UBC Theses and Dissertations

UBC Theses Logo

UBC Theses and Dissertations

Phosphorus availability in two calcareous soils Gough, Neville Astor 1961

Your browser doesn't seem to have a PDF viewer, please download the PDF to view this item.

Item Metadata

Download

Media
831-UBC_1961_A4 G6 P4.pdf [ 4.59MB ]
Metadata
JSON: 831-1.0105853.json
JSON-LD: 831-1.0105853-ld.json
RDF/XML (Pretty): 831-1.0105853-rdf.xml
RDF/JSON: 831-1.0105853-rdf.json
Turtle: 831-1.0105853-turtle.txt
N-Triples: 831-1.0105853-rdf-ntriples.txt
Original Record: 831-1.0105853-source.json
Full Text
831-1.0105853-fulltext.txt
Citation
831-1.0105853.ris

Full Text

PHOSPHORUS AVAILABILITY IN TWO CALCAREOUS SOILS by  NEVILLE ASTOR GOUGH .S.A., The University of B r i t i s h Columbia, 1959  A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE IN AGRICULTURE  in the Department of SOIL SCIENCE  We accept this thesis as conforming to the required standard  THE UNIVERSITY OF BRITISH COLUMBIA July, 1961  In p r e s e n t i n g  t h i s thesis i n p a r t i a l fulfilment of  the r e q u i r e m e n t s f o r an advanced degree a t t h e British  Columbia, I agree t h a t the  a v a i l a b l e f o r reference  and  study.  University  of  L i b r a r y s h a l l make i t f r e e l y • I f u r t h e r agree t h a t  permission  f o r e x t e n s i v e copying o f t h i s t h e s i s f o r s c h o l a r l y purposes may g r a n t e d by  the  Head o f my  It i s understood t h a t f i n a n c i a l gain  Department  representatives.  copying or p u b l i c a t i o n of t h i s t h e s i s f o r  s h a l l not  be a l l o w e d w i t h o u t my  of  The U n i v e r s i t y o f B r i t i s h Vancouver 8, Canada. Date  Department o r by h i s  be  Columbia,  written  permission.  ii  ABSTRACT A study was made of the influence of s o i l moisture tension and s o i l temperature on the a v a i l a b i l i t y of phosphorus from f i v e d i f f e r e n t compounds i n two calcareous s o i l s . In the study of moisture tension, the top six inches of Machete stony sandy loam and of N i s c o n l i t h clay loam were treated with f i v e phosphate c a r r i e r s of varying water s o l u b i l i t y , monoammonium phosphate, monocalcium phosphate, anhydrous dicalcium phosphate, calcium metaphosphate and hydroxyapatite, at a rate equivalent to 120 pounds of P 0 per acre. 2 5 The s o i l s were placed i n empty crocks and weighed.  These weights were  used along with information obtained from previously prepared moisture tension curves to maintain the moisture tension ranges.  The tension  ranges used were: 0.2 - 0.4, 0.2 - 0.8, 0.2 - 2.0 and 0.2 - 6.0 bars. Irrometers were used to measure and control moisture tension ranges of 0.2 - 0.4 and 0.2 - 0.8 bars.  The moisture tension ranges of 0.2 - 2.0  and 0.2 - 6.0 bars were measured gravimetrically.  The s o i l s were seeded  with a l f a l f a and placed i n growth chambers b u i l t i n the greenhouse. Three cuttings of the plants were made at the t h i r d blossom stage and the dried plant tissue was analysed for phosphorus.  At the end of the  f i r s t cutting^ NaHCO-j extractable phosphorus was determined i n these s o i l s and dicalcium phosphate a c t i v i t y at the end of the t h i r d harvest. S t a t i s t i c a l methods were used to determine the significance of the experimental r e s u l t s . The y i e l d s from both s o i l s showed that a moisture tension range of 0.2 - 2.0 bars gave the best growth for the tensions. On the N i s c o n l i t h s o i l s the other tensions gave y i e l d s that were almost as high as those obtained at 0.2 - 2.0 bars tension.  This moisture tension was also the  iii  most favourable for phosphorus uptake as indicated by the phosphorus content i n plant t i s s u e . The e f f e c t of phosphorus source proved to be of no s i g n i f i cance on the y i e l d of a l f a l f a . The phosphorus content i n plant tissue from the Machete s o i l was related to the degree of water s o l u b i l i t y of the phosphate compounds.  A s i g n i f i c a n t difference between the effectiveness of the  water soluble compounds, such as monoammonium phosphate and the water insoluble or c i t r a t e insoluble compounds such as hydroxyapatite, was observed.  S o i l moisture tension had a s i g n i f i c a n t e f f e c t on the phosphorus  content i n plant tissue at a 10% p r o b a b i l i t y . NaHCQ-j extractable phosphorus, removed from both s o i l s a f t e r the f i r s t cutting, was not d i r e c t l y related to the degree of water soluble phosphorus content of the compounds added.  On the Machete s o i l ,  monocalcium phosphate treated s o i l released the greatest amount of NaRGO^ extractable phosphorus, yet the monoammonium phosphate i s ten times more soluble i n water.  Moisture tension had no e f f e c t on the amount of NaHCO^  extractable phosphorus released. Dicalcium phosphate a c t i v i t y calculated from the calcium, magnesium and phosphorus concentrations i n the s o i l solutions proved to be unsuitable for predicting the a v a i l a b i l i t y of phosphorus from the phosphate compounds.  These determinations might have proved otherwise i f  the f e r t i l i z e r t r i a l s were of a shorter duration. o In the study of the effects of two s o i l temperatures 10 C and 24°C, on phosphorus a v a i l a b i l i t y , the same two s o i l s , Machete stony sandy loam and N i s c o n l i t h clay loam were used.  The two s o i l s were potted and  f i v e phosphate compounds added at a rate equivalent to 120 pounds of P ° 5 2  per acre.  These pots were seeded with a l f a l f a and subjected to s o i l  /  iv o  o  temperatures of 10 C and 24 C.  The f i r s t temperature was maintained  by the use of a temperature bath placed i n the greenhouse and the second temperature was maintained by placing the pots on the greenhouse bench. I t was found that at the higher temperature of 24°C higher y i e l d s of a l f a l f a were obtained than at 10°C.  No one phosphate source  was outstanding i n i t s effect on a l f a l f a y i e l d from both s o i l s . There was a trend towards increased NaHCO^ extractable phosphorus with an increase i n temperature i n both s o i l s .  V  TABLE OF CONTENTS Page 1. INTRODUCTION  -  2. LITERATURE REVIEW  -  -  3. EXPERIMENTAL  1 -  3  -  9  1. 2.  Materials A n a l y t i c a l Methods (a) Determination of s o i l moisture tension curve (b) Determination of Phosphorus i n plant tissue (c) Determination of NaHCO^ extractable phosphorus — (d) Determination of Calcium, Calcium plus Magnesium and phosphorus i n the s o i l extracts (e) Determination of C0 p a r t i a l pressure (f) Determination of pH 3. ' Calculation of Ion A c t i v i t i e s (a) Calculation of H P0" a c t i v i t y --(b) Calculation of HPOr a c t i v i t y (c) Calculation of Ca++ a c t i v i t y (d) Calculation of dicalcium phosphate a c t i v i t y 2  2  Part I 1.  2.  9 12 12 12 12 14 14 14 15 15 16 16 16  INFLUENCE OF SOIL MOISTURE TENSION ON THE YIELD AND UPTAKE OF PHOSPHORUS BY ALFALFA  Methods and Design (a) C o l l e c t i o n and treatment of s o i l s (b) Experimental design (c) F e r t i l i s a t i o n (d) Potting and i r r i g a t i o n (e) Seeding (f) Harvesting (g) Treatment of s o i l solutions Results and Discussion (a) Y i e l d (b) Phosphorus content (c) Uptake of phosphorus (d) NaHCO extractable phosphorus (e) Dicalcium phosphate a c t i v i t i e s  ---  17 17 17 17 17 18 18 18 24 24 32 38 44 49  vi  Part I I  EFFECT OF TEMPERATURE ON THE YIELD AND UPTAKE OF PHOSPHORUS BY ALFALFA  Page  1.  Methods and Design (a) Experimental design (b) F e r t i l i s a t i o n (c) Potting and i r r i g a t i o n (d) Maintenance of temperature (e) Seeding and harvesting (f) Treatment of s o i l solutions  51 51 51 51 51 52 52  2.  Results and Discussion (a) Y i e l d (b) Phosphorus content (c) Uptake of phosphorus (d) NaHCO^ extractable phosphorus  55 55 56 66 67  4.  SUMMARY AND CONCLUSION  70  5.  APPENDICES  73  6.  BIBLIOGRAPHY  -  95  vii LIST GF TABLES Page Table 1.  