ., 18 1. 1 1 1 .28 1 . 18 1. 1 1 1 .28 1 . 18 1. 1 1 1 . 28 1 . 18 1. 1 1 1 .28 1 . 18 1. 1 1 1 .28 1 . 18 1. 1 1 1 . 28 1 . 18  Appendix 8e. N i t r o g e n m o n i t o r i n g 1) 5 June 1985  study:  2) 19 June  1985.  138  AB 1)  o\  2)  2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2  5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5  c DE  H  F  G  1 1 1 1 1 2 1 1 3 1 2 1 1 2 2 1 2 3 1 3 1 1 3 2 1 3 3 1 4 1 1 4 2 1 4 3 1 5 1 1 5 2 1 5 3 2 1 1 2 1 2 2 1 3 2 2 1 2 2 2 2 2 3 2 3 1 2 3 2 2 3 3 2 4 1 2 4 2 2 4 3 2 5 1 2 5 2 2 5 3  .50 . 50 .oo 2 .00 .50 6.00 .50 .OO 2.50 1 .50 .50 1 . 50 3.50 1 .00 1 .50 .00 .00 .50 2.50 .00 .OO .50 .OO .50 .00 .50 .50 .00 .00 .00  14 50 5 50 3 50 23 50 1 1 00 2 50 16 50 9 50 6 50 17 50 9 OO 10 50 20 50 1 1 50 10 OO 12 00 7 00 5 00 14 00 7 00 5 00 16 50 10 50 9 00 12 00 8 50 9 50 13 50 10 50 8 OO  0 o 0 0 0 0 0 o 0 0 0 0 0 0 o 0 0 0 0 0 o 0 0 0 0 0 0 0 o 0  76 73 62 76 69 63 77 70 69 76 69 72 76 68 67 75 66 62 75 70 69 76 68 65 77 69 71 76 71 71  J 18 5 18 5 18 5 18 5 18 5 18 5 18 5 18 5 18 5 18 5  6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6  1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 2 2  1 1 1 2 2 2 3 3 3 4 4 4 5 5 5 1 1 1  1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3  1 .OO .50 3 .00 1 .50 .50 2 .00 1 .50 1 .OO .50 2 .00 .50 .50 .50 1 .50 .50 1 .00 1 .50 .50  16 5 4 20 9 7 17 9 5 19 9 10 18 13 10 10 5 4  50 50 50 OO 00 50 00 50 00 OO 50 50 OO 50 OO 50 50 00  O 0 0 0 0 0 0 0 0 0 0 0 0 0 0 O 0 0  76 69 63 77 69 63 77 71 72 73 70 69 77 69 68 74 68 64  19 9  2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2  6 6 6 6 6 6 6 6 6 6 6 6  2 2 2 2 2 2 2 2 2 2 2 2  2 2 2 3 3 3 4 4 4 5 5 5  1 2 3 1 2 3 1 2 3 1 2 3  1 50 50 1 OO 50 2 00 00 50 1 OO 50 1 50 00 1 00  1 1 OO . 7 OO 3 50 1 1 50 9 50 7 50 9 50 7 50 5 50 1 1 50 9 50 10 00  o. o. 0 0 0 0 0 0 0 0 0 0  74 72 69 81 68 66 76 70 77 76 72 71  19 9  2  19 9 19 9 19 9 19 9 19 9  19 9 19 9 19 9  1 13 1 .28 1 18 1 13 1 28 1 18 1 13 1 28 1 18 1 13 1 28 1 18 1 13 1 28 1 18 1 13 1 28 1 18 1 13 1 28 1 18 1 13 1 28 1 18 1 13 1 28 1 18 1 13 1 28 1 18  1 . 11 1 .28 1 . 18 1 . 11 1 .28 1 18 1 .11 1 .28 1 . 18 1. 1 1 1 28 1 18 1 11 1 .28 1 18 1 11 1 .28 1 . 18 1 1 1 1 1 1 1 1 1 1 1 1  11 28 18 11 28 18 11 28 18 1 1 28 18  Appendix 8 f . N i t r o g e n m o n i t o r i n g study: 1) 2 J u l y 1985  2) 16 J u l y  1985.  139  AB c D i  1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1  1 1  1  1 2 2 2 2 3 3 3 3 4 4 4 4 5 5  1 5 1 5 2 1 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2  1 1 1 2 2 2 2 3 3 3 3 4 4 4 4 5 5 5 5  E  F  G  I  H  J  K  L  M  N  0  1 2 . 10 2 1 .20 3 1 .00 4 1 .90 1 2 .40 2 0 .90 3 1 . 10 4 0 .95 1 1 .00 2 0 .75 3 1 .30 4 0 .80 1 1 .55 2 1 . 10 3 1 .35 4 0 .80 1 0 . 55 2 0 .85  4 .80 3 .70 4 .80 4 .30 4 . 10 5 .80 5 .20 5 . 10 5 .20 5 .40 5 .70 6 .00 5 .30 4 .30 5 .40 5 .70 4 .70 7 .20  0. 79 0. 80 0. 81 0..80 0..79 0..78 0.. 79 0. 80 0. 76 0. 79 0,,78 0. 75 0.,78 0.,79 0.,79 0.. 79 0.,78 0..78  1. 44 1. 44 1. 44 1. 44 1. 44 1.44 1. 44 1. 44 1. 44 1. 44 1. 44 1. 44 1. 44 1. 44 1. 44 1. 44 1. 44 1. 44  0,.80 0,.90 1,.20 1,.50 0,.70 0 .70 0,.60 0,.90 0,.70 0,.60 0 .65 0,.60 0,.75 0,.90 1,.35 0 .60 0,.65 0 .65  3 3 3 3 6 3 3 4 3 4 3 3 4 3 3 4 4 5  .20 .30 .80 .00 .70 .OO .60 . 10 .70 . 10 .70 .60 .00 .90 .90 .00 . 20 . 10  0. 74 0. 74 0. 75 0.,73 0. 72 0.,72 0. 75 0. 75 0..71 0.,72 0.,72 0. 73 0..73 0..72 0., 74 0..71 0.,70 0,.71  1 .46 1 . 46 1 . 46 1 . 46 1 .46 1 . 46 1 .46 1 .46 1 . 46 1 . 46 1 . 46 1 .46 1 .46 1 .46 1 .46 1 .46 1 .46 1 .46  0. 55 0. 75 0. 95 1,. 10 0. 60 1.,25 0.,80 0. 55 0..50 0.,55 0.,60 0.,65 0.,50 0.,65 1.,30 0,. 50 0,.70 0 .80  2. 00 0. 66 2.. 10 0. 68 2 .40 . 0. 64 1 ,. 90 0. 67 2 ,90 . 0. 68 2 .40 0. 68 2 .60 , 0. 70 2 .90 . 0. 70 2 . 30 0. 67 3 .40 0. 67 1 .20 0. 68 3 .00 0. 67 2 .60 0. 69 3 . 10 0. 68 2 .40 0. 68 2 . 10 0. 68 3 .80 0. 68 3 .60 0..67  1 ,22 , 1 ,, 22 1 .22 1 ., 22 1 .22 . 1 . 22 1 .22 1 ., 22 1 . 22 1 . 22 1 .22 1 .22 1 .22 1 .22 1 .22 1 . 22 1 . 22 1 .22  3 4 1 2 3 4 1 2 3 4  4 .80 5 .60 2 .50 2 .50 2 .50 2 .50 4 .00 4 .00 4 .00 4 .00 3. 5 3 .5 3.. 5 3 .5 3..0 3..0 3..0 3 .0 . 3..0 3 .0 . 3. 0 3.,0  0. 79 0., 78 0. 72 0.,72 0. 72 0. 72 0. 73 0. 73 0. 73 0. 73 0. 73 0. 73 0. 73 0. 73 0. 74 0. 74 0. 74 0. 74 0. 74 0. 74 0. 74 0. 74  1. 44 1. 44 1. 14 1. 14 1. 14 1. 14 1. 14 1. 14 1. 14 1. 14 1. 14 1. 14 1. 14 1. 14 1. 14 1. 14 1. 14 1. 14 1. 14 1. 14 1. 14 1. 14  0..55 0..80 2..00 2 .00 2 .00 . 2 , .00 1 .50 . 1 .50 . 1 .50 , 1 ,. 50 1 .5 . 1 .5 . 1 ,5 . 1 .5 . 1 .0 1 .0 1 .0 1 .0 2. 5 2. 5 2. 5 2. 5  4 3 6 6 6 6 7 7 7 7 6 6 6 6 5 5 5 5 8 8 8 8  .40 .90 .00 .OO .00 .00 .00 .00 .00 .OO .0 .0 .0 .0 .0 .0 .0 .0 .0 .0 .0 .0  0,, 74 0,.72 0,,67 0,.67 0..67 0. 67 0. 66 0..66 0.,66 0.,66 0. 67 0.,67 0. 67 0.,67 0. 69 0. 69 0. 69 0. 69 0. 69 0. 69 0. 69 0. 69  1 .46 1 . 46 1 . 28 1 . 28 1 . 28 1 . 28 1 .28 1 . 28 1 .28 1 .28 1 .28 1 .28 1 .28 1 .28 1 . 28 1 . 28 1 .28 1 .28 1 . 28 1 .28 1 .28 1 .28  0 0 2 2 2 2 2 2 2 2  .65 . 50 .00 .00 .00 .00 .00 , .00 , .00 .00 , 1 .5 , 1 .5 , 1 ,5 , 1 ., 5 2 , ,0 2 , .0 2 , .0 2..0 2 . 5 2.. 5 2 . .5 2..5  4 .00 3 .20 8 .00 8 .00 8 .00 8 .00 8 .50 8 . 50 8 .50 8 . 50 7 .5 7. 5 7 .5 7. 5 7 .5 7 .5 7 .5 7. 5 9 .0 9 .0 9 .0 9..0  1 .22 1 . 22 1 . 18 1 . 18 1 . 18 1 . 18 1 . 18 1 . 18 1 . 18 1 . 18 1 . 18 1 . 18 1 . 18 1 . 18 1 . 18 1 . 18 1 . 18 1 . 18 1 . 18 1 . 18 1 . 18 1 . 18  1 2 3 4  1 2 3 4 1 2 3 4  0 .95 0 .90 2 .00 2 .00 2 .00 2 . .00 2 .00 . 2..00 2..00 2 . .00 2 . 5 2 . .5 2 . ,5 2..5 3..0 3 . .0 3..0 3 . .0 3 .5 3..5 3. 5 3. 5  0..69 0,.70 0..60 0..60 0..60 0,.60 0..66 0.,66 0,,66 0,,66 0,,68 0,,68 0..68 0, 68 0, 68 0,.68 0..68 0. 68 0.,69 0. 69 0.,69 0. 69  Year (1=1984, 2=1985) B l o c k (1-5) Treatment (1=0, 2=50, 3=100, 4=200 kg ha = Depth 1 (0-20cm) H - K = Depth 2 (20-50cm) L-O = Depth 3 (50-80cm)  A = B = C = D-G  D, H , L E, I,M F, J ,N G, K ,  = N H -N ( g g _ ~ ^ moist s o i l ) moist s o i l ) = NCXT-N ( g g = Dry s o i l as a p r o p o r t i o n o f moist  N)  1  = Bulk d e n s i t y  soil  ( g cm )  Appendix 9a. R e p l i c a t e d f e r t i l i z e r S o i l data, p r e p l a n t .  