Some properties of surface (0-6 inches) of the Machete stony sandy loam and the N i s c o n l i t h clay loam  20  Table 2.  Nature of phosphate compounds used i n experiments  21  Table 3.  Water s o l u b i l i t y of the f e r t i l i z e r s at various temperatures Y i e l d of a l f a l f a at four moisture tension ranges i n Machete stony sandy loam treated with phosphate c a r r i e r s of d i f f e r e n t water s o l u b i l i t y  Table 4.  Table 5.  Table 6.  21  22  Y i e l d of a l f a l f a at four moisture tension ranges i n N i s c o n l i t h clay loam treated with phosphate c a r r i e r s of d i f f e r e n t water s o l u b i l i t y  23  Phosphorus content i n a l f a l f a at four moisture tension ranges i n Machete stony sandy loam treated with phosphate c a r r i e r s of d i f f e r e n t water s o l u b i l i t y  30  Table 7.  Phosphorus content i n a l f a l f a at four moisture tension ranges i n N i s c o n l i t h clay loam treated with phosphate c a r r i e r s of d i f f e r e n t water s o l u b i l i t y 31  Table 8.  Phosphorus uptake by a l f a l f a at four moisture tension ranges in Machete stony sandy loam treated with phosphate c a r r i e r s of d i f f e r e n t water s o l u b i l i t y 36  Table 9 .  Phosphorus uptake by a l f a l f a at four moisture tension ranges in N i s c o n l i t h clay loam treated with phosphate c a r r i e r s of d i f f e r e n t water s o l u b i l i t y 37  Table 10. NaHC© extractable phosphorus remaining i n the Machete stony sandy loam at the end of the 1st a l f a l f a cutting -  42  Table 11. NaHCO-j extractable phosphorus remaining i n the N i s c o n l i t h clay loam at the end of the 1st a l f a l f a cutting  43  Table 12. Dicalcium phosphate a c t i v i t i e s i n Machete stony sandy loam calculated using Ca, Mg, and P concentrations i n the s o i l solutions  47  Table 13. Dicalcium phosphate a c t i v i t i e s i n N i s c o n l i t h clay loam calculated using Ca, Mg and P concentrations i n the s o i l solutions  48  3  viii Table 14. Y i e l d of a l f a l f a at two s o i l temperatures 10 G and 24°C i n Machete stony sandy loam treated with phosphate c a r r i e r s of d i f f e r e n t water s o l u b i l i t y  Page  53  o o Table 15. Y i e l d of a l f a l f a at two s o i l temperatures, 10 C and 24 C i n N i s c o n l i t h clay loam treated with phosphate c a r r i e r s of d i f f e r e n t water s o l u b i l i t y  54  Table 16. Phosphorus gontent i n a l f a l f a at two s o i l temperatures 10°C and 24 C i n Machete stony sandy loam treated with f i v e phosphate c a r r i e r s of d i f f e r e n t water solubility  58  Table 17. Phgsphorus gontent i n a l f a l f a at two s o i l temperatures, 10 C and 24 C i n N i s c o n l i t h clay loam treated with f i v e phosphate c a r r i e r s of d i f f e r e n t water s o l u b i l i t y  59  Table 18. Phgsphorus uptake by a l f a l f a at two s o i l temperatures, 10 G and 24°C i n Machete stony sandy loam treated with f i v e phosphate c a r r i e r s of d i f f e r e n t water s o l u b i l i t y  61  Table 19. Phgsphorus yptake by a l f a l f a at two s o i l temperatures, 10 C and 24 C, i n N i s c o n l i t h clay loam treated with f i v e phosphate c a r r i e r s of d i f f e r e n t water s o l u b i l i t y  62  Table 20. NaHCO-j extractable phosphorus remaining i n the Machete stony sandy loam at the end of the 1st cutting  64  Table 21. NaHC0_ extractable phosphorus remaining i n the N i s c o n l i t h clay loam at the end of the 1st a l f a l f a cutting  65  ix  LIST OF FIGURES Page  Figure 1. Moisture tension curves showing the relationship between s o i l moisture tension and the weight of water held on Machete stony sandy loam and N i s c o n l i t h clay loam s o i l s  13  Figure 2. The e f f e c t of s o i l moisture tensions and phosphate f e r t i l i z e r s on the y i e l d of a l f a l f a grown on the Machete stony sandy loam  28  Figure 3. The e f f e c t of s o i l moisture tensions and phosphate f e r t i l i z e r s on the y i e l d of a l f a l f a grown on the N i s c o n l i t h clay loam  29  Figure 4. The e f f e c t of s o i l moisture tension and phosphate f e r t i l i z e r s on the per-cent of phosphorus i n a l f a l f a tissue on Machete stony sandy loam  34  Figure 5. The e f f e c t of s o i l moisture tension and phosphate f e r t i l i z e r s on the per-cent phosphate i n a l f a l f a tissue on the N i s c o n l i t h clay loam  35  Figure 6. The effect of s o i l moisture tension and phosphate f e r t i l i z e r s on the y i e l d of phosphorus on the Machete stony sandy loam  40  Figure 7. The effect of s o i l moisutre tension and phosphate f e r t i l i z e r s on the y i e l d of phosphorus on the N i s c o n l i t h clay loam  41  Figure 8. The e f f e c t of s o i l moisture tension and phosphate f e r t i l i z e r s on NaHC0„ extractable phosphorus on the Machete stony sandy loam  45  Figure 9. The e f f e c t of s o i l moisture tension and phosphate f e r t i l i z e r s on NaHC0_ extractable phosphorus on the N i s c o n l i t h clay loam  46  Figure 10. The e f f e c t of s o i l temperatures and phosphate f e r t i l i z e r s on the y i e l d of a l f a l f a grown on the Machete stony sandy loam and the N i s c o n l i t h clay loam -  57  X  Page Figure 11. The e f f e c t of s o i l temperatures and phosphate f e r t i l i z e r s on the per-cent phosphorus i n a l f a l f a tissue on the Machete stony sandy loam and the N i s c o n l i t h clay loam  60  Figure 12. The effect of s o i l temperatures and phosphate f e r t i l i z e r s on the uptake of phosphorus on the Machete stony sandy loam and the N i s c o n l i t h clay loam  63  Figure 13. The e f f e c t of s o i l temperatures and phosphate f e r t i l i z e r s on NaHCO^ extractable phosphorus from the Machete stony sandy loam and the . N i s c o n l i t h clay loam  68  xi  ACKNOWLEDGEMENTS The author wishes to express his indebtedness to Dr. J . D. Beaton, Canada Department of Agriculture, Swift Current, Saskatchewan,  for h i s guidance and i n s t r u c t i o n  during the course of  this study. He i s p a r t i c u l a r l y grateful to Dr. C. A. Rowles, Chairman of the Department of S o i l Science, University of B r i t i s h Columbia and to Dr. J . S. Basaraba for t h e i r interest and suggestions from time to time. For t h e i r help i n s t a t i s t i c a l analysis of the experiments, the author wishes to thank Drs. S. W. Nash and D. P. Ormrod, and also Mr. St. C. Forde for his p r a c t i c a l help and c r i t i c i s m s .  The author acknowledges  the f i n a n c i a l assistance received  from the Canada Department of Agriculture through Extra Mural Research Grant 107 and the National Research Council annual grant A727.  1 INTRODUCTION The importance of phosphorus as a major plant nutrient has been known for many years.  However, the problem of providing plants with  adequate amounts of phosphorus from s o i l s for any great length of time s t i l l exists.  In many s o i l s the t o t a l quantity of phosphorus present  may be high, but very l i t t l e of this i s available for plant use.  This  i s due to the fact that the phosphorus i s fixed, e x i s t i n g i n the forms of insoluble basic calcium phosphates i n a l k a l i n e and neutral s o i l s and i n a c i d s o i l s as phosphates of aluminum and i r o n .  To s o i l s where  the available phosphorus i s low, phosphorus f e r t i l i z e r s may be added. Of the many phosphate compounds which constitute chemical f e r t i l i z e r s , the calcium phosphates and ammonium phosphates are becoming increasingly popular.  These compounds vary widely i n composition and  water s o l u b i l i t y . The s o l u b i l i t y of the basic calcium phosphates have been studied extensively i n calcareous  soils.  I t i s known that the s o l u b i l i t y  of the calcium phosphates i s a function of pH and Ca++ a c t i v i t y , with a minimum s o l u b i l i t y between pH 7.0 - 7.5 and an increase i n s o l u b i l i t y on either side of pH 7.0. On the a l k a l i n e side, the s o l u b i l i t y of phosphorus, i n the presence of s o l i d phase CaCO^, i s a function of the Ca++ a c t i v i t y , whereas on the acid side of pH 7.0 - 7.5, the s o l u b i l i t y of phosphorus i s a function of both the H+ a c t i v i t y and the Ca-H- a c t i v i t y .  An increase  in the H+ a c t i v i t y increases phosphorus s o l u b i l i t y , and an increase i n Ca ++ a c t i v i t y decreases the s o l u b i l i t y of phosphorus. I t i s recognised  that the calcium phosphates vary i n their  water s o l u b i l i t i e s and importance as major constituents of many f e r t i l i z e r s . As a r e s u l t , a study was made to examine the e f f e c t of d i f f e r e n t levels of moisture tension on y i e l d and phosphorus uptake by a l f a l f a .  I t was also  2  believed that information on the a v a i l a b i l i t y of phosphorus i n calcareous s o i l s would be increased i f temperature effects on the calcium phosphate i n s o i l s vere studied.  Since phosphate f e r t i l i z e r s were frequently used  to increase y i e l d s on i n t e r i o r B r i t i s h Columbia s o i l s , two such s o i l s , viz:  Machete stony sandy loam and N i s c o n l i t h clay loam were chosen f o r  these investigations.  3  LITERATURE REVIEW  P r i o r to 1951 i n North America^ordinary or normal superphosphate was the phosphate f e r t i l i z e r manufactured and used i n largest quantity (34). Since that time, however, there has been a change i n the nature of the phosphate f e r t i l i z e r compounds manufactured and used (55) and H i l l (19) reports that the materials used i n largest quantities over the past f i v e years are as follows: Ammonium phosphates (mono and dibasic) - greater than 1/3 Dicalcium phosphate  - about  1/3  Monocalcium phosphate i n superphosphate- about  1/5  C i t r a t e - i n s o l u b l e phosphorus  2/15  - about  During the past several years considerable interest has been shown i n other phosphate compounds which do not appear i n H i l l ' s report. Calcium metaphosphate i s one of these. have several important advantages. (62% 2 ® 5 ^ ' * > P  a  so  kas * t  ie  As a f e r t i l i z e r material i t would  I t has a very high phosphate content  property of gradual dissolution and  hydrolysis and therefore might be superior to water soluble compounds in supplying phosphorus to crops (55). One of the most important considerations i n the selection and s u i t a b i l i t y of phosphorus f e r t i l i z e r compounds i s the r e l a t i v e a v a i l a b i l i t y to plants of the phosphorus they contain.  Many studies have been  carried out to evaluate the a v a i l a b i l i t y of phosphorus i n many compounds. Recently a very complete review of phosphate a v a i l a b i l i t y was provided by Pierre and Norman i n a 491 page monograph e n t i t l e d 'Soil and F e r t i l i z e r Phosphorus' (45). In view of t h i s , the material on the subject which follows w i l l stress the more recent publications on the subject.  4 Webb et a l (63) evaluated thirteen phosphate sources of varying water s o l u b i l i t y for their use as s t a r t e r f e r t i l i z e r s of corn.  Their  studies showed that increasing the water s o l u b i l i t y of the phosphorus resulted i n an increased early season plant growth and f e r t i l i z e r phosphorus absorption.  The e f f e c t of s a l t concentrations  on the a v a i l a b i l i t y  of phosphorus from rock phosphate was investigated by Howe et a l (20).  Seatz  e t a l (52) investigated the influence of organic matter additions on rock phosphate a v a i l a b i l i t y .  From t h e i r r e s u l t s , they attributed the increased  y i e l d s to the phosphorus i n the organic matter rather than to the b e n e f i c i a l e f f e c t of the organic matter on the a v a i l a b i l i t y of rock phosphate. The a v a i l a b i l i t y of concentrated  superphosphate as affected by  associated s a l t s , was studied by Bouldin et a l .  (4) They found that  the e f f e c t of the associated s a l t s on the a v a i l a b i l i t y of the concentrated superphosphate was l a r g e l y explained on the basis of measured chemical differences.  Terman et a l (58) determined the r e l a t i v e a v a i l a b i l i t y  of s i x well-characterized calcium phosphates to plants grown on s o i l s of varying pH. From t h e i r r e s u l t s , they concluded that monocalcium phosphate was s l i g h t l y more available than the dicalcium phosphates on the a l k a l i n e s o i l s but was less available on the a c i d s o i l s .  Hydroxyapa-  t i t e was also of very low a v a i l a b i l i t y on a l l s o i l s . Bouldin et a l (5) investigated the r e l a t i v e values of several phosphates as sources of nutrient phosphorus i n the laboratory and agronomically.  On analyzing the s o i l i n the immediate v i c i n i t y of the  f e r t i l i z e r , the measurements of water-soluble  phosphorus explained 65% of  the v a r i a t i o n i n plant uptake of phosphorus with the different f e r t i l i z e r s i n greenhouse experiments.  In a study of crop response to phosphate  f e r t i l i z e r s , as influenced by the l e v e l of phosphorus s o l u b i l i t y and by the time of placement p r i o r to planting, Norland et a l . (39) used  5 several n i t r i c phosphates, calcium metaphosphate phosphate.  and monoammonium  He obtained results which showed that delayed seeding  after f e r t i l i z a t i o n  made very l i t t l e difference at the f i r s t harvest  on the one s o i l of low phosphate-fixing capacity, while preplanting applications of the more soluble phosphates d e f i n i t e l y reduced their effectiveness on the other s o i l of high-phosphate f i x i n g capacity. Of the many factors that influence the s o l u b i l i t y of phosphate f e r t i l i z e r s and the subsequent a v a i l a b i l i t y of phosphorus to plants, granule size seems to be of some, but limited, importance. According to Terman et a l . (59), working with ammoniated superphosphates and dicalcium phosphate, granule size was of l i t t l e importance when superphosphate was banded.  When both superphosphate and dicalcium  phosphate were mixed throughout the s o i l s , then granule size greatly influenced y i e l d s on most s o i l s .  Beaton and Nielsen (2) studied the  a v a i l a b i l i t y of phosphorus from f i v e commercial f e r t i l i z e r s phosphate compounds.  and seven  In this work, the s o i l moisture tension was kept  constant within a c e r t a i n range.  Fertilizer  materials containing mono-  calcium phosphate or compounds, which eventually reverted to monocalcium phosphate, gave the greatest increases i n y i e l d . The e f f e c t of moisture has been studied by Simpson (53) who found that potatoes doubled their phosphorus uptake even a f t e r s i x weeks of growth when the s o i l moisture content was increased by i r r i g a t i o n .  He  also found (54) that lowering of s o i l moisture to f i e l d capacity greatly increased the uptake of f e r t i l i z e r phosphorus from superphosphate by oats. Collis-George and Davey (11) i n a review on the doubtful u t i l i t y of present day f i e l d experimentation remarks that the uptake of phosphorus i s known to be dependent upon s o i l moisture content. Similar and related contributions were made by Thurlow et a l  11) (62) Lathwell et a l (27) Lindsay et al,(32) and Cooke et a l (12). The quest for information as to how  the calcium phosphates  act in s o i l s has brought about experimentation without the presence of plants and sometimes outside the s o i l medium.  Clark et a l (7), i n t h e i r  work, presented a useful s o l u b i l i t y diagram from which the presence of stsble calcium phosphates i n s o i l s could be predicted i f values of pH^PO^ and pH - 1/2 pCa were known.  From this work, they inferred that hydrox-  yapatite was probably the s o l i d phase i n neutral and a l k a l i n e s o i l s . Moreno (36), using d i l u t e phosphoric acid solutions and water i n the absence of carbon dioxide, found that dicalcium phosphate dihydrate  was  hydrolysed with the formation of a more basic calcium phosphate which he found to be octocalcium phosphate dihydrate.  