response  trial:  140  A B  c  1 1 1 1 1 1 1 1 1 2 1 2 1 2 1 2 1 3 1 3 1 3 1 3 1 4 1 4 1 4 1 4 1 5 1 5 1 5 1 5 2 1 2 1 2 1 2 1 2 2 2 2 2 2 2 2 2 3 2 3 2 3 2 3 2 4 2 4 2 4 2 4  1 1 30 08 2 0 85 08 3 0 85 10 4 0 80 09 1 0 95 12 2 0 90 12 3 0 75 12 4 0 95 12 1 0 95 15 2 0 70 13 3 0 85 10 4 1 20 15 1 1 15 10 2 1 25 1 1 3 0 75 10 4 1 05 13 1 0 65 1 1 2 2 60 14 3 0 85 1 1 4 0 75 11 7 1 0 75 7 2 0 80 3 1 30 10 4 1 00 9 1 0 80 9 8 2 1 30 3 1 00 10 4 0 70 9 1 0 7 12 8 2 0 6 3 0 7 10 4 0 8 11 1 0 8 10 2 2 1 12 3 0 5 10 4 0 8 10  7 8 1 0 0 3 1 4 2 5 6 5 4 4 2 2 0 8 8 4 3 3 3 8 7 3 2 8 50 15 20 65 75 75 50 65  0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0  2 2 2 2  1 0 5 2 0 5 3 0 6 4 0 4  11 1 1 13 1 1  90 65 40 00  0 78 0 77 0 73 0 71  5 5 5 5  E  D  F 80 .80 82 81 .81 .80 .80 81 80 80 82 81 80 81 .81 .80 81 80 81 81 76 76 75 80 75 75 76 75 75 70 76 76 74 74 76 76  Appendix 9 b .  G  1  H  J  L  K  1 . 30 1 .30 1 .30 1 .30 1 .30 1 .30 1 .30 1 .30 1 .30 1 .30 1 .30 1 .30 1 .30 1 .30 1 .30 1 .30 1 .30 1 .30 1 .30 1 .30 1 . 11 1. 1 1 1 . 11 1. 1 1 1. 1 1 1. 1 1 1. 1 1 1 . 11 1 . 11 1. 1 1 1 . 11 1. 1 1 1. 1 1 1. 1 1 1. 1 1 1 . 11  0 60 0 60 0 90 0 65 0 .70 1 45 0 70 0 85 0 85 0 50 0 85 0 75 2 05 0 80 0 75 1 15 0 60 0 90 0 60 0 65 0 80 0 50 0 90 0 50 o 40 0 70 0 60 0 60 0 40 0 40 0 40 0 40 1 OO 1 40 0 30 1 00  4 4 5 3 6 6 6 6 7 5 6 5 6 6 5 5 6 8 6 5 5 4 5 3 6 6 7 7 8 6 9 9 7 8 8 9  6 1 2 8 1 0 0 0 1 7 0 7 1 8 0 1 2 9 7 0 5 8 0 8 2 3 2 0 5 8 0 9 2 9 3 0  0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0  73 75 74 75 76 74 74 76 73 73 73 73 75 73 76 71 74 71 75 75 69 68 75 66 69 66 70 67 66 75 75 70 68 72 66 67  1 .46 1 .46 1 .46 1 .46 1 .46 1 . 46 1 .46 1 .46 1 .46 1 .46 1 .46 1 .46 1 .46 1 .46 1 . 46 1 . 46 1 .46 1 .46 1 .46 1 .46 1 . 28 1 .28 1 .28 1 .28 1 .28 1 .28 1 .28 1 .28 1 .28 1 . 28 1 . 28 1 . 28 1 . 28 1 . 28 1 . 28 1 .28  0 0 1 0 0 0 0 0 0 1 0 0 2 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0  1. 1. 1. 1.  0 0 1 0  70 50 00 40  10 9 15 10  5 7 2 9  0 0 0 0  71 70 75 71  1 .28 1 . 28 1 . 28 1 .28  0 0 0 0  11 1 1 1 1 1 1  Replicated Soil  fertilizer  data. sidedress.  55 45 05 50 70 55 60 40 85 00 85 45 40 55 65 15 60 85 75 75 60 60 60 50 30 70 60 60 70 20 20 30 80 30 60 20 20 20 40 40  M 3 3 4 2 5 4 4 6 4 4 4 4 3  0 2 3 6 4 5 3 2 2 0 2 3 8 4 2 3 6 6 3 4 5 3 4 6 6 5 3 4 5 5 0 3 a 3 2 4 5 6 9 6 9 6 9 11 4 7 0 7 5 6 2 9 . 4 6 8 10 0 11 0 1 1 3 10 4 10 3 9 8  response  N 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0  68 68 69 66 68 68 69 72 69 66 69 68 69 68 69 68 68 67 68 67 66 63 63 65 69 66 65 64 66 66 65 70 71 71 64 '66 72 69 69 71  0 1 . 22 1 .22 1 .22 1 . 22 1 .22 1 . 22 1 .22 1 .22 1 .22 1 . 22 1 .22 1 . 22 1 . 22 1 .22 1 .22 1 . 22 1 .22 1 .22 1 .22 1 .22 1 . 18 1 . 18 1 . 18 1 . 18 1 . 18 1 . 18 1 . 18 1 . 18 1 . 18 1 . 18 1 . 18 1 . 18 1 . 18 1 . 18 1 . 18 1 . 18 1 . 18 1 . 18 1 . 18 1 . 18  trial:  141  AB c D i 1 1 1 1 1 1 1 1 2 1 2 1 2 1 2 1 3 1 3 1 3 1 3 1 4 1 4 1 4 1 4 1 5 1 5 1 5 1 5 2 1 2 1 2 1 2 1 2 2 2 2 2 2 2 2 2 3 2 3 2 3 2 3 2 4 2 4 2 4 2 4 2 5 2 5 2 5 2 5  E  1 1 .8 3 .0 2 1.5 8.5 14 .0 3 1 .5 411 .0 8 .0 6 .5 1 1 .8 2 2 .5 8 .0 3 2 . 4 13 .0 4 2 .0 22 .5 6 .0 1 2 .8 210 . 4 1 1.0 8 .0 3 2 .4 4 2 . 5 18 .0 1 1 .8 7 .0 8 .5 2 1 .8 8 .0 3 2 .0 4 1 .6 9 .0 9 .0 1 2. 1 2 3 .0 8 .0 3 3 .5 15 .0 4 2 .4 15 .0 1 .9 1 1 .0 2 2 .3 2 .3 3 1 .2 6 .8 4 1 .0 2 .8 4.4 1 0 .8 5 .0 2 0 .9 1 .4 3 0. 6 4 1 .3 3.4 1 .9 1 0. 7 2 1 .0 2 .4 1 .5 3 0. 7 4 1.2 2.8 1. 3 1 2. 2 4 .8 2 3. 2 4.5 3 1 .7 4 1.2 5.5 1 1.4 3 .8 2.3 2 0 .9 4.8 3 2. 1 4 1 .3 2 .5  F  G  H  1  0 .79 0 .80 0 .80 0 .80 0 .80 0 .79 0 . 79 0 .81 0 . 78 0 .79 0 .80 0 .80 0 .80 0 .79 0 .81 0 .79 0 . 79 0 . 78 0 .80 O .80 0 . 77 0 .79 0 .75 0 .75 0 .77 0 .77 0 . 75 0 .75 0,. 76 0.. 77 0 . 77 0,. 77 0 .78 0 .78 0.. 73 0,. 78 0.. 78 0.. 78 0.. 78 0..79  1 .03 1 .03 1 .03 1 .03 1 .03 1 .03 1 .03 1 .03 1 .03 1 .03 1 .03 1 .03 1 .03 1 .03 1 .03 1 .03 1 .03 1 .03 1 .03 1 .03 1 . 13 1 . 13 1 . 13 1 . 13 1 . 13 1 . 13 1 . 13 1 . 13 1 . 13 1 . 13 1 . 13 1 . 13 1 . 13 1 . 13 1 . 13 1 . 13 1 . 13 1 . 13 1 . 13 1 . 13  1 .6 1. 3 1. 2 2 .4 1 .4 1. 2 1 .0 1 .4 2. 1 1 .6 2 .0 1 .6 1 .2 1 .5 1. 1 1 .6 0.7 1 .3 1 .5 0 .8 2 .0 1 .0 0 .9 1 .5 1. 2 0 .8 1. 1 1. 1 0.7 0.7 0 .8 0 .9 0 .6 0 .8 0 .8 1. 3 1 .9 1 .0 0 .8 0.7  1. 3 1 .8 3 .7 1 .8 1 .8 2. 1 2.4 2.9 1 .8 2 .3 2.2 2 .5 1 .8 2 .4 2.. 5 2 .7 1 .7 1 .5 . 3..4 .7 3. 2..9 4..4 2.. 5 7,5 4. .9 6..3 3.. 5 .9 5. 4. .5 4. 8 5. .0 4. 9 4. 6 6..4 6. .3 .4 8. 6..4 5 .8 7.,9 7 .8  Appendix 9c.  J  K  L  0 .71 0 . 75 0 . 77 0 .73 0.. 78 0 .72 0 .73 0.. 75 0 . 72 0,.72 0.. 72 0..72 0..74 0 .73 0,. 76 0..73 0..73 0..70 0..75 0.. 74 0..70 0.,82 0..68 0..67 0.,71 0..69 0.,71 0.,69 0.,67 0. 71 0..69 0..70 0. 69 0..70 0..66 0. 68 0..71 0..73 0. 73 0. 71  1 .46 1 .46 1 .46 1 .46 1 . 46 1 .46 1 .46 1 .46 1 .46 1 .46 1 .46 1 .46 1 .46 1 .46 1 .46 1 .46 1 .46 1 .46 1 .46 1 .46 1 .28 1 .28 1 .28 1 .28 1 .28 1 .28 1 . 28 1 .28 1 .28 1 .28 1 .28 1 .28 1 .28 1 .28 1 .28 1 .28 1 .28 1 .28 1 .28 1 . 28  1 .6 1 .6 1 .4 4 .6 1. 4 2.7 2 .0 1 .2 3 .0 2 .0 2.2 3 .3 0 .9 1 .4 1. 3 1 .4 1 .9 2. 1 2 .2 1. 1 0 .8 1 .0 0 .8 1 .5 0.5 0 .8 0 .8 1 .0 0 .5 0.5 0.4 0 .6 2 .8 0 .6 0 .4 0 .5 3 .5 0 .6 1 .4 0.7  <  Replicated f e r t i l i z e r Soil  data,  harvest.  M 1 .0 1. 7 2 .2 1 .8 2.3 1 .6 3.3 3 .0 1 .5 2 .7 2. 1 2 .3 1 .9 3 .4 2.7 2. 1 1 .8 1 .8 2 .2 2 .3 1 .8 2 .9 1 .3 2 .5 1. 5 2 .2 1 .5 2 .8 3.3 1. 3 3 .6 1. 1 2. 1 4.3 3 .3 5 .2 4 .9 3 .8 8 .9 8 .5  response  N 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0  .67 .71 .71 .68 .69 .66 .69 .71 .68 .65 .69 .67 .69 .68 .70 .68 .69 .66 .68 .68 .65 .85 .65 .63 .68 .68 .63 .63 .66 .68 .65 .66 . 72 .72 .63 .65 .72 .73 .70 .70  0 1 .22 1 . 22 1 .22 1 .22 1 .22 1 . 22 1 .22 1 . 22 1 .22 1 .22 1 .22 1 .22 1 .22 1 .22 1 . 22 1 . 22 1 .22 1 .22 1 .22 1 .22 1 . 18 1 . 18 1 . 18 1 . 18 1 . 18 1 . 18 1 . 18 1 . 18 1 . 18 1 . 18 1 . 18 1 . 18 1 . 18 1 . 18 1 . 18 1 . 18 1 . 18 1 . 18 1 . 18 1 . 18  trial:  AB CD  E F  G  H  1  J  K  L  M  6 .34 4 . 98 5 .98 6 . 15 5 .61 6 .54 5 .56 6 .63 6 .29 5 .37 5 .93 5 .98 6 .63 6 .00 . 5..93 5,.93 6..95 6,.83 6 .27 6 .20 5,.25 5,. 12 5,.60 5 ,.28 5,.23 6,.03 5,.58 6,.45 6 .88 5 ,. 72 6,.85 6.. 1 1 5,.81 5 ..63 7 ,. 19 6,.76 5,.76 5,. 15 5,.92 5.,81  0 . 23 0 .21 0 .22 0 .22 0 . 23 0 .22 0 .20 0 .22 0 .23 0 .22 0 . 25 0 . 23 0 .23 0 . 22 0 .22 0 .21 0 .24 0 . 22 0 .20 0 .23 0 .24 0 .24 0 .23 0 .23 0 .21 0 . 22 0 .21 0 .21 0 .23 0 . 22 0 . 25 0 .23 0 . 20 o . 19 0 . 