Cole et a l . (10), i n his  investigation of phosphorus s o l u b i l i t y i n calcareous s o i l s , stated that the mean a c t i v i t y of dicalcium phosphate could be used to express phosphorus s i u b i l i t y i n calcareous s o i l s .  C a l c u l a t i o n of t h i s function, corrected  for differences i n the pH values, Ca concentrations, and i o n i c strengths which were encountered when a number of s o i l solutions were compared. Other factors besides moisture tension and s o i l reaction have been found to a f f e c t phosphate a v a i l a b i l i t y .  An extensive review of work  r e l a t i n g the effects of s o i l temperature on plant-tissue growth by Richards, Hagan and McCalla (49) have shown that, because of the complex chemistry of the s o i l , proper experimental procedures have not yet been developed  for evaluating these e f f e c t s .  r e s u l t s showing that more phosphorus was  Robinson (50) reported  fixed i n a sample of Dekalb  s o i l stored two months where temperatures fluctuated between 15°C 45°C than was  fixed i n the same s o i l stored at 3°C.  and  Wild (64) found that,  under s t e r i l e conditions, phosphate retention increases only s l i g h t l y as the temperature i s increased from 2 5 °  c  t o  35°C.  Beater (1) found  7 that i f the temperature i s increased up to 1Q0°C, the reaction proceeds much more r a p i d l y , though there i s no evidence that the t o t a l amount of phosphate retained was increased.  Several workers such as Ford (18)  and K e l l y (24) reported that clay or s o i l , when heated to temperatures o over 100 C, the hydrous minerals  lose water and hydroxyl groups, and  t h e i r capacity to r e t a i n phosphorus i s decreased. to the hydrous aluminum oxide.  According  This does not apply  to Wild (64) the e f f e c t of  temperature on the retention of phosphate under non-sterile conditions would be expected to depend on the r e l a t i v e rates of mineralization of s o i l organic matter, thus allowing release of phosphate and the absorption of phosphate by micro-organisms. In contrast to t h i s , Louw and Webley (33) have reported certain organisms that are able to dissolve t r i c a l c i u m phosphate and anhydrous dicalcium phosphate.  Mack and Barber (35) reported  that  s o i l s incubated  at -20.5°C for nine months released more phosphorus o o when leached with water at 16 C, than s o i l incubated at 27 C. Robinson et a l (50), working with monocalcium phosphate and red clover, found that phosphorus uptake and plant growth increased marketly with increasing o temperature of which the maximum temperature was 80 F.  Parus et a l  (42) also reported an increase i n phosphorus content i n tobacco leaf tissue with increasing temperature. In summary, i t i s evident that a great many investigations have been reported on the e f f e c t of water s o l u b i l i t y , granule s i z e , placement and the nature of associated compounds on the a v a i l a b i l i t y of s o i l phosphorus.  However, although there i s much information available  on these r e l a t i o n s h i p s , l i t t l e i s known about the actual influence of l e v e l s of s o i l moisture tension on the effectiveness of phosphatic materials i n s o i l s . Also, the reports of the e f f e c t of temperature on phosphate a v a i l a b i l i t y are somewhat contradictory. The investigations  8  which follow deal with the two aspects of phosphate a v a i l a b i l i t y s o i l s .  9 EXPERIMENTAL 1.  Materials  Two calcareous s o i l s were used to investigate the e f f e c t of s o i l moisture and s o i l temperature on phosphate a v a i l a b i l i t y .  The  two  s o i l s used were the Machete stony sandy loam and the N i s c o n l i t h clay loam taken from the southern region of B r i t i s h Columbia.  The Machete  stony sandy loam i s a Brown Wooded s o i l which i s found i n the North Thompson area.  I t i s thought that t h i s s o i l i s developed i n a l u v i a l fans.  In the p r o f i l e there i s a thin Aj horizon with a thin or absent A  2  horizon.  The substratum i s v a r i a b l e i n texture (22). The N i s c o n l i t h clay loam, previously c l a s s i f i e d as Westwold clay loam i s a dark grey G l e y s o l i c s o i l which i s found i n the North Okanagan V a l l e y (23). Some properties of these s o i l s were reported by Beaton and Nielsen (2)--see table 1. supplied with t o t a l  I t should be noted that both s o i l s were well  phosphorus.  The phosphatecompounds used i n these experiments were monoammonium phosphate, monocalcium phosphate, anhydrous dicalcium phosphate, calcium metaphosphate and hydroxyapatite. The chemical formulae and composition of these compounds are given i n table 2. Hignett ** presents some information on the s o l u b i l i t y i n water of several of the compounds used and these are given i n table 3. I t w i l l be noticed that no figure i s stated for calcium metaphosphate. Hignett states that this f e r t i l i z e r has no d e f i n i t e s o l u b i l i t y .  It  dissolves very slowly i n water with the formation of soluble nonorthophosphates which gradually hydrolyze to orthophosphates.  I f given s u f f i c i e n t  time, the hydrolysis w i l l go substantially to completion, forming p r i n c i p a l l y  10 monocalcium phosphate and dicalcium phosphate.  Substantially complete  hydrolysis may require about a year at room temperature. Reagent grade (A.C.S.) NH CaHPO, were used while Ca(PO )o 4 3 * Authority (T.V.A.).  H PO , Ca(tf PO ) . H 0 and 4 2 4 2 4 ^ 2 was obtained from the Tennessee V a l l e y  The hydroxyapatite was prepared i n the laboratory  after Egan et a l (16).  I t s calcium and phosphorus content was determined  to help i d e n t i f y and characterize i t .  X-ray analysis was also done on  the compound which revealed the absence of octocalcium phosphate. A l l the sources of phosphorus were passed through a 100 mesh screen to reduce the e f f e c t of p a r t i c l e s i z e . Two growth chambers were used i n one experiment to provide an adequate and constant source of r a d i a t i o n .  These growth chambers were  used i n the greenhouse and had dimensions of four feet by eight feet and were constructed of 1/4-inch f i r plywood.  Aluminum b u i l d i n g f o i l  was  attached to the inside surfaces of the chamber to reduce l i g h t absorption. The r a d i a t i o n source i n each chamber consisted of sixteen cool white fluorescent tubes which supply an average l i g h t i n t e n s i t y of 1600 foot candles, one foot above the plants.  These l i g h t s were raised as the plant  growth progressed. When the l i g h t s were on the temperature usually reached 25°C (71°F).  Alternating periods of seventeen hours of l i g h t  and seven hours of darkness were maintained throughout the duration of the experiment.  In these growth chambers were placed crocks containing  a l f a l f a plants. A constant temperature bath was used i n the temperature experiment to maintain constant s o i l temperatures.  I t was composed of a  stainless s t e e l tank 8 feet long by 4 feet wide and 1 foot 2 inches deep, a 1/3 H.P.  condensing u n i t , a 1 H.P. water c i r c u l a t o r and a heat exchanger.  11  Also attached to the tank was a thermostat which could control temperatures below the freezing point of water.  ** Hignett, T. P., Chief, Development Branch, Div. Chem. Development, Tennessee V a l l e y Authority. Personal communication, 1957.  I  12  2.  A n a l y t i c a l Methods (a) Determination of s o i l moisture tension curves  Small samples from both s o i l s were taken into the laboratory for the determination of t h e i r moisture tension curves. content was determined at 1/3, 2/3, 4 and 7.2 bars.  S o i l moisture  The pressure pot  technique (47) was used for the f i r s t two tensions, while the pressure membrane procedure (48) was used for the remaining determinations. I t i s evident from figure 1 that a given s o i l moisture tension the N i s c o n l i t h s o i l contained the most water. (b) Determination of phosphorus i n plant tissue Plant samples were wet ashed by the method suggested by Linder (32). Reagents:  1. 2.  Procedure: 1. 2.  Concentrated H SO, 30% H 0 * 2  2  2  3.  Transfer 1 gram plant material to 100 ml beaker Add 20ml. Cone. B^SO^and heat gently, u n t i l sample i s broken down Add 5ml. of 30% H 0 and heat gently  4.  This i s repeated u n t i l the solution i s clear  Phosphorus i n the wet ash was determined by a modified procedure (21) of the method outlined by Ritson and Mellon (25). (c) Determination of NaHCOj extractable phosphorus Immediately a f t e r the f i r s t harvest, small s o i l samples were taken from each pot, a i r dried and phosphorus extracted with NaHCO^ as described by Olsen et a l ( 4 0 ) .  The phosphorus present i n the extract was  determined by the Dickman and Bray method (14).  35  2.0  JL  ENERGY  Figure 1.  _L  4.0  6.0 OF  RETENTION  8.0  10  (BARS)  Moisture tension curves showing the relationship between s o i l moisture tension and the weight of water held on Machete stony sandy loam and N i s c o n l i t h clay loam s o i l s .  14 (d) Determination of Calcium, Calcium plus Magnesium and Phosphorus i n the s o i l extracts Calcium was determined by a modified cal-red indicator procedure of Patton (46). Procedure:  1. 2. 3. 4. 5. 6.  Take 5-15 ml. aliquot Make up to about 30ml. Add 4ml. of 8N KOH, l e t stand for 5 minutes Add about 30 mg. KCN Add about 30 mg. Hydroxylamine-hydrochloride Add 1 scoop of cal-red indicator  7. T i t r a t e with E.D.T.A. Calcium plus Magnesium was determined by the versene t i t r a t i o n and Bray (6) with erichrome black T as the indicator.  of Cheng  Phosphorus was  determined by Dickman and Bray (14). (e) Determination of C 0 - p a r t i a l pressure 2  S o i l samples were placed i n 250 ml. erlenmeyers and suspended i n 100 ml. of d i s t i l l e d water.  The s o i l samples were shaken on a  B u r r e l l Wrist-Action Shaker and a i r - C 0 for 24 hours.  2  mixture bubbled through continuously  The p a r t i a l pressure of C © was determined using the 2  s o l u b i l i t y of pure calcium carbonate and the following equation (26) pH  =  4.93 + 1/2 pCa - 1/2 log  P ^  (f) Determination of pH The pH of the s o i l suspensions was determined by a Cambridge bench model pH meter.  While the readings were being taken, a i r T C 0  2  mixture was bubbled into the suspension so as to maintain equilibrium conditions.  15 3.  Calculation of Ion A c t i v i t i e s  From the t o t a l concentrations of calcium and phosphorus measured, the a c t i v i t y of a p a r t i c u l a r ion species calculated by u t i l i z i n g d i s sociation constants and ion a c t i v i t y c o e f f i c i e n t s .  The a c t i v i t y coef-  f i c i e n t s were obtained from the Debye-Huckel equation* 2 _ -log y. z Az V I ±  1 + Ba.  v T  where V is the activity coefficient of the ion with valency z- . fc  I i s the i o n i c strength of the solution, A and B are constants for a given solvent and temperature, and a^ i s considered the e f f e c t i v e diameter of the ion i n solution (28). 2 I : J| £ c . z , where c i i i  i s the molar concentration of any ion i  and z^ i s i t s valence, (a) H P 0 a c t i v i t y 2  4  In a solution containing phosphate ions, the phosphate i n solution can be represented as:  where the f J brackets represent concentrations and the parentheses  ( )  activities. The d i s s o c i a t i o n constants for phosphoric acid can be expressed as (H PG ) 3  4  (H)(H P0 ) 2  (3)  4  K1 (HPO=)  K (H P0 ) 2  2  4  (4) (PO^ )  K K 2  3  (H P0 )  ( H V  2  4  (5)  16 Substituting equations  (3), (4) and (5) into equation (2) gives  p o t a l P} - (H )(H PG ) + (H POp + K  (HjPG^) + ^ K j O ^ P O p  +  2  4  2  k7  2  (H ) y=  (H )  +  +  /  ^5  solving f o r (BLPOT) r e s u l t s i n * * (Total P} (H ) + 1 +  K  l  >"  +  K2  r  + KjKg  <H )f-  (7)  (H ) >S  +  +  where K j " 7.51 x 10"  3  K = 6.33 x 10"  8  2  2  K = 4.73 x 10 3  (b) HP0° a c t i v i t y (HPO£) i s calculated from equation (4). (c) Ca * " a c t i v i t y 4  1  ++ Ca  ++ a c t i v i t y i s calculated from Ca  concentration by multi-  p l y i n g the a c t i v i t y c o e f f i c i e n t and the concentration.  In c a l c u l a t i n g  the a c t i v i t i e s of the i o n i c species i n these studies, i t was assumed that hydrogen, calcium and magnesium (where present) were the predominant cation species and that monovalent anions were i n equivalent concentrations. (d) pCaHPO^ a c t i v i t y This was calculated by adding the pCa and the pHPO^ a c t i v i t i e s .  17 Part I  1.  INFLUENCE OF SOIL MOISTURE TENSION ON THE YIELD AND UPTAKE OF PHOSPHORUS BY ALFALFA  Methods and Design () a  C o l l e c t i o n and treatment of s o i l s  In May  1959, approximately 1500 l b s . of the (0-6 inches) surface  layer of the two s o i l s , Machete stony sandy loam and N i s c o n l i t h clay loam, were obtained, a i r - d r i e d and seived through a 10 mesh screen. (h) Experimental design The experimental design for each s o i l was a 5 x 4  confounded  f a c t o r i a l r e p l i c a t e d three times as described by BVnet et a l (3).  The  s t a t i s t i c a l significance of the experimental r e s u l t s was tested by the analysis of variance.  I f the F test was  found to be s i g n i f i c a n t for a  treatment, the Duncan's multiple range test (15) was applied to the t r e a t ment means so as to compare and discuss them. (c) F e r t i l i z a t i o n In order that the influence of s o i l moisture l e v e l s on phosphorus uptake and y i e l d of a l f a l f a might be investigated, the phosphate sources outlined i n table 2 were applied at a rate equivalent to 120 l b . of P2°5 per acre. NH^  Since the monoammonium phosphate source contained nitrogen as  ion, an equivalent amount of nitrogen as NH^NO^ was added to a l l the  other phosphate treated pots. (d) Potting and  irrigation  One-gallon glazed porcelain crocks were used and 4,400 grams of s o i l added.  The empty crocks and the added s o i l weights were used along with  the information obtained from the moisture tension curves to maintain the moisture tension ranges. number of crocks. tension for the 0.2  Model R irrometers ** were placed i n h a l f the  These tensiometers were used to measure the s o i l moisture - 0.4 and 0.2  - 0.8 bar ranges.  The moisture tension  18 ranges of 0.2  - 2.0 and 0.2  - 6.0 bars were measured gravimetrically.  The moisture tension ranges were then four i n number: 0.2 0.2  - 0.4 bars ) - 0.8 bars )  measured and controlled with tensiometers  0.2 0.2  - 2.0 bars ) - 6.0 bars )  determined  gravimetrically  Once the upper l i m i t of any of these tension ranges was reached d i s t i l l e d water was added to lower the tension to 0.2 bars. procedure was repeated as often as necessary throughout  sufficient  This  the experiment.  A l l crocks were maintained at approximately 0.2 bars for f i v e weeks, before seeding. (e) Seeding On September 4, 1959,  the crocks were placed i n growth chambers,  and twenty innoculated Grimm a l f a l f a seeds were placed i n each crock. September 22, 1959,  On  these plants were thinned to leave a t o t a l of twelve  plants per pot. (f) Harvesting Three consecutive crops were harvested at the t h i r d blossom stage. The dates of harvest were: 1st cut 2nd cut  November 10, December 20,  1959 1959  3rd cut  February  1960  4,  The forage was removed by harvesting the tops, two inches above the s o i l . The plant tissue was dried at 65°C i n a forced draft, drying oven, weighed and the samples ground i n a Wiley M i l l to pass a 40 mesh screen.  The  tissue was then analysed for phosphorus as described previously. (g) Treatment of s o i l solutions A f t e r the f i r s t harvest, NaHCO-j extractable phosphorus was  determined  on each s o i l , arid at the end of the t h i r d harvest, dicalcium phosphate  19  a c t i v i t i e s o f the s o i l s o l u t i o n s were  calculated.  ** I r r o m e t e r M o i s t u r e I n d i c a t o r , manufactured by T. W. P r o s s e r Company Arlington, California.  Table I  Soil  Some properties of surface (0-6 inches) of the Machete stony sandy loam and the N i s c o n l i t h clay loam  Cation Exchange Capacity  m.e. per 100 gm of s o i l Machete stony sandy loam  21.41  Exchangeable Cations m.e. per 100gm of soil  "!""("  Ca  • "1"  Mg  K  pH of Soil Paste  Conductivity m.mhos  Organic Total ExtractMatter able P Per cent ppm P ppm H C0 NaHC0  + Na  17.55 3.43 0.38 0.05  Gonteni of Sand Silt & Clay  2  7.68  1.90  4.4  855  14  3  30  57.7 22.4 19.9  N i s c o n l i t h clay loam  35.50  21.09 11.43 2.67 0.31 7.60  2.94  4.3  971  8  40  42.9 30.0 27.1  IV)  O  Table 2  Nature of phosphate compounds used i n experiments  Formula  Common Name  N Per  cent  ?  CaO per cent  2°5  per  cent  P 0 /CaO 2  5  weight ratio  Monoammonium phosphate  12.2  61.7  -  -  Ca(H PG4) H 0  Monocalcium phosphate  -  56.3  22.3  2.52  Ca HPO. 4  Dicalcium phosphate(Anhydrous)  -  52.18  41.2  1.26  Calcium Metaphosphate  -  63.1  27.1  2.32  Hydroxyapatite  -  43.0  55.9  .77  N H  4 2 H  P 0  4  2  2  Ca(P0 ) 3  2  2  Ca (PO^) (0H) 10  6  2  Table 3  Water s o l u b i l i t y of the f e r t i l i z e r s at various temperatures NH4H P0 2  400 gm/liter a t 15°C  4  Ca(H P0 ) H 0  40 gm/liter at 15°C  CaH P 0  0.2 gm/liter a t 30°C  2  4  2  2  4  Ca(P0,j)  not known  2  Ca (PO4) (OH) 10  6  2  2.09 x 10~4 gm/liter at 25°C  Y i e l d of a l f a l f a at four moisture tension ranges i n Machete stony sandy loam treated with phosphate carriers of different water s o l u b i l i t y  Table 4.  Phosphate carriers (applied at a rate equivalent to 120 lbs P205per acre  Mean yields of 3 cuttings -gm oven dry material per pot at four moisture tension ranges - bars 0.2-0.4 0.2-0.8 0.2-2.0  Means over phosphate carriers 0.2-6.0  7.77  7.13  9.17  7.10  7.80  ab  Ca(H P0 ) H 0  8.93  7.90  9.27  7.60  8.42  ab  CaHPO^  8.37  8.67  9.33  8.57  8.73  a  8.73  8.27  9.70  8.20  8.66  a  8.30  6.33  8.70  6.80  7.53  b  8.42 ab  7.65 b  9.18 a  7.65 b  NH H P0 4  2  4  2  4  Ca(P0 ) 3  C a  l0  ( P O  2  2  2  4>6  ( O H )  2  Means over moisture tension ranges  Any two means not having l e t t e r s i n common are s i g n i f i c a n t l y d i f f e r e n t at the 5 per cent l e v e l by the Duncan Test.  Any two means with the same l e t t e r are not s i g n i f i c a n t l y d i f f e r e n t .  Table 5.  Y i e l d of a l f a l f a at four moisture tension ranges i n N i s c o n l i t h clay loam treated with phosphate carriers of d i f f e r e n t water s o l u b i l i t y  Phosphate carriers (applied at a rate equivalent to 120 lbs P 0rj per acre 2  N  W ° 4  Ca(H P0 ) H 0 2  4  2  2  CaHPO. 4 Ca(P0 ) 3  C a  l0  ( P  Mean yields of 3 cuttings -gm oven dry material per pot at four moisture tension ranges - bars 0.2-0.4 0.2-0.8 0.2-2.0  0.2-6.0  9.33  11.67  11.93  8.20  10.27  a  10.97  10.53  11.37  8.23  10.28  a  9.33  11.17  11.10  10.13  10.73  a  9.27  11.60  11.60  10.97  a  9.87  a  13.63  2  °4 6 )  ( O H )  2  Means over moisture tension ranges  9.90  10.80  9.33  10.63 a  10.69 a  11.30 a  Means over phosphate carriers  9.43  9.08 b  Any two means not having l e t t e r s i n common are s i g n i f i c a n t l y d i f f e r e n t at the 5 per cent l e v e l by the Duncan Test.  Any two means with the same l e t t e r are not s i g n i f i c a n t l y d i f f e r e n t .  24 2.  Results and Discussion (a) Yields The y i e l d s of a l f a l f a on the two s o i l s , Machete stony sandy loam  and N i s c o n l i t h clay loam are summarized i n tables 4 and 5 respectively, and g r a p h i c a l l y presented i n figures 2 and 3. The y i e l d s values from the Machete stony sandy loam when subjected to an analysis of variance (Appendix 1) showed that the effect of phosphorus source on y i e l d was s i g n i f i c a n t at the 5% p r o b a b i l i t y l e v e l (P= 0.05) as was the moisture tension at both P= 0.05 and P= 0.01. The interaction of moisture tension and phosphorus source was not s i g n i f i c a n t . Since the effects of moisture tension and phosphorus source were found to be s i g n i f i c a n t , the y i e l d means for these two factors were compared using Duncans multiple range test (15) and these comparisons are given i n table 4. The use of the least s i g n i f i c a n t difference for comparisons between means was thought of, but according to Steel and T o r r i e  (56)  t h i s s t a t i s t i c a l tool should only be used for independent comparisons.  In  a comparison of means where one mean occurs more than once to be compared the Duncan's new multiple range test should be used. S i g n i f i c a n t differences i n y i e l d means were observed between tension ranges of 0.2-2.0 and 0.2-0.8 and between 0.2-2.0 and 0.2-6.0 bars. S i g n i f i c a n t y i e l d differences, as i l l u s t r a t e d i n table 4, were obtained between the phosphorus sources of hydroxyapatite and dicalcium  phosphate  and between calcium metaphosphate and hydroxyapatite. In Appendix 7, the analysis of variance for the y i e l d data from the N i s c o n l i t h clay loam showed that the effects of moisture tension and the i n t e r a c t i o n of moisture tension and phosphorus source were s i g n i f i c a n t . Phosphorus source alone had no s i g n i f i c a n t e f f e c t on the y i e l d of a l f a l f a .  25 The comparison of y i e l d means with respect to the effects of moisture tensions showed s i g n i f i c a n t differences between tension ranges of 0.2-6.0 and 0.2-0.4, 0.2-6.0 and 0.2-0.8 and between 0.2-6.0 and 0.2-2.0 bars. See table 5. A comparison of mean y i e l d s from the Machete stony sandy loam (table 4) shows that the effects of monoammonium phosphate and monocalcium phosphate did not cause a sijpiif leant increase i n y i e l d over hydroxyapatite. Beaton and Nielsen (2) working with t h i s s o i l also found that the monocalcium phosphate was i n e f f e c t i v e .  Monoammonium phosphate, though i n i t i a l l y high  i n water-soluble phosphorus, gave disappointing r e s u l t s . for  The explanation  this might be the p r e c i p i t a t i o n of hydroxyapatite i n calcareous s o i l s  as suggested by Clark et a l (8). According to Beaton and Nielsen (2), the formation of hydroxyapatite i s enhanced because of the soluble ammonium phosphate produces the P 0 ions for i t s p r e c i p i t a t i o n . 4 =  Although anhydrous  dicalcium phosphate d i d not give a s i g n i f i c a n t l y greater y i e l d than calcium metaphosphate, monocalcium phosphate and monoammonium phosphate, there was, however, a trend towards decreasing y i e l d s i n that order.  Thomas (60),  found anhydrous dicalcium phosphate a more e f f i c i e n t source of phosphorus than concentrated superphosphate ( p r i n c i p a l component - monocalcium phosphate) for  oats.  In opposition to this Terman et a l (59) believes that the release  of phosphorus from fine anhydrous dicalcium phosphate i s not dependent on i t s content of water soluble phosphorus and that granular anhydrous dicalcium phosphate dissolved too slowly to supply adequate phosphorus.  In t h i s study  calcium metaphosphate was more e f f e c t i v e than monoammonium phosphate i n increasing a l f a l f a y i e l d .  Norland et a l (39) found calcium metaphosphate a  more e f f i c i e n t source of phosphorus for long term e f f e c t since i t releases i t s phosphorus very slowly.  According to Terman (58) the rate and extent  of d i s s o l u t i o n and hydrolysis of calcium metaphosphate vary with s o i l properties, but the fundamental s o i l properties involved are not yet defined.  26 Terman et a l (59) working with calcareous s o i l s found monocalcium phosphate anhydrous dicalcium phosphate, and hydroxyapatite ryegrass y i e l d i n the order given. anhydrous dicalcium phosphate was  e f f e c t i v e i n increasing  In t h i s study i t was  found that  the most e f f e c t i v e of the three.  