23 o .22 0 .21 0 .20 0 .23 0 .21  N  0  1 1 1 1 1 1 i 1 1 2 1 2 1 2 1 2 1 3 1 3 1 3 1 3 1 4 1 4 1 4 1 4 1 5 1 5 1 5 1 5 2 1 2 1 2 1 2 1 2 2 2 2 2 2 2 2 2 3 2 3 2 3 2 3 2 4 2 4 2 4 2 4 2 5 2 5 2 5 2 5  2 3 4  24 22 29 26 24 27 27 28 28 25 25 24 30 24 27 28 28 34 34 26 19 20 22 21 25 26 26 26 28 25 23 26 28 30 30 27 25 25 21 24  A B C D E F G H I J K L M N 0  = = = = = = = = = = = = = = =  Year (1=1984, 2=1985) B l o c k (1-5) _ Treatment (1=0, 2=50, 3=100, 4=200 kg ha N) Number s t a l k s Number o f cobs Number o f t i l l e r s _ S t a l k weight, f r e s h ( t ha ) S t a l k weight, dry ( t ha > S t a l k d r y matter ( p r o p o r t i o n ) S t a l k %N _ Cob weight, f r e s h ( t ha ) Cob weight, d r y ( t ha ) Cob d r y matter ( p r o p o r t i o n ) Cob %N _ Tops weight, d r y ( t ha )  1  2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1  2 3 4 1 2 3 4 1  2 3 4 1 2 3 4 1  18 15 15 19 19 18 20 17 18 19 20 19 19 18 19 19 21 20 19 16 22 22 25 27 19 22 16 22 19 18 18 18 22 17 21 17 21 18 18 19  23 27 21 20 24 29 27 25 28 26 32 29 31 25 30 29 36 33 36 27 22 20 24 15 30 34 23 37 40 33 33 35 33 34 38 36 41 26 34 26  35 .41 7 . 37 32 .07 6 . 29 36 . 59 7 . 56 42 .59 8 .61 39 . 27 8 . 10 37 .61 7 .49 37 .61 8 . 17 36 .59 7 .49 40 .93 9 .34 35 .95 7 . 54 40 .24 7 .95 38 . 73 9 .83 40 .93 8..78 35 . 4 1 7 . 24 36 . 59 7 .95 38 . 17 7 . 10 40. .93 8..51 39 .83 8 .37 36,.59 8 . 15 34 .85 6 .83 36 .54 6 .21 37, .65 6..02 37, ,65 6..02 32..67 5 ,. 55 27 ..68 4 .98 , 35 ..99 5 . 76 , 26..58 4 .25 35 ..43 5..31 34 . 33 4,,46 29 .,90 4.. 78 32,. 1 15 . 14 29. .90 5 ,.08 29. ,90 4., 19 24 . 36 3 ,. 90 36 . 00 6 ,. 12 32., 1 1 5 . 14 34 . 33 5 ..84 28 ., 24 4 .80 . 33 ..22 5 .,32 32 . 1 1 5.,46  0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. o. 0. o. 0. 0. 0. o.  17 17 18 17 17 17 17 17 19 18 18 20 19 17 18 16 18 18 19 16 17 16 16 17 18 16 16 15 13 16 16 17 14 16 17 16 17 17 16 17  0 .748 23 . 24 o .917 20 . 76 1 . 358 26 .00 1 .223 23 .78 1 .273 21 . 29 1 . 256 26 .00 1,. 173 23 .24 1,.092 26 .00 0,.972 24 .07 1 . 184 21 .29 1 .082 23 .78 1,. 268 22 .68 0,.970 24 .07 1,.205 21 ., 29 0,. 723 22 .95 1,. 121 23 .78 1,,015 25, .80 1,. 186 26 .83 1..200 27 .93 1,. 188 23 .78 0..715 21 .87 0..780 21 ., 32 0..764 24,. 36 0..918 22 .98 0..691 24,.91 0.. 94 1 27 .41 0,.975 26,.58 1..062 30, .73 0..898 29. .90 0.,874 26 ..02 1..096 27 .41 1,, 153 26 . 58 0.,903 29. .07 1., 142 29. .62 . 0.,927 31 .28 1.. 189 30 .73 1..276 27 .41 1., 186 25. . 75 1.,403 25, .75 1., 153 27 ,.68  1 .051 0 .80 1 . 348 0 . 78 1 .096 0 .64 1 . 183 0 .98 1 .220 0 .89 1 .079 1 . 17 1 .010 0 .97 1 . 140 0 .95 1 .342 0 .94 1 . 181 0 .71 1 . 397 0 .87 1 . 183 1 .62 1 .488 0 .93 0 .451 1 .OO 1 . 181 0 .91 1 . 136 0 .40 1 .485 , 0 . 79 1 .472 , 0 .69 1 ., 304 0,.51 1 .325 0 .52 1 .221 0 .83 1 ., 27 1 0,.69 1 ., 286 0,.92 1 ., 333 1,.08 1 . 182 1,.35 1 .296 1,.29 1 .267 1,. 13 1 .411 , 1,.40 1 ., 359 1 .68 1 . 166 1,.06 1 .358 1 .04 1 ., 195 1 .30 1 .298 , 1,. 18 1 ., 380 0,.91 1 .465 , 1 .49 1 .515 1 .48 1 .375 , 1 .06 1 .543 , 1,. 16 1 .408 , 1,.25 1 ., 424 1,.01  1  1  1  1  Appendix 10. R e p l i c a t e d f e r t i l i z e r response t r i a l : Com data.  143  c  AB i 1  1  1 1 1 1 1 1 1 1  2 3 4 5  1 1 1 1 1  2 3 4 5 1 2 3 4 5  2 2 2 2 2  2 3 4 5  1 1 1 1 1 2 2 2 2 2 2 2 2 2 2  2 2 2 2 2  1  1  D  1 . 2 4 .0 1 . 1 4 .0  3.5 4 .0 1 . 1 5 .0 1 . 2 4 .0 3.5 0.9 1 . 2 3 .0 4 .0 2. 1 4 .0 0.8 4 .0 2.0 4 .0 2.0 2 .5 4.5 2.5 3 .5 2 .5 3.5 4 .5 2.0 6 .5 3.0 3.0 6 .5 2 . 5 3 .5 1 .0 4 . 5 0.9 0.7  F  E 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0  78 79 76 77 76 79 80 78 77 76 74 74 74 71 63 69 74 68 75 75  G  H  1 . 27 1 . 28 1 .00 1 . 10 1 . 25 1 . 39 1 . 27 1 . 28 1 .OO 1 . 10 1 .09 1 . 14 1 .09 1 . 14 1 .21 1 . 18 1.09 1 . 14 1. 0 9 1 . 14  0.6 0.9 0.7 0.7 0.7 1 .0 0.7 0.7 0.8 0.7 2.0 2.0 2.5 2.5 2.5 2.0 2.5 2.0 3.0 0.5  I 2 3 3 3 5 3 3 3 4 4 4 8 8 7 7 4 6 9 6 8  5 0 0 0 0 0 0 0 0 0 0 0 0 0 5 0 0 0 0 0  K  J o 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0  70 76 71 75 72 74 75 75 75 74 66 67 68 70 66 64 67 67 68 70  1 46 1 41 1 46 1 41 1 46 1 41 1 46 1 41 1 46 1 .41 1 .25 1 .31 1 .25 1 .31 1 . 25 1 .31 1 . 25 1 .31 1 . 25 1 .31  L 0 0 0 0 0 0 0 0 0 0 2 2 2 2 2 2 2 2 2 0  .5 .8 .6 .7 .6 .7 .8 .5 .7 .6 .0 .0 .5 .0 .0 .0 .0 .0 .5 .5  M  A = Year (1=1984, 2=1985) B = Block (1-5) C = Treatment (1=0, 2=50, 3=100, 4=200 kg ha Depth 1 (0-20cm) Depth 2 (20-50cm) Depth 3 (50-80cm) -1 g g_,j moist s o i l ) D, H , L = N H - N moist s o i l ) g g E, I, M = N O ^ - N F, J , N = Dry s o i l as a p r o p o r t i o n o f moist G, K , C = Bulk d e n s i t y (g cm )  O 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0  2.0 2.5 2 .5 3.0 4.5 2.5 3.0 2.5 3.5 3.0 3.5 10.5 8.5 7.5 10. 5 3.5 6.0 9.5 8.0 10.5  N  0  67 67 67 65 66 69 67 68 67 66 64 62 69 71 65 64 63 62 69 70  1 .05 1 . 15 1 .05 1 . 15 1 .05 1 . 15 1 .05 1 . 15 1 .05 1 . 15 1 . 18 1 . 17 1 . 18 1 . 17 1 . 18 1 . 17 1 . 18 1 . 17 1 . 18 1 . 17  Nj  D-G H-K L-O  soil  Appendix 11a. P r e p l a n t v e r s u s s i d e d r e s s u r e a S o i l data, p r e p l a n t .  trial:  144  AB c 1 1  1 1  1 1 1 1 1 1  1  2 2 2 1 2 1 2 2 1 2 1 2 1 2 1 2 1 2 2 2 2 2 2 1 1  2 2  2 2  F  D  E  2 3 4 5 1 2 3  3.7 1 . 5 2.4 1 .5 2.9 1. 5 1. 3 1 . 1 1 .4 1 .0 2.5 0.5 7.5 6.0 6.0 1 .5 0.5 1 .0  11 15 16 16 24 8 8 10 1 1 12 21 10 25 20 25 1 1 18 15  0 0 0 0 O 0 0 0 0 0 0 0 0 0 0 0 0 0  80 80 79 80 79 .81 .80 .80 .80 .80 .72 .73 .72 .71 .71 .71 .71 .70  4 5  3.0 0.5  15 . 0 0 1 1 .5 0  72 73  1  2 3 4 5 1  2 3 4 5 1  2 0 4 1 8 0 4 8 8 0 0 5 0 0 0 5 5 0  Appendix 11b.  G 1 .60 1 .46 1 .23 1 .32 1 .29 1 . 37 1 .45 1 .46 1 . 23 1 . 32 1 . 10 1 . 14 1 . 18 1 . 18 1 .04 1 .00 1 . 10 1 . 14 1 18 1 18  H  I  1 2 1 0 1 4 0  1 1 1 1 1 0 0 2 0 1 1 0 1 0  8 0 0 1 1 1 7 5 0 5 5 0 5 0 5  1 .0 0. 0  7 4 5 2 7 5 5 2 8 6 5 0 5 0 5 9 6 0 6 0 7 0 12 5 1 1 0 1 1 0 10 5 5 0 8 5 10 .5  0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0  10 0 9 5  0. 68 0. 70  P r e p l a n t versus S o i l data,  K  L  M  1 . 46 1 .41 1 .46 1 .41 1 .46 1 .41 1 .46 1 .41 1 .46 1 .41 1 .25 1 .31 1 .25 1 .31 1 .25 1 .25 1 .31 1 .25  1 .6 1 .0 1. 2 1 .0 0.8 1 . 5 1 .0 1 . 1 0.7 1. 2 3.0 1 .5 2.0 2.0 0.5 1 .0 1 .5 1 .0  05 3 5 4 4 4 4 4 5 5 10 8 8 14 1 1 3 8 10  1 31 1 25  1 .0 0.0  9. 5 10. 5  J 74 73 74 74 73 76 73 74 71 72 64 66 68 68 65 65 64 65  s i d e d r e s s urea  sidedress.  5 8 2 8 9 4 2 5 0 0 0 0 5 0 0 0 0 0  0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0  N  0  68 68 67 67 66 71 66 68 67 66 62 63 67 74 65 66 65 .62  1 .05 1 . 15 1 .05 1 . 15 1 .05 1 . 15 1 .05 1 . 15 1 .05 1 . 15 1 . 18 1 . 17 1 . 18 1 . 17 1 . 18 1 . 18 1 . 17 1 . 18  0 69 0 72  trial:  1 17 1 18  145  AB 1  1 1 1  1 1 1 1  1 1 1 2 1 2 1 2 1 2 1 2 2 1 2 1 2 1 2 1 2 1 2 2 2 2 2 2 2 2 2 2  c 1 2 3 4 5 1  2 3 4 5 1 2 3 4 5  1 2 3 4 5  D 2.0 3 . 5 3.8 2.4 2.0 2.0 1 . G 5.6 2 . 5 2 . 9 1. 5 3.0 2.0 3 . 5 7.0 2.0 1 .0 1 .0 2 . 5 3.0  F  E 30 0 33 0 18 0 21 0 20 0 1 15 3 0 16 0 15 0 12 0 5 5 21 5 10 5 8 5 29 0 4 5 9 0 3 5 7 5 15 5  Appendix  0 0 0 0 0 0 0 0 0 0  81 .81 . 78 .81 . 79 .80 . 76 .81 .80 78 . 75 .73 77 .79 79 75 73 72 .77 .79  G 1 .25 1 . 25 1 . 25 1 . 25 1 . 25 1 . 25 1 .25 1 .25 1 .25 1 . 25 1 . 13 1 . 13 1 . 13 1 . 13 1 . 13 1 . 13 1 . 13 1 . 13 1 . 13 1 . 13  H 1 4 1 0 7 7 9 2 7 5 3 7 0 5 5 0 0 0 5 5 1 0 1 0  2 1 2 1 1 4 1 2 2 1 1 1 3 2 2  11c. P r e p l a n t Soil  1 2 2 2 3 4 1 2 3 4 2 2 7 8 7 1 1 2 5 4 8 8  J 6 4 7 7 5 7 8 5 3 4 0 5 0 5 5 5 5 0 0 5  0 0 0 0 0 0 0 0 0 0  75 74 72 76 71 74 76 74 84 71 66 68 71 71 70 66 68 69 71 72  versus  data,  K 1 .46 1 . 46 1 .46 1 . 46 1 . 46 1 .46 1 .46 1 .46 1 .46 1 . 46 1 . 28 1 . 28 1 . 28 1 . 28 1 . 28 1 . 28 1 . 28 1 . 28 1 . 28 1 . 28  L  M  4.0 2.0 3.5 1. 5 1. 2 1 .9 1 .7 2 . 2 1 .5 1 .9 1. 5 2.0 1 .0 1 .0 1 .0 1 .0 1 .5 1 .0 1. 5 1.0  2 2 1 3 2 1 2 2 3 1 1 7 3 6 5 1 3 2 3 5  N 9 9 9 9 1 4 4 6 7 1 0 0 5 0 0 0 0 5 0 5  sidedress urea  harvest.  0 0 0 0 0 0 0 0 0 0  68 69 67 68 65 70 68 68 70 66 62 63 67 72 62 64 65 64 68 72  0 1 .22 1 . 22 1 .22 1 .22 1 .22 1 . 22 1 . 22 1 .22 1 . 22 1 .22 1 . 18 1 . 18 1 . 18 1 . 18 1 . 18 1 . 18 1 . 18 1 . 18 1 . 18 1 . 18  trial:  146  AB 1 1 1 1 1 1 1  1  1 1 1 2 1 2 1 2 1 2 1 2 2 1 2 1 2 1 2 1 2 1 2 2 2 2 2 2 2 2 2 2  c  D E F  1  32 18 27 29 33 26 25 23 29 30 22 26 28 28 20 22 30 25 25 28  2 3 4 5 1 2 3 4 5 1  2 3 4 5 1  2 3 4 5  A B C D E F G H I J K L M N O  = = = = = = = = = = = = = = =  19 18 19 20 19 13 13 20 18 21 21 21 18 21 17 20 22 21 19 19  20 23 28 29 34 27 21 34 26 36 22 29 36 39 28 20 41 36 26 26  G 30 33 38 35 44 34 34 37 34 43 30 28 27 37 22 28 34 30 24 28  93 73 73 95 24 24 29 61 29 71 42 76 1 1 62 13 21 30 42 34 21  H  I  5 .41 0 5 . 73 0 6 .97 0 6 .83 0 7 . 52 0 6 . 16 0 5 .83 0 6 . 77 0 6 . 17 0 6 .99 0 4 .87 0 4 .89 0 4 .61 0 5 .64 0 3 .76 0 4 .80 0 6 . 17 0. 4 .56 0 3 .41 0. 4 .80 0  18 17 18 19 17 18 17 18 18 16 16 17 17 15 17 17 18 15 14 17  K  J 1 1 0 1 0 1 1 0 1 1 0 1 0 1 1 0 1 1 1 1  016 087 967 1 18 961 105 141 905 266 315 679 054 985 001 109 817 021 058 031 086  29 21 24 22 27 26 21 22 23 25 23 25 26 30 23 22 30 27 30 29  M  L  32 85 90 68 39 56 93 41 78 73 23 45 83 15 51 68 70 66 15 59  5 . 57 4 .81 5 . 23 4 .76 6 .03 5 .31 4 .60 4 .71 4 . 76 5 .92 5.1 1 5 .60 6 . 17 6 .63 4 .70 4 . 76 7 .06 6 . 36 6 .63 6 .21  0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0  19 22 21 21 22 20 21 21 20 23 22 22 23 22 20 21 23 23 22 21  N  0  0 . 59 1 .22 1 .22 0 .95 1 .40 1 . 10 1 .31 0 .94 1 . 19 1 . 30 1 . 25 1 .49 1 . 39 1 . 36 1 . 33 1 .22 1 .30 1 . 46 1 .27 1 .29  0. 78 0. 56 0.80 0.44 0. 85 0. 73 0. 39 0.49 0.46 0.56 1 .05 0.74 0.77 1.13 0.79 0. 89 0.92 1 .01 1 .01 0. 76  Year (1=1984, 2=1985) Treatment (1=Preplant, 2=sidedress) B l o c k (1-5) Number s t a l k s Number o f cobs Number o f t i l l e r s _ S t a l k weight, f r e s h ( t ha ) S t a l k weight, d r y ( t ha ) S t a l k d r y matter ( p r o p o r t i o n ) S t a l k %N _ Cob weight, f r e s h ( t ha ) Cob weight, d r y ( t ha ) Cob d r y matter ( p r o p o r t i o n ) Cob %N _., Tops weight, d r y ( t ha ) 1  n  Appendix 12. P r e p l a n t v e r s u s s i d e d r e s s urea t r i a l : Corn d a t a .  YR  SITE  1 1 1 2 1 3 1 4 1 5 1 6 1 7 1 8 1 9 1 10  1 11  1 1 1 1 1 1 2  12 13 14 15 16 17 1  2 2 2 2 2 2 2 2 2  2 3 4  2  5 6  7 8 9  10 1 1  0M1  2 2 2 3 3 4 3 3 4 3 4 7 3 3 3 9 2 4 7 16 3 7 6 5 5 4 3 4  3 3 2 0 7 4 6 8 7 6 4 4 9 2 6 5 4 4 0 0 4 8 8 4 1 0 8 1  0M2  0M3  2 2 4 1 4 3 3 4 3 3 1 2 3 3  3 1 1 4 3 3 4 4 3 4 1 1 1 2  1 1 1 3 1 2 3 1 2 2 3 2 2  5 0 1 9 4 8 G 0 8 7 6 2 0 2 8 7 9 8 3 8 3 6 6 0 8 1 1 2  1 1 1 2 1 3 2 1 1 2 2 2 2  4 8 5 1 6 6 6 2 6 2 5 7 8 6 7 7 9 5 3 9 0 8 0 8 5 5 6 0  SON)  SONS  .3 .2 .3 .2 .2 .3 .3 .4 .4 .4 .4 .5 .4 .1 .2 .4 .2 .2 .3 .7 .1 .2 .3 .2 .2 .2 .2 .2  .1 .1 .2 .1 .1 .1 .1 .3 .3 .3 .3 .3 .3 .1 .0 .2 .2 .1 . |  .1 .1 .1 . l  .1 .1 .1 .1 • 1  S0N3  .1 .1  .1 .1 .1 .1 .1 .2 .2 .3 .3 .3 .1 .1 .2 .2 .2 .1 .1 .1 .1 .1 .0 .0 .1 .1 .1 .1  PHH201 PHH202  4 4 4 5 4 4 5 5 4 4 4 4 4 4 5 5 5 6 5 6 5 6 5 6 6 6 4 5  9 5 8 2 3 9 6 0 8 7 7 4 3 1 2 6 0 1 0 4 8 9 8 0 0 1 8 8  3 3 4 4 3 5 5 4 4 4 4 4 3 3 6 4 4 5 5 6 6 5 6 5 6 5 4 5  9 7 4 5 8 3 7 5 0 0 5 3 8 6 6 1 3 8 8 4 2 8 7 0 5 1 6 8  PHH203  3 5 1 O 4 4 2 3 4 3 5 5 3 5 5 4 1 4 2 3 6 4 3 4 5 3 5 3 2 6 6 3 9 3 8 5 2 5 8 5 9 4 8 4 4 5 9 4 5 5 9 4 2 4 3 5 4  SA1  0 2 0 O 2 0 0 9 0 6 0 12 0 1 10 12 0 8 0 6 O 6 0 8 0 9 0 8 0 5 0 4 0 4 O 36 0 5 0 6 0 10 0 8 0 12 0 2 0 1 0 2 0  SA2  SA3  0 6 O 4 O 0 14 0 8 0 14 0 8 0 6 0 6 0 14 0 3 0 4 0 6 0 6 0 3 0 6 0 9 0 2 0 6 0 2 0 3 0 14 0 10 0 2 0 0 6 0 5 0  4 0 2 0 4 0 0 32 0 14 0 17 0 26 0 35 0 9 0 17 0 6 O 6 O 15 O 26 0 10 0 13 0 9 O 4 0 14 0 5 0 8 0 18 0 17 0 2 0 IO 0 4 0 0  SI 1 76 69 68 70 63 65 72 60 59 61 65 64 74 73 71 72 75 71 70 49 73 68 66 70 58 64 69 62  0 0 O O 0 0 O 0 0 O 0 O 0 0 0 O 0 0 0 0 0 0 0 0 0 0 0 o  SI2 73 72 70 75 71 68 70 67 67 69 72 69 75 74 78 81 76 74 72 72 72 72 62 72 67 70 73 71  0 0 0 0 0 0 0 0 0 0 0 O 0 0 0 0 0 0 O 0 0 0 0 0 0 0 0 o  YR = Year (1=1984, 2=1985) 1 = Depth 1 (0-20cm) 2 = Depth 2 (20-50cm) 3 = Depth 3 (50-80cm) OM = Organic matter (%) SON = T o t a l s o i l N (%) P H = PH (H 0) SA = Sand t%) SI = S i l t (%) CL = C l a y (%) 2  Appendix 13a. M u l t i f a r m t r i a l : S i t e p r o p e r t i e s .  SI3 76 80 74 76 57 69 67 60 55 73 70 77 76 69 60 77 74 71 72 68 71 70 62 70 71 70 72 74  0 O 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0  Cl.  24 29 32 28 37 26 22 28 30 27 27 30 20 19 20 20 20 25 26 15 22 26 24 22 30 34 30 36  1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0  CL2 27 22 26 25 15 24 16 25 27 25 14 28 21 20 16 16 18 20 26 22 26 25 20 18 31 30 21 24  0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 o  CL3 20 0 18 0 22 0 24 0 1 1 0 17 0 1G 0 14 0 10 0 18 O 13 0 17 0 18 0 16 0 14 0 13 0 13 0 20 0 24 0 18 0 24 0 22 0 20 0 13 0 27 0 20 0 24 0 26 0  YR  ,  1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 2  SITE 1 2 3 4 5 6 7 8 9 10 1 1 12 13 14 15 16 17 1 2 3 4 5 e 7 8 9 10 1 1  NA 1 .05 . 88 .05 . 27 .01 .00 2 . 66 .00 .OO .00 .00 .00 .03 .00 . 49 4 . 28 .00 . 16 . 17 .21 .21 . 44 . 33 1 .94 . 17 . 26 . 20 .06  MA 2 02 90 29 22  OO 14 4 97 05 15 00 00 00 36 23 2 45 5 35 00 16 33 37 . 20 1 34 1 14 2 92 1 1 17 1 02 10  NA3 .00 1.13 . 56 .09 .00 .84 7.17 .05 .54 .01 .00 .02 . 13 .01 3.15 6 . 43 .00 .2 1 . 93 . 46 .40 3.76 2 . 79 4 . 65 . 10 . 17 .42 . 12  CA TS 1 CATS2 8 7 7 8 4 8 1 1 6 5 5 5 5 5 5 9 17 6 9 3 15 7 16 8 10 10 8 3 7  40 84  1 2 31 2 05 3 25' 1 12 7 39 1 1 98 4 85 2 75 1 14 3 19 4 1 1 2 48 1 7 1 10 97 10 37 3 17 6 93 5 54 7 39 6 89 9 96 8 06 6 4 1 8 69 3 79 3 33 4  CATS3  28 73 79 3 1 1 3 13 50 28 1 82 40 1 63 95 5 94 62 13 63 22 2 34 07 3 54 96 49 57 3 72 22 4 50 56 1 23 58 1 02 38 8 65 16 1 1 03 37 1 19 4 27 40 56 5 76 6 43 19 55 2 74 95 6 68 96 8 44 76 7 88 15 5 90 7 1 1 08 37 2 05 92 4 43  XNAI XNA 2  XNA3  SAR 1  SAR2  4 4 7 8 0 8 8 2 4 0 0 1 1 3 6 7 0 5 9 1 1 5 7 2 3 6 4 0  0 36 2 17 9 4 8 0 14 1 52 6 2 0 15 2 1 4 1 5 10 6 8 36 4 58 3 0 4 9 6 2 7 1 14 7 56 3 33 0 59 0 1 6 16 1 20 6 2 7  .024 . 485 .029 . 138 .009 .000 1 . 320 .002 .000 .000 .000 .000 .017 .000 . 234 1 .686 .000 .079 . 1 38 .088 .114 . 157 . 160 .990 .07 7 . 129 . 163 .033  .023 .980 . 296 . 184 .OOO .075 2 . 833 .030 . 163 .000 .000 .003 . 365 .291 1 . 252 3 .627 .000 .093 . 209 .241 .115 .656 .581 2 . 200 .057 .13 1 . 999 .066  6 1 1 2 7 3 3 3 0 23 4 1 0 0 o 0 5 0 5 1 23 8 0 1 8 4 4 1 4 2 8 2 6 3 6 19 3 1 6 3 0 5 4 8  1 32 1 1 6 1 42 1 7  14 14 23 52 2 5 5 3 13 12 43 1 4 30 2  SAR3 S04S1  2  4  1 4  3 1 3  000 14 6 120 1 16 5 24 7 528 097 10 3 59 9 000 547 16 6 94 4 156 048 18 8 457 14 3 02 1 21 7 003 15 3 015 14 1 19 1 18 9 013 31 3 946 19 2 4 14 136 6 18 1 000 149 34 0 624 23 O 57 0 290 395 26 0 236 64 0 698 32 0 838 1 1 1 0 26 0 06O 272 32 0 504 61 0 33 0 082  S04S2 22 150 32 17 89 12 146 15 33 33 15 12 45 60 25 17 1 24 2 1 23 37 19 92 30 14 1 20 46 177 30  3 2 6 4 8 8 3 7 6 9 6 4 2 9 8 5 3 0 0 0 0 0 0 0 0 0 0 0  S04S3 77 188 47 36 190 13 236 39 49 98 2 1 14 75 192 54 202 58 46 30 66 7 1 160 198 340 38 84 13 1 39  9 4 3 4 O 0 5 2 1 1 7 2 4 2 7 4 5 0 O 0 O 0 0 0 O O 0 0  YR = Year (1=1984, 2=1985) 1 = Depth 1 (0-20cm) 2 = Depth 2 (20-50cm) 3 = Depth 3 (50-80cm) NA = Na (me 100ml ) _ CATS = T o t a l c a t i o n s (me 100ml ) XNA = Exchangeable sodium (%) SAR = Sodium A d s o r p t i o n R a t i o SO.-S = Sulphates ( g mL ) 4 1  Appendix  13b. M u l t i f a r m  trial:  Site properties.  03  5 SITE  , 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 2  1 2 3 4 5 6 7 8 9 10 1 1 12 13 14 15 16 17 1 2 3 4 5 6 7 8 9 10 1 1  EC 1  EC2  . 32 1 . 32 . 48 . 36 . 56 . 44 1 .40 .40 . 40 .40 .40 . 48 . 36 . 48 .44 5.00 . 48 1.12 .56 1 . 32 . 56 1 .00 . 84 1 . 76 .76 . 72 . 56 .44  .40 1 . 48 . 40 . 28 .68 . 36 2 . 40 . 24 .56 . 40 .32 . 32 . 48 .60 . 56 6. 10 . 32 . 36 . 32 . 52 .24 1 . 76 . 36 4 .00 . 32 . 40 .96 .40  EC3  P1  .60 56 2.20 77 .48139 .36 72 1.68 70 .40 82 7.50 89 .32 72 .88 80 .84161 .36 65 .24 32 .64 59 1.92 97 .96 29 9.00113 .48144 .36192 .321 15 .68358 .40170 5.30131 1.84 30 6.50119 .40291 .44 121 .72 97 .32105  P2  0 0 14 00 13 OO 19 00 11 00 9 00 1 1 5 00 0 0 31 00 10 0 0 10 00 8 2 00 0 0 12 00 22 2 00 8 00 00 22 0 0 49 00 27 0 0 27 00 62 0 0 23 0 0 13 00 24 001 16 00 18 0 0 13 00 22  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  oo  00 00 00 00 00 00 00 00  P3 14 14 18 11 11 8 6 13 9 15 7 2 1 1 1 1 4 8 7 16 12 22 21 10 13 9 61 14 21 13  00 OO 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  K 1  K2  K3  . 33 . 39 . 66 .40 .43 .75 .58 .75 .56 .51 .58 .25 .42 .51 . 36 .77 .36 .64 . 58 3.48 .44 . 50 .30 .40 .97 .51 .43 .52  . 10 . 18 . 27 . 15 . 14 .47 .50 . 38 . 17 . 19 . 15 .09 . 24 . 15 .25 .46 . 18 . 29 .37 2 . 22 .31 .26 . 19 .30 . 76 . 18 . 25 . 25  . 12 . 23 . 3 1 . 13 . 16 . 39 .51 . 30 .21 . 15 . 10 .08 . 17 . 16 . 26 . 36 . 12 . 16 . 38 1 .00 . 25 . 22 .26 . 30 . 76 .09 . 23 . 17  MG 1 2 1 1 1 1 2 3 2 1  1 1 4 5 1 1 1 5 1 1 2 2 1 1  53 80 02 82 22 28 74 44 81 19 81 91 39 28 23 67 32 18 35 48 50 68 92 2 1 47 64 76 65  CA 1  CA2  CA3  . 38 5 48 1 . 10 4 76 5 57 1 24 84 5 57 95 2 60 5 09 3 55 4 1 1 4 39 1 34 3 79 4 49 1 56 41 4 05 1 .53 3 75 2 . 19 4 02 52 3 26 .42 3 .68 4 63 3 .83 3 . 19 7 25 .45 4 69 7 19 2 .05 1 83 3 .06 3 .41 6 36 1 . 26 5 24 1 .50 14 26 3 .92 5 .41 1 .95 5 51 2 . 13 7 .80 . 32 6 28 .49 2 .40 .98 6 . 10  .61 .80 1 . 23 1 66 59 2 95 2 32 1 .62 1 15 .80 2 .42 2 .66 1 .23 .82 2 . 25 1 . 29 2 .38 3 .89 2 . 10 1 .71 3 .78 6 .67 2 .68 1 .87 5 . 38 2 . 37 .85 3 .87  . 23 .66 1 .02 .76 .51 1 . 16 1 .83 .64 1 . 24 . 38 2 .08 2 . 20 .41 .44 1 .41 1 .05 .62 1 .85 1 . 38 1 .56 .83 1 . 20 1 .48 . 98 2 .91 .49 .91 3 . 16  MG2 . 55 91 7 1 1 . 24 67 4 . 39 3 84 2 . 17 .60 . 49 1 .00 1 .46 . 72 . 39 5 .43 3 .06 .81 2 .06 2 . 77 2 .89 2 .25 1 . 68 4 .95 1 .66 1 .90 1 .OO 1 . 24 .71  MG3  YR = Year (1=1984, 2=1985) 1 = Depth 1 (0-20cm) 2 = Depth 2 (20-50cm) 3 = Depth 3 (50-80cm) P = P mL ) K = K (me 100mL ) MG = Mg (me 100ml_J) CA = Ca (me 100mL ) Appendix 13c. M u l t i f a r m t r i a l :  Site properties.  YR 1 1 1 1 1 1 1  1 1 1  1 1 1 1 1  1 1  2 2 2 2 2 2 2 2 2 2 2  SITE 1 2 3 4 5 6 7 8 9 10 1 1 12 13 14 15 16 17 1 2 3 4 5 6 7 8 9 10 1 1  B 1 59 84 7 1 55 39 1 69 2 47 2 05 40 3 1 1 1 07 64 42 89 2 04 59 58 1 41 1 89 1 14 58 1 54 1 97 83 .61 1 . 24 . 43  B2 27 47 33 15 24 1 2 1 1 64 96 35 39 00 00 39 25 1 26 99 32 40 1 34 .84 1 . 19 56 1 .64 1 .21 .52 .52 .81 . 36  B3 30 51 34 13 17 72 1 97 64 29 42 00 00 55 28 1 28 1 09 23 .47 1 13 .96 1 .01 88 1 94 1 .45 .55 .84 .84 48  CU 1 5 9 9 7 1 1 3 6 2 6 6 8 6 8 1 1 4 6 6 3 2 3 3 3 1 5 4 7 7 6  5 0 3 5 0 3 7 7 3 3 4 3 0 6 0 4 8 7 3 6 9 7 6 0 8 0 9 4  CU2 6 3 8 8 6 6 10 9 5 3 8 1 1 7 6 5 17 8 5 6 6 5 7 4 8 6 7 4 6  8 7 7 9 8 5 2 9 7 9 6 3 3. 1 7 2 7 3 0 0 0 4 8 2 9 8 7 9  CU3 4 2 6 8 7 12 8 6 2 1 9 10 2 2 3 9 7 7 12 12 8 6 5 4 8 6 5 6  9 8 0 4 5 3 8 6 2 8 0 5 8 9 1 7 3 1 2 9 3 6 9 4 7 0 6 9  FE 1 123 .O 354 . 1 34 1 . 5 142 .6 507 .0 436.2 294.5 650.0 440.5 448.8 310.6 337.0 650.0 452 . 3 463. 1 321 .9 160. 2 240.0 371 .3 338 . 1 177.4 155.5 500.0 231 .6 206 . 3 126.2 312.2 244 . 4  FE2 297 315 374 163 345 163 69 336 329 465 210 315 420 390 67 392 241 133 227 136 139 267 193 235 172 313 358 215  FE3 8 4 5 6 5 5 1 8 7 7 0 5 4 6 7 2 7 8 6 7 6 8 9 3 0 0 1 9  301 315 334 282 335 209 155 324 228 444 263 309 367 402 47 494 333 189 196 164 293 363 98 290 320 273 329 2 18  8 2 0 6 7 0 3 1 2 1 9 6 4 7 8 2 2 2 1 2 6 7 0 7 8 O 2 1  MN1 22 9 4 38 1 1 2 2 7 2 9 5 5 6 9 3 14 17 1 3 7 7 1 1 1 20 18 17 2  1 7 1 2 0 4 6 2 8 0 3 6 4 3 1 7 0 5 3 2 4 3 8 5 5 9 5 7  MN2  MN3  1 3 1 3 2 1 1 5 1 1 1 1 1  2 3 2 4 2 2 1 4  1 5 4 1 3 1 1 5 4 2 1  6 1 9 8 3 3 4 2 6 7 7 4 6 9 1 5 8 8 3 5 9 1 8 3 7 3 7 3  2 1 1 1 4 1 5 2 1 3 1 4 1 1 5  5 9 5 6 9 5 1 3 9 1 6 9 6 6 9 4 1 8 9 8 1 1 6 7 0 5 5 9  ZN1  ZN2  ZN3  1 2 1 3 9 1 3 1 3 1 6 1 3 2 3 1 2 1 9 8 1 0 1 3 1 8 1 3 13 9 1 5 6 1 2 34 3 1 2 1 2 1 3 1 4 4 7 1 1 1 4 8  5 5 5 3 7 8 7 0 6 5 7 0 6 5 2 9 1 6 9 8 1 8 4 2 4 7 5 6  6 9 6 0 0 2 0 1 4 5 1 3 4 9 2 1 0 9 5 9 2 1 8 4 6 4 7 7  1  1 2  1  5 1  1  2 1  1 3 1 2 1  1 1  4 1 1 1 1 1 1  YR = Year (1=1984. 2= 1 = Depth 1 (0-20cm) 2 = Depth 2 (20-50cm) 3 = Depth 3 (50-80cm) B = B (*/g mL ) CU = Cu (-*/g mL^ ) FE = Fe (^Q mL_ ) MN = Mn (^g mL_ ) ZN = Zn (^g mL ) Appendix 13d. M u l t i f a r m  trial:  Site properties  ui o  YR SITE NH4N1S0 N03N1SO DW1 SO BD1 SO NH4N2S0 N03N2SO DW2SO BD2S0 NH4N3S0 N03N3S0 DW3S0 BD3S0 1 1  1 1 1 1  1 i. 1 1 1 1  1 1 1 1 1  2 2 2 2 2 2 2 2 2 2 2  1  2 3 4 5 6 7 8 9 10 1 1 12 13 14 15 16 17 1 2 3 4 5 6 7 8 9 10 11  2 50 50 4 20 3 00 2 60 1 10 2 50 2 20 2 00 8 10 20 1 00 2 40 1 20 5 20 1 70 1 00 2 00 2 00 3 25 2 25 2 50 2 00 7 25 2 50 2 25 2 10 80  3 2 13 2 1 8 1 9 8 1 3 8 5 3 1 1 1 1 13 14 26 1 1 9 6 4 9 9 12 8  70 00 30 50 30 60 30 80 20 00 40 00 60 40 60 60 60 00 00 00 50 00 00 00 50 50 75 40  . 77 . 75 . 75 . 78 . 75 . 77 . 78 . 75 . 73 .75 . 75 .72 . 77 . 77 . 77 . 72 . 78 . 80 . 79 . 77 . 82 . 78 .82 . 80 .80 . 79 . 76 . 76  1 41  1 38 1 32 1 35 1 52 1 32 1 34 1 12 1 37 1 20 1 25 1 03 1 25 1 22 1 24 1 08 1 30 1 43 1 23 1 04 1 48 1 17 1 12 1 26 1 30 1 25 1 13 1 15  YR = 1 = 2 = 3 = NH4N N03N DW = BD =  Appendix  3 60 1 60 20 80 80 1 70 10 1 00 1 70 1 00 10 1 00 1 90 80 90 1 50 96 1 40 70 60 40 40 60 40 70 80 1 40 85  5 00 80 4 70 1 30 40 4 30 40 3 10 3 80 20 1 50 3 20 4 60 1 00 4 90 70 6 02 8 80 4 50 5 80 4 90 4 60 6 60 1 90 4 20 12 20 8 90 5 50  . 70 .67 .67 . 72 . 70 . 77 . 77 . 78 . 70 .68 . 74 . 73 .69 .68 . 78 . 74 . 73 .81 .79 . 80 . 77 . 74 . 70 . 77 . 76 . 70 . 69 . 73  1 09 1 08 85 1 29 1 48 1 29 1 42 1 35 1 31 99 1 37 1 26 1 29 1 14 1 34 90 1 46 1 47 1 46 1 30 1 39 1 41 1 51 1 60 1 19 93 1 28 1 35  40 2 00 3 00 40 80 1 40 10 1 50 1 10 1 00 30 30 1 90 50 1 40 2 80 1 02 20 50 60 2 00 2 00 2 00 2 00 2 00 2 00 1 50 4 25  4 00 20 1 70 1 30 10 3 00 05 40 2 40 05 40 1 20 3 60 70 5 00 1 50 4 20 10 25 3 15 9 50 5 50 3 75 6 50 23 6 15 12 75 6 75 3 55  .63 .65 .65 .67 .70 . 74 .70 . 73 .75 .64 .71 . 70 .66 .68 .79 .71 .68 .71 .75 .78 .69 .70 .76 . 72 .69 .69 .66 .70  1 05 1 03 90 1 00 1 .20 1 43 1 21 1 37 1 14 1 04 1 24 1 24 1 02 1 04 1 45 1 19 1 22 1 09 1 53 1 06 1 36 1 24 1 40 1 41 1 03 87 1 18 1 31  Year (1=1984. 2=1985) Depth 1 (0-20cm) Depth 2 (20-50cm) Depth 3 (50-80cm) = NH -N ( A K J g~} ) = NO^-N (<"cj g ) Dry weight (as a p r o p o r t i o n o f moist) Bulk d e n s i t y (g cm )  14a. M u l t i f a r m t r i a l : plots  S o i l d a t a from  control  (0) a t s i d e d r e s s ( S ) . ui  YR  SITE  1  1 2 3 4 5 6 7 8 9 10 1 1 12 13 14 15 16 17 1 2 3 4 5 6 7 8 9 10 1 1  1 1  1 1 1 1  1 1 1 1 1 1 1 1  1 1 2 2 2 2 2 2 2 2 2  1  2  NH4N1S1  3 4 1 1 1 5 3 1 8  3 2 6 3 2 3 2 2 2 7 2 2 2  40 60 20 80 10 10 00 80 80 10 40 30 60 20 40 00 95 OO 20 25 25 50 00 25 50 25 10 50  N03N1S1 DW1S1 BD1S1 NH4N2S1 5 00 1 80 12 70 4 00 1 40 10 60 1 30 10 60 11 70 2 10 3 90 10 00 10 30 4 90 2 10 3 20 12 30 13 00 14 00 26 00 1 1 50 9 00 6 00 4 00 9 50 9 50 12 75 9 40  Appendix  . 75 . 74 . 74 .78 . 76 . 76 .77 . 77 . 73 . 75 . 75 . 72 . 77 . 77 . 75 . 75 . 72 . 80 . 79 . 77 .82 .78 . 82 .80 .80 . 79 . 76 .76  1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1  41 38 32 35 52 31 34 12 37 20 25 03 25 22 24 08 33 43 23 04 48 17 12 26 30 25 13 15  1 1  1 1 1  1 2 1 6 1  1  N03N2S1 5 20 80 5 30 2 00 90 4 30 10 2 80 5 10 20 2 00 3 40 5 70 1 00 5 80 3 70 5 12 8 80 4 50 5 86 4 90 4 60 1 32 6 90 4 20 12 20 8 90 5 25  20 80 40 60 60 40 10 80 30 10 30 30 80 10 50 50 81 40 70 60 40 40 60 40 70 80 40 30  14b. M u l t i f a r m plots  DW2S1 BD2S1 NH4N3S1 .69 .68 . 67 .72 .73 . 78 . 77 .78 . 70 .68 . 72 . 72 .67 .67 . 79 .74 . 73 .81 . 79 . 80 . 77 . 74 .70 .77 .76 .70 .69 . 73  trial:  1 09 1 08 84 1 29 1 48 1 29 1 42 1 35 1 31 99 1 37 1 26 1 29 1 14 1 34 90 1 46 1 47 1 46 1 30 1 39 1 41 1 51 1 60 1 19 93 1 28 1 .35  Soil  20 1 80 1 40 20 1 70 2 60 2 20 1 00 1 40 80 30 30 2 20 1 40 40 70 65 20 50 60 40 40 40 40 40 40 30 10  data  N03N3S1 DW3S1 BD3S1 4 10 20 1 40 1 30 20 2 00 05 1 80 3 30 05 70 1 40 3 60 1 40 5 00 1 00 4 94 10 25 3 15 9 50 5 50 3 75 6 50 1 15 6 15 12 75 6 75 4 95  from  . 63 .65 . 65 .67 .71 . 76 .71 .73 .75 .65 . 73 . 69 .64 .63 . 78 .71 .68 .71 . 75 . 78 .69 . 70 . 76 . 72 .69 .69 . 66 .70  1 05 1 04 90 1 00 1 20 1 43 1 21 1 37 1 14 1 04 1 24 1 24 1 02 1 04 1 45 1 19 1 22 1 09 1 53 1 06 1 36 1 24 1 40 1 41 1 03 87 1 18 1 31  fertilized  (1) a t s i d e d r e s s ( S ) .  ui  YR S I T E NH4N1H0 N03N1H0 DW1H0 BD1H0 NH4N2H0 N03N2HO DW2H0 BD2H0 NH4N3H0 N03N3HO DW3H0 BD3H0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 2  1 2 3 4 5 6 7 8 9 10 1 1 12 13 14 15 16 17 1 2 3 4 5 6 7 8 9 10 1 1  1 1 1 1 1 1 2 1 2 5 2 2 1 1 1 2 5 4 6 4 4 4 4 4 3 1 1  5 9 5 1 4 2 1 4 5 2 7 3 0 8 7 1 1 5 5 5 0 0 0 5 0 5 5 5  5 13 4 3 2 5 3 6 4 3 1 5 3 1 3 6 6 19 6 21 13 5 2 6 15 1 1 3 2  0 5 0 5 0 4 0 1 9 3 8 8 7 8 6 0 5 5 0 5 0 5 0 0 0 5 0 5  . 76 . 74 .69 .80 . 75 .81 . 73 . 77 . 73 .74 .69 . 70 . 78 . 76 . 76 . 72 .79 .81 .82 . 79 .81 .75 .70 . 76 . 78 . 75 . 77 . 76  1 1 1 1 1  22 17 17 13 09 89 1 18 98 91 1 00 1 03 76 1 01 1 03 1 08 93 1 .25 1 . 43 1 .23 1 06 1 42 1 17 1 12 1 26 1 30 1 25 1 27 1 15  1 0 8 1 1 9 8 2 1 1 3 8 1 9 5 6 1 9 1 4 1 9 9 1 4 1 9 1 4 1 0 1 5 1 5 1 0 5 1 5 5 5 1 0 1 0 1 5  3 0 2 0 1 1 5 3 9 9 1 6 2 2 1 7 7 5 1 4 7 2 7 1 1 1 8 9 0 5 5 2 5 2 5 3 5 17 0 1 0 4 5 5 5 4 5 1 5  .71 .68 .70 . 74 . 71 .81 . 78 .79 .70 .69 . 73 . 72 .69 . 70 . 78 . 74 .73 .83 .83 .86 .82 .74 .80 . 77 . 77 .71 .69 . 73  1 09 1 08 85 1 29 1 48 1 29 1 42 1 35 1 31 99 1 37 1 26 1 29 1 14 1 34 90 1 46 1 47 1 46 1 30 1 39 1 41 1 51 1 60 1 19 93 1 28 1 35  1  2 2 1 2  1  1 1 1 1 1 1 1 1 1 1  9 8 1 7 6 1 0 9 2 5 6 2 6 6 7 6 8 O 5 5 0 5 0 0 0 5 5 5  2 .0 .9 1 .O . 7 . 3 . 7 1 .0 1 .6 1 .5 1 .7 .7 . 2 1 .8 .6 2 .0 1 .O 1 .9 9 .5 3 .0 4 . 5 3 .5 4 .0 1 .5 1 .0 5 .5 12 .5 3 .0 1 . 5  .72 .68 .64 .70 .71 .78 . 72 .76 .74 .66 .68 .69 .65 .63 . 78 . 70 .69 .78 .78 .82 . 74 .69 .82 . 72 .70 .69 .69 .71  1 05 1 03 90 1 00 1 20 1 43 1 21 1 37 1 14 1 04 1 24 1 24 1 02 1 04 1 45 1 19 1 22 1 09 1 53 1 06 1 36 1 24 1 40 1 41 1 03 87 1 18 1 31  Appendix 14c. M u l t i f a r m t r i a l : S o i l data from c o n t r o l plots  (0) a t harvest (H).  ui  YR S I T E NH4N1H1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 2  1 2 3 4 5 6 7 8 9 10 1 1 12 13 14 15 16 17 1 2 3 4 5 6 7 8 9 10 1 1  1 3 3 3 1 10 2 2 1 1 1 12 10 3 9 3 7 5 5 19 10 5 1 1 10 7 1 1  5 8 8 3 3 5 5 1 9 0 9 0 3 9 9 4 9 5 5 5 0 5 5 0 0 5 0 5  N03N1H1 DW1H1 BD1H1 NH4N2H1 2 13 1 8 2 10 6 6 12 7 4 10 7 2 10 14 14 24 9 99 23 7 5 1 1 32 23 3 2  5 5 0 0 0 3 3 7 0 2 0 2 2 1 0 2 5 5 5 8 0 0 0 5 0 5 5 5  Appendix  .76 .75 . 73 . 79 .76 . 79 .77 . 79 .75 . 76 . 74 . 72 . 78 .76 .82 . 70 . 77 . 78 . 79 . 78 .80 .75 . 76 . 78 . 79 . 75 . 77 . 76  1 .22 1 17 1 17 1 13 1 .09 .89 1 . 18 98 91 1 00 1 03 1 01 1 .03 1 .08 93 1 25 1 25 1 43 1 23 1 06 1 .42 1 17 1 12 1 26 1 30 1 25 1 27 1 15  1 9 1 1 1 2 1 1 1 1 1 1  1 1 1 1 1 1 2 1 2 1 1  5 3 0 0 9 3 4 3 1 1 3 6 7 8 7 8 6 0 0 5 5 5 0 5 0 0 0 0  14d. M u l t i f a r m Plots  N03N2H1 DW2H1 BD2H1 NH4N3H1 3 0 4 6 1 0 6 4 1 2 1 3 1 6 3 6 1 7 5 9 2 3 8 2 5 9 2 7 9 0 4 0 15 5 5 5 3 5 1 5 1 0 4 5 8 5 7 0 1 0  .71 .70 .67 . 76 .73 .80 .77 .80 .71 . 72 .73 .71 .70 .66 . 78 . 76 . 73 . 77 .82 .85 .80 . 73 .83 .75 . 78 .72 .69 . . 73  trial:  Soil  1 09 1 08 85 1 29 1 .48 1 . 29 1 42 1 35 1 31 99 1 37 1 26 1 29 1 14 1 34 90 1 46 1 47 1 46 1 30 1 39 1 41 1 81 1 60 1 19 93 1 28 1 35  data  (1) a t h a r v e s t ( H ) .  1 8 1 2 1 2 1 1 2  1 2 1 1 1 1 1 1 1 2 1 1  N03N3H1 DW3H1 BD3H1  0 5 0 7 0 7 3 7 3 3 9 8 7 7 8 7 3 0 0 5 5 0 0 0 0 0 0 0  from  2 3 3 9 9 1 0 4 1 5 1 1 5 1 8 2 4 3 3 1 8 6 2 6 9 2 3 12 5 9 0 1 5 6 0 5 0 4 0 1 0 1 0 5 5 4 0 1 0  .65 .67 .66 .68 .71 . 76 .72 .76 .73 .66 . 74 . 75 .63 .64 . 78 .70 .66 . 70 .78 .85 . 74 . 70 . 78 . 72 .70 .67 .65 . 71  1 05 1 03 90 1 00 1 20 1 43 1 21 1 37 1 14 1 04 1 24 1 24 1 02 1 04 1 45 1 19 1 22 1 09 1 53 1 06 1 36 1 24 1 40 1 41 1 03 87 1 18 1 31  fertilized  155  YR SITE 0-20 20-50 50"80 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 2  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 1 2 3 4 5 6 7 8 9 10 11  21 . 97 7 . 36 63 .36 13 . 85 4 .05 37 .71 20 .62 47 . 79 4 1. 29 19 . 20 10 .00 40 .06 25 .97 12 .68 16 .. 10 15 ,.00 43 . 33 143 ..00 62 . 28 124 . 26 108 . 29 48 . 00 92 . 88 40. 95 87 . 75 85. 44 32 . 71 30. 26  23 . 36 00 22 . 84 00 00 20. 10 00 20. 77 22 . 45 00 00 15 ..53 56. .09 15 ..09 30. .92 .00 30 .00 92 . 56 55 . 44 48 . 75 48 . 74 5 1 .45 38 . 83 37 .40 51 .67 55 .80 44 . 52 55 . 48  20. OO 00 4 .15 .00 .00 23. . 19 00 .00 4 .56 .00 .00 .00 9 .27 .00 27 .53 .00 16 . 15 78 . 30 55 .08 48 .92 53 . 22 37 . 20 33 . 16 35 . 25 49 .26 87 .00 59 .00 44 .91  0-50 45 . 33 7 . 36 86 . 20 13 .85 4 .05 57 .82 20 . 62 68 . 56 63 .74 19 .20 10 .00 55 .59 82 .06 27 . 76 47 .03 15 .00 73 . 33 235 . 56 117 . 72 173 . 01 157 ..03 99 . 45 131 . 7 1 78 . 35 139. 42 14 1. 24 77 . 23 85 . 74  Appendix 15. M u l t i f a r m t r i a l : _i  0-80 65 . 33 7 . 36 90 . 35 13 .85 4 .05 81 .01 20 .62 68 .56 68 .30 19 .20 10 .00 55 .59 91 . 33 27 . 76 . 74.. 56 15 ..00 89 .48 3 13 . 85 172 . 80 221 . 93 2 10 25 136 . 65 164 . 86 113. 60 188 . 68 228 . 24 136 . 23 130. 66  Kelowna s o i l  values (kg ha ).  nitrate  156  R SITE  STSO  STS1  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 1 2 2 2 2 3 4 2 5 2 6 2 7 2 8 2 9 2 2 10 2 1 1  19 22 19 18 22 18 16 21 19 19 19 19 19 17 22 17 19 27 20 18 17 23 20 19 17 20 21 37  18 18 14 16 21 23 18 19 19 18 24 19 20 16 20 19 20 37 20 19 20 20 18 18 20 20 21 34  STWO  STW1  26 40 22 25 20 30 19 40 43 16 34 37 29 26 21 14 39 38 28 53 29 31 37 29 23 33 32 33  33 40 24 32 27 30 18 33 45 19 40 37 34 29 20 25 38 49 29 57 34 32 39 35 26 40 32 35  56 39 68 44 46 98 37 39 15 05 29 61 32 56 59 93 05 17 21 10 87 53 06 .87 .79 .74 .53 .85  73 93 34 07 65 41 80 20 90 90 39 05 29 32 46 44 20 79 87 53 30 08 83 40 .00 .93 .42 . 18  STDO 5 6 3 4 3 5 4 8 6 2 4 6 4 5 4 3 7 7 4 6 5 4 5 3 4 3 5 5  58 46 86 32 88 89 07 48 47 89 80 02 69 05 53 28 03 63 51 90 08 73 93 88 .28 .71 . 14 . 15  STD1 6 7 3 5 4 5 3 5 6 3 6 5 5 6 5 5 6 8 4 8 4 4 5 4 4 5 5 5  41 37 89 77 43 47 01 98 89 78 46 93 83 45 12 60 65 46 78 05 80 81 58 60 .68 32 32 .35  STDMO  STDM1  STNO  STN1  TODO  T0D1  .21 . 16 . 17 . 17 . 19 . 19 .21 .21 . 15 . 18 . 14 . 16 . 16 . 19 .21 . 18 . 18 .20 . 16 . 13 . 17 . 15 . 16 . 13 . 18 . 11 . 16 . 15  . 19 . 18 . 16 . 18 . 16 . 18 . 16 . 18 . 15 . 19 . 16 . 16 . 17 .22 .25 .21 . 17 . 17 . 16 . 14 . 14 . 15 . 14 . 13 . 18 . 13 . 16 . 15  .51 1 . 16 1 . 18 .85 .54 .79 .90 1 .03 1 . 12 .77 .83 .89 81 52 1 .31 1 24 1 00 1 02 1 35 1 44 1 11 1 16 1 19 1 36 1 07 1 27 90 99  1 .21 1 .03 .82 .84 .90 .88 1 .07 .94 1 .20 .89 1 .22 1 02 81 77 1 .40 1 04 1 18 1 50 1 34 1 38 1 50 1 10 1 34 1 57 1 28 1 20 1 10 88  1 .22 1 .90 .83 .63 .49 1 .85 .78 2 .68 1 46 1 32 1 17 2 44 2 34 2 10 1 07 24 87 1 55 87 1 74 1 29 78 1 20 1 06 1 05 1 03 1 22 65  2 .00 2 .20 1 .80 .73 .83 1 .85 .59 1 .85 1 27 2 05 1 51 2 34 2 29 68 1 17 88 95 1 68 1 05 2 02 1 42 1 17 1 64 1 72 82 1 14 1 25 1 39  YR = Y e a r (1=1984, 2=1985) S I T E = S i t e (1-17 i n 1984, 1-11  i n 1985) •  0 = Control plot 1 = Fertilized plot STS = Number o f s t a l k s _. STW = S t a l k y i e l d , f r e s h ( t h a ~ ) STD = S t a l k y i e l d , f r e s h ( t h a " ) STDM = S t a l k d r y m a t t e r ( p r o p o r t i o n o f STN = S t a l k n i t r o g e n (%) _ TOD = T o p y i e l d , d r y ( t h a ) 1  Appendix  16a. M u l t i f a r m  trial:  Com  data.  fresh)  157  YR S I T E 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 2  1 2 3 4 5 6 7 8 9 10 1 1 12 13 14 15 16 17 1 2 3 4 5 6 7 8 9 10 1 1  COSO 24 24 17 22 21 26 15 30 20 20 24 26 20 18 26 20 27 25 25 32 23 32 32 20 24 24 25 24  COS1 COWO 24 21 18 28 23 28 22 26 21 19 29 26 23 25 29 23 26 31 31 32 30 30 30 28 28 33 25 28  19. 63 21 . 56 12 . 17 18. 24 1 1 . 07 2 0 . 20 10. 51 24 . 60 18. 80 1 1 .61 17. 71 21 ..59 14.. 10 14 ,. 10 21 .29 19. . 9 0 23 .92 29 .32 21 . 8 5 31 . 2 5 24 . 3 4 23 .23 26 . 5 5 12 . 4 5 23 .01 23 . 7 9 26 .61 18 .31  COW1  CODO  C0D1  21 . 56 18. 54 12. 73 26. 00 17 . 15 2 2 . 68 14 . 66 21 . 85 2 0 . 46 16. 59 2 2 . ,41 2 2 . 95 21 ..85 19 .63 2 2 , .41 19. .37 24,. 0 0 28 .21 26 . 5 5 30 . 9 8 26 . 5 5 25 . 6 7 28 .21 24 . 8 9 25 . 78 29 . 3 2 27 .71 20 . 19  5 . 69 5 . 17 2 . 80 4 . 74 2 . 77 5 . 45 2 . 73 6 . 40 6 . 39 3. 83 4 . 25 5. 18 3..81 3 .53 5,.75 5,.37 5,.55 7 .33 5 .03 7 .50 4 .87 5 . 11 5 .58 2 .49 5 .75 4 .04 5 .80 3 .74  6 . 47 4 . 82 2 . 29 5 . 98 4 . 12 6 . 12 3 . 66 5 . 68 4 . 91 4 . 48 4 . 71 6. .43 5, . 9 0 5, . 10 5, .38 5. .81 5 .33 6 .77 5 .04 6 .82 5 .58 4 .62 6 .21 4 .73 5 . 16 5 .86 6 . 10 4 .04  CODMO  C00M1  CONO  C0N1  TISO  TIS1  .29 . 24 .23 .26 .25 .27 .26 . 26 .34 .33 .24 .24 .27 .25 .27 .27 .23 .25 .23 .24 .20 .22 .21 .20 .25 . 17 .22 .20  .30 .26 . 18 .23 .24 .27 .25 .26 .24 .27 .21 .28 .27 .26 .24 .30 .22 .24 . 19 .22 .21 . 18 .22 . 19 .20 .20 .22 .20  1 . 10 1 .35 1 .43 1 .24 1 .25 1 . 19 1 .54 1 . 19 1 . 18 1 .21 1 . 19 1 .32 1 .22 1 . 12 1 .35 1 .40 1 .02 1 .40 1 .67 1 .57 1 .55 1 .40 1 .37 1 .62 1 .28 1 .62 1 .29 1 .35  1 .38 1 .65 1 .40 1 .30 1 .44 1 .29 1 . 19 1 .28 1 . 18 1 .37 1 .49 1 . 17 1 .25 1 . 19 1 .37 1 .96 1 . 19 1 .78 1 .68 1 .50 1 .75 1 .57 1 .40 1 .62 1 .50 1 .64 1 .38 1 .52  20 24 12 28 14 24 1 1 31 16 4 21 17 6 25 22 8 28 44 29 34 17 30 29 21 34 17 33 28  26 33 16 23 13 21 10 16 17 6 13 24 13 27 12 12 26 53 24 31 26 32 31 26 28 28 32 21  YR = Year (1=1984, 2=1985) SITE = S i t e (1-17 i n 1984, 1-11 i n 1985) 0 = Control plot 1 = Fertilized plot COS = Number o f cobs . COW = Cob y i e l d , f r e s h ( t ha ) COD = Cob y i e l d , d r y ( t ha ) CODM = Cob d r y matter ( p r o p o r t i o n o f f r e s h ) CON = Cob n i t r o g e n (%) TIS = Number o f t i l l e r s  Appendix 16b. M u l t i f a r m  t r i a l : C o m data.  158  YR SITE 1 1 1 1  1  1 2 3 4 5 6  1 1 7 1 8 1 9 1 10 1 1 1  1 12 1 13 1 14 1 15 1 16 1 17 2 1 2 2 2 2 2 2 2 2 2 2  2 3  4 5  6 7 8  9  10 1 1  STNODW  STNIDW  34 95 96 8 1 55 58 42 32 23 82 6 1 38 43 84 1 15 5 1 88 50 32 42 49 6 1 75 04 57 08 37 54 73 36 43 54 78 68 94 09 72 68 124 50 70 58 63 97 84 70 67 18 56 87 60 20 57 05 57 65  101 99 46 54 47 64 38 73 98 51 97 84 65 55 88 67 89 152 78 139 93 65 96 98 70 77 72 59  CONODW  . 5 1 62 69 05 40 77 58 53 34 55 7 1 64 41 66 76 45 75 00 46 83 50 31 68 77 46 93 39 26 77 06 75 20 56 53 10 102 83 12 17 117 75 1 1 71 73 76 75 40 97 73 45 65 26 74 01 50 33  82 85 18 63 76 85 99 35 27 42 57 43 56 64 74 23 61 62 85 52 48 54 28 26 77 45 65 38  C O N 1DW  RSTW  RSTD  RCOW  RCOD  89 6 1 79 58 32 1 1 77 98 53 20 78 95 43 63 72 48 57 89 6 1 47 69 99 75 42 74 04 60 64 73 65 1 13 64 63 59 120 7 1 84 82 102 30 97 65 72 67 86 94 76 48 77 50 96 05 83 94 6 1 37  . 79 .99 93 . 79 74 1 02 1 03 1 22 94 81 85 1 02 86 91 1 06 59 1 02 77 94 92 87 98 93 84 91 . 82 1 .OO . 96  .87 . 88 .99 .75 .88 1 .08 1 . 35 1.42 .94 . 76 .74 1 .02 .80 .78 . 88 .59 1 .06 . 90 .94 . 86 1 .06 .98 1 .06 .84 .91 .70 . 97 .96  .91 1 . 16 .96 . 70 .65 .89 . 72 1.13 .92 .70 .79 .94 .65 .72 .95 1 .03 1 .00 1 .04 . 82 1.01 . 92 .90 .94 . 50 . 89 .81 .96 .91  .88 1 07 1 22 79 67 89 75 1 13 1 30 85 90 81 65 69 1 07 92 1 04 1 08 1 00 1 10 87 1. 1 1 .90 .53 1. 1 1 .69 . 95 .93  RYIELDW  . 84 1 .04 .94 .75 .70 . 96 .89 1 . 18 . 93 . 76 .33 .99 . 77 .83 1 OO 78 1 01 87 89 95 89 95 93 70 90 82 98 94  RYIELDD  . 84 .94 . 94 . 78 . 76 . 98 1 .04 1 . 30 1 . 10 . 78 .8 1 .93 . 77 .87 . 97 .72 1 .04 .98 .96 . 96 . 95 1 .00 . 95 . 67 1 .04 .71 . 96 .88  YR = Year (1=1984, 2=1985) SITE = S i t e (1-17 i n 1984, 1-11 i n 1985) 0 = Control plot 1 = Fertilized plot -1 STNODW = S t a l k n i t r o g e n (kg ha_.| ) C o n t r o l p l o t (0) STN1DW = S t a l k n i t r o g e n (kg ha ) CONODW = Cob n i t r o g e n (kg ha ) RSTW = R e l a t i v e y i e l d , s t a l k s f r e s h RSTD = R e l a t i v e y i e l d , s t a l k s d r y RCOW = R e l a t i v e y i e l d , cobs f r e s h RCOD = R e l a t i v e y i e l d , cobs d r y RYIELDW = R e l a t i v e y i e l d , whole p l a n t f r e s h RYIELDD = R e l a t i v e y i e l d , whole p l a n t d r y  Appendix  16c.  M u l t i f a r m t r i a l : Corn d a t a .  159  YR S I T E t 1 1 t t 1 1  !  1  1  1 2 2 2 2 2 2 2 2 2 2 2  1 2 3 4 5 6 7 S 9 10 11 12 13 14 15 16 17 1 2 3 4 5 6 7 8 9 10 1 1  CORNWO 46 61 34 43 31 51 29 64 6 1 27 52 59 43 40 42 34 62 67 50 84 54 54 63 42 46 57 59 52  19 95 85 68 53 18 88 99 95 66 00 20 42 66 88 83 97 49 06 35 2 1 76 61 32 80 53 14 16  C0RNW1 55 59 37 58 44 53 33 55 66 3G 62 60 56 48 42 44 62 78 56 88 60 57 68 60 51 70 60 55  29 47 07 07 80 09 46 05 36 49 80 00 14 95 87 81 20 OO 42 51 85 75 04 29 78 25 13 37  CORNOO 12 13 7 9 7 13 7 17 14 8 10 13 10 10 1 1 8 13 16 10 16 1 1 10 12 7 1 1 8 12 9  49 53 49 69 14 19 58 56 32 04 22 64 84 88 35 89 45 51 41 14 24 62 7 1 43 08 78 16 54  C0RND1 14 14 7 12 9 13 7 13 13 10 12 14 14 12 1 1 12 12 16 10 16 1 1 10 13 1 1 10 12 12 10  88 39 98 48 38 44 26 5 1 07 31 68 70 02 23 67 29 93 91 87 89 80 60 43 05 66 32 67 78  CORNO 8 1 1 25 1 31 1 05 90 99 1 22 1 1 1 1 15 99 1 01 1 10 1 02 82 1 33 1 32 1 01 1 21 1 51 1 .50 1 . 33 1 28 1 28 1 . 49 1 17 1 44 1 09 1 . 17  CORNNO 97 166 95 100 58 126 85 191 163 78 100 143 103 77 151 1 18 135 196 156 242 146 135 160 107 130 125 13 1 108  C0RNN1  77 66 76 96 58 23 83 86 77 84 19 47 64 18 10 78 29 7 1 53 03 06 51 98 45 64 65 70 03  19 1 . 12 178 63 78 88 132 5 1 106 75 143 66 82 29 145 92 155 89 1 13 29 167 30 160 19 139 98 1 15 90 16 1 7 1 180 84 153 1 1 272 8 1 162 95 24 1 47 190 76 138 45 183 69 175 46 147 96 173 31 155 94 120 75  YR = Year (1=1984, 2=1985) SITE = S i t e (1-17 i n 1984, 1-11 i n 1985) 0 = Control p l o t 1 = Fertilized plot CORNW = Whole p l a n t y i e l d , f r e s h ( t ha ) CORND = Whole p l a n t y i e l d , d r y ( t ha ) CORN = Whole p l a n t n i t r o g e n (%) __ CORNN = Whole p l a n t n i t r o g e n (kg ha ) 1  1  Appendix  16d. M u l t i f a r m  t r i a l : Corn d a t a .  

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