In the l i g h t of the theories on the calcium phosphates and t h e i r reaction products, there seem to be no reasonable explanation for the monocalcium phosphate's behaviour on the s o i l . In the N i s c o n l i t h clay loam, phosphorus sources had no s i g n i f i c a n t e f f e c t on y i e l d but the trend of effectiveness was  i n the order: calcium  metaphosphate, anhydrous dicalcium phosphate, monocalcium phosphate, monoammonium phosphate and hydroxyapatite.  I t w i l l be noticed that the  difference i n the order of effectiveness of phosphorus source, on a l f a l f a y i e l d , for both s o i l s d i f f e r e d only i n the f i r s t and second compounds which were reversed. Growth response to s o i l moisture tension on the Machete stony sandy loam showed that 0.2-2.0 bars range out yielded a l l the other tension ranges and was  s i g n i f i c a n t l y greater than the 0.2-0.8 and the 0.2-6.0  bars tension.  With the N i s c o n l i t h clay loam only the 0.2-6.0 bars tension  range was this may  s i g n i f i c a n t l y less than the other three.  The explanation for  be seen i n figure 1, which shows that the moisture retained i n the  N i s c o n l i t h s o i l up to tensions of 6.0 bars, was the Machete s o i l at the same tension.  greater than that held i n  Taylor (57) stated that maximum  y i e l d s of a l f a l f a hay could be obtained on well-drained s o i l s that were kept continuously moist.  He also concluded  that maximum a l f a l f a seed  production could be expected i f the mean s o i l moisture tension does not exceed two bars u n t i l a f t e r f u l l bloom.  27  I f the s u i t a b i l i t y of phosphate materials was being investigated at a single s o i l moisture tension approaching 0.2-2.0 bars, probably l i t t l e or no difference among sources would be observed.  V  Figure 2.  The effect of s o i l moisture tension and phosphate f e r t i l i z e r s on the y i e l d of a l f a l f a grown on the Machete stony sandy loam.  29  Figure 3.  The effect of s o i l moisture tension and phosphate f e r t i l i z e r s on the y i e l d of a l f a l f a grown on N i s c o n l i t h clay loam.  Table 6.  Phosphorus content i n a l f a l f a at four moisture tension ranges i n Machete stony sandy loam treated with phosphate c a r r i e r s of different water s o l u b i l i t y  Phosphate carriers (applied at a rate equivalent to 120 lbs P 0^ per acre)  Mean phosphorus content of 3 cuttings -per cent at four moisture tension ranges -bars 0.2-0.4 0.2-0.8 0.2-2.0 0.2-6.0  NH H P0  .234  .195  .202  .234  .216  a  Ca(H P0 ) H 0  .186  .202  .217  .171  .193  ab  CaHPO. 4  .207  .199  .207  .195  .202  a  .170  .203  .201  .168  .185  ab  .161  .190  .167  .175  .173  b  .191 a  .197 a  .199 a  .188 a  2  4  2  4  2  4  Ca(P0 ) 3  C a  i0  ( P  2  2  2  °4 6 )  ( 0 H  2  Means over moisture tension ranges  Means over phosphate carriers  Any two means not having l e t t e r s i n common are s i g n i f i c a n t l y d i f f e r e n t at the 5 per cent l e v e l by the Duncan Test.  Any two means with the same l e t t e r are not s i g n i f i c a n t l y d i f f e r e n t .  Table 7.  Phosphorus content i n a l f a l f a at four moisture tension ranges i n N i s c o n l i t h clay loam treated with phosphate carriers of different water s o l u b i l i t y .  Phosphate carriers (applied at a rate equivalent to 120 lbs P2O5 per acre)  Mean phosphorus content of 3 cuttings -per cent at four moisture tension ranges -bars 0.2-0.4 0.2-0.8 0.2-2.0 0.2-6.0  NH H PO^  .244  .178  .222  .223  .216  a  Ca(H P0 ) H 0  .227  .226  .244  .214  .227  a  CaHPO. 4  .215  .212  .220  .205  .213  a  .215  .188  .224  .235  .215  a  .203  .196  .217  .207  .206  b  .220 a  .200 b  .225 a  .217 ab  4  2  2  4  Ca(P0 ) 3  2  2  2  Ca (P0 ) (OH) 1Q  4  6  2  Means over moisture tension ranges  Means over phosphate carriers  Any two means not having l e t t e r s i n common are s i g n i f i c a n t l y d i f f e r e n t at the 5 per cent l e v e l by the Duncan Test.  Any two means with the same l e t t e r are not s i g n i f i c a n t l y d i f f e r e n t .  32  (b)  Phosphorus content  The phosphorus content i n a l f a l f a tissue grown on both Machete stony sandy loam and the N i s c o n l i t h clay loam are given i n tables 6 and 7 and the graphical presentation i n figures 4 and 5.  An analysis of  variance of the phosphorus content data from the Machete s o i l (Appendix 2) showed that the effect of phosphorus source was s i g n i f i c a n t at P r 0.01 and P = 0.05 while the effect of the interaction of moisture tension and phosphorus source was s i g n i f i c a n t at P ; 0.2. A comparison of phosphorus content means, as shown i n table 6, with respect to the phosphate c a r r i e r s showed that s i g n i f i c a n t differences were obtained between monoammonium phosphate and hydroxyapatite and between dicalcium phosphate and hydroxyapatite. For the N i s c o n l i t h clay loam, an analysis of variance showed that moisture tension had a s i g n i f i c a n t e f f e c t (at P = .10) on the phosphorus content.  In this s o i l , differences i n percent phosphorus were s i g n i f i c a n t  between tension ranges of 0.2-2.0 and 0.2-0.8 and 0.2-0.4 and 0.2-0.8 bars. Maximum phosphorus content i n plants occurred at the 0.2-2.0 bars tension. Worthy of mention also i s the fact that maximum percent phosphorus i n plant tissue from Machete s o i l occurred at a tension range of 0.2-2.0 bars even though s i g n i f i c a n t differences between percent phosphorus means were not observed. I t appears from the above r e s u l t s that monoammonium phosphate and anhydrous dicalcium phosphate were the most e f f e c t i v e i n increasing the phosphorus content of a l f a l f a on the Machete s o i l .  With respect to  monoammonium phosphate, this observation i s i n agreement with results obtained by Norland et a l (39), (2).  \;. Owens et a l (41) and Beaton and Nielsen  The high phosphorus coitent i n the a l f a l f a tissue caused by monoammonium  phosphate must, i n part, be due to the high water s o l u b i l i t y of this material.  33 The e f f e c t of the NH* ion i n increasing phosphorus percentage may be present.  This seems to agree with Rennie et a l (46) who reported this  effect with young wheat plants and with Bouldin (4) who worked with oat plants.  Bouldin modified his statement by saying that the effect might  be dependent upon s o i l properties. The results obtained from anhydrous dicalcium phosphate i s surprising since most investigators report that i t i s very stable and that i t s reaction with s o i l constituents i s very slow and i s classed as water-insoluble. As reported previously, phosphorus source had no s i g n i f i c a n t e f f e c t on the phosphorus content i n a l f a l f a  tissue from the N i s c o n l i t h  s o i l while moisture tension had a s i g n i f i c a n t e f f e c t at a p r o b a b i l i t y l e v e l of 10%. In agreement with r e s u l t s reported herein, Corgan et a l (13),  subjecting kidney beans to a moisture stress equivalent to 0.5M  manlntol and phosphorus concentrations up to 100 ppm, detected no op  s i g n i f i c a n t change i n the rate of P  uptake.  Fawcett et a l (17) also  reported no s i g n i f i c a n t difference i n phosphorus uptake when wheat plants were subjected to moisture percentages ranging from 18 to w i l t i n g percent and phosphorus levels from 50-100 ppm. to those obtained i n figure 4. at a moisture content of 8%.  Their graph showed trends similar  Here the highest phosphorus uptake occurred  Simpson (54) working with superphosphate and  oats at two extreme moisture tensions obtained reduced phosphorus.uptake with increased moisture tension. I t may be concluded that the phosphorus content of the a l f a l f a tissue was l i t t l e affected between the moisture tension ranges of 0.2-0.4 and 0.2-6.0 bars.  As indicated i n figure 4 and 5, however, there i s a trend  towards maximum phosphorus content i n the plant tissue at a moisture tension range of 0.2-2.0 bars.  Figure 4.  The effect of s o i l moisture tension and phosphate f e r t i l i z e r s on the per cent of phosphorus i n a l f a l f a tissue on Machete stony sandy loam.  35  Figure 5.  The effect of s o i l moisture tension and phosphate f e r t i l i z e r s on the per cent phosphorus i n a l f a l f a tissue on the N i s c o n l i t h clay loam.  Table 8.  Phosphorus uptake by a l f a l f a at four moisture tension ranges i n Machete stony sandy loam treated with phosphate c a r r i e r s of d i f f e r e n t water solubility.  Phosphate carriers (applied at a rate equivalent to 120 lbs  Mean phosphorus uptake of 3 cuttings -gm x 10" per pot at four moisture tension ranges -bars 0.2-0.4 0.2-0.8 02-2.0 0.2-6.0  Means over phosphate carriers  1.770  1.390  1.820  1.650  1.660  a  Ca(H P0 ) H 0  1.676  1.562  2.008  1.316  1.640  a  CaHPO. 4  1.749  1.695  1.920  1.661  1.756  a  1.471  1.691  1.892  1.405  1.615  a  1.320  1.195  1.478  1.199  1.298  b  Means over moisture  1.598  1.506  1.824  1.446  tension ranges  a  a  a  a  P  2°5  p  e  r  NH H P0 A  2  a c r e  4  2  4  Ca(P0 ) 3  C a  lo  ( P G  )  2  2  2  4 6 )  ( O H )  2  2  Any two means not having l e t t e r s i n common are s i g n i f i c a n t l y d i f f e r e n t at the 5 per cent l e v e l by the Duncan Test.  Any two means with the same l e t t e r are not s i g n i f i c a n t l y d i f f e r e n t .  Table 9.  Phosphorus uptake by a l f a l f a at four moisture tension ranges i n N i s c o n l i t h clay loam treated with phosphate carriers of d i f f e r e n t water s o l u b i l i t y .  Phosphate carriers (applied at a rate equivalent to 120 lb P 0 j per acre)  Mean phosphorus uptake of 3 cuttings four moisture -gm x 10 " per pot at tension ranges - bars 0.2-0.8 0.2-2.0 0.2-6.0 0.2-0.4  NH H P0  2.301  2.101  2.710  1.822  2.233  a  Ca(H P0 ) H 0  2.471  2.536  2.712  1.742  2.365  a  CaHP0  2.034  2.451  2.724  2.071  2.320  a  Ca(P0 ) 2  2.954  1.754  2.615  2.201  2.381  a  2.096  2.101  2.078  1.972  2.062  a  2.371 ab  2.189 a  2.568 b  1.962 a  2  4  2  4  2  4  2  2  4  3  C a  10  ( P 0  4>6  ( G H  ^  Means over s o i l moisture tension  z  Means over phosphate carriers  Any two means not having l e t t e r s i n common are s i g n i f i c a n t l y d i f f e r e n t at the 5 per cent l e v e l by the Duncan test.  Any two means with the same l e t t e r are not s i g n i f i c a n t l y  different.  38 (c) Uptake of phosphorus The t o t a l amount of phosphorus removed by a l f a l f a from both s o i l s are given i n tables 8 and 9 and a graphical presentation shown i n figures 6 and- 7.  An analysis of variance of phosphorus y i e l d data (see Appendix 3)  showed that the effects of s o i l moisture tension and phosphorus source were s i g n i f i c a n t  at P= 0.05 and P= 0.01 on the Machete stony sandy loam.  Data from the N i s c o n l i t h clay loam (see Appendix 9) showed that the e f f e c t of moisture tension was s i g n i f i c a n t at P= 0.01 and the i n t e r a c t i o n of moisture tension and phosphorus source at P= 0.2. not  Phosphorus source was  significant. Comparison of phosphorus y i e l d means as i l l u s t r a t e d i n table 8, with  respect to moisture tension on the Machete s o i l showed that  significant  differences existed between the means at moisture tensions of 0.2-2.0 and 0.2-0.8 and between 0.2-2.0 and 0.2-6.0 bars.  S i g n i f i c a n t differences  between phosphorus y i e l d means with respect to phosphorus source showed that differences existed only between hydroxyapatite and each of the other phosphorus sources. For  the N i s c o n l i t h s o i l (see table 9) a comparison of phosphorus  y i e l d means with respect to moisture tension showed that the means at 0.2-2.0 bars tension was s i g n i f i c a n t l y d i f f e r e n t from that at 0.2-0.8 bars. In discussing t o t a l phosphorus removed or the y i e l d of phosphorus, as i t i s sometimes termed, one should note that i t i s sometimes selected as a better indicator than y i e l d f o r estimating f e r t i l i z e r a v a i l a b i l i t y . I t i s less influenced by differences i n the a v a i l a b i l i t y of other nutrients than i s y i e l d of dry matter.  Since the y i e l d of phosphorus i s determined  by multiplying y i e l d of dry matter by per cent phosphorus, the results obtained depends on whether the per cent phosphorus i s great enough to  39 change the e f f e c t obtained from the y i e l d of dry matter. The maximum phosphorus y i e l d was produced at the moisture tension range of 0.2-2.0 bars as was the y i e l d of dry matter. factors favouring maximum phosphorus y i e l d are many.  The  At this moisture  tension range of 0.2-2.0 bars, b i o l o g i c a l a c t i v i t y can be at i t s maximum. The s o i l i s not wet; i t s aeration i s good.  In addition to these factors,  according to Taylor (57) i t may be c h a r a c t e r i s t i c of the plant species to do well i n a continuously moist condition.  Hydroxyapatite seemed to be the  only phosphorus source that had a very limited e f f e c t on phosphorus y i e l d when the means are compared.  As a source of phosphorus for plants,  hydroxyapatite has been known to be i n f e r i o r .  Again, at the moisture  tension range of 0.2-2.0 bars on the N i s c o n l i t h s o i l the phosphorus y i e l d was greatest and s i g n i f i c a n t differences existed between i t and moisture tension ranges of 0.2-0.8 and 0.2-6.0. The moisture treatment of 0.2-2.0 bars must be considered optimum for a l f a l f a growth.  Figure  6.  The e f f e c t of s o i l moisture tension and phosphate f e r t i l i z e r s on the y i e l d of phosphorus on the Machete stony sandy loam.  41  Figure 7.  The effect of s o i l moisture tension and phosphate f e r t i l i z e r s on the y i e l d of phosphorus on the N i s c o n l i t h clay loam.  Table 10.  NaHC0 extractable phosphorus remaining i n the Machete stony sandy loam at the end of the 1st a l f a l f a cutting. 3  Phosphate carriers (applied at a rate equivalent to 120 lb P 0,-per acre)  Mean phosphorus content of 3 replicates -ppm at four moisture tension ranges -bars 0.2-0.4 0.2-0.8 0.2-2.0 0.2-6.0  Means over phosphate c a r r i e r s  NH H P0  30.6  17.3  15.3  17.3  20. 16  a  Ca(H P0 )2H 0  17.3  22.0  39.3  11.3  22. 50  a  CaHPO. 4  24.6  14.0  20.0  15.3  18. 50  ab  16.0  24.0  13.3  10.6  16. 00  ab  9.3  10.0  9.3  7.3  9.00  19.60 a  17.46 a  19.46 a  12.40 a  2  4  2  4  2  4  Ca(P0 ) 3  2  2  Ca (PO ) (OH) 10  4  6  2  Means over moisture tension ranges  b  Any two means not having l e t t e r s i n common are s i g n i f i c a n t l y d i f f e r e n t at the 5 per cent l e v e l by the Duncan Test.  Any two means with the same l e t t e r are not s i g n i f i c a n t l y d i f f e r e n t .  Table 11.  NaHCO extractable phosphorus remaining i n the N i s c o n l i t h clay loam at the end of the 1st a l f a l f a cutting.  Phosphate carriers (applied at a rate equivalent to 120 lb ?2°5 P )  Mean phosphorus content of 3 replicates -ppm at four moisture tension ranges -bars 0.2-0.4 0.2-0.8 0.2-2.0 0.2-6.0  Means over phosphate carriers  NH H P0  51.3  40.6  59.3  43.3  48.66  a  Ca(H P0 ) H 0  44.0  56.0  36.0  43.0  44.75  a  CaHPO,  42.3  38.3  59.3  44.6  46.16  a  44.0  46.3  42.3  46.3  44.75  a  33.3  37.3  24.6  26.6  30.50  b  43.00 a  43.73 a  44.33 a  40.80 a  e r  4  2  4  2  4  Ca(P0 ) 3  C a  lO  a c r e  ( P G  2  2  2  4 6 )  ( O H  >2  Means over moisture tension ranges  Any two means not having l e t t e r s i n common are s i g n i f i c a n t l y d i f f e r e n t at the 5 per cent l e v e l by the Duncan test.  Any two means with the same l e t t e r are not s i g n i f i c a n t l y d i f f e r e n t .  44 (d) NaHCO^ extractable phosphorus The results obtained for the 0.5N NaHCG^ extractable phosphorus on both s o i l s are given i n tables 10 and 11 and the graphical presentations are given i n figures 8 and 9. The analyses of variance of the phosphorus data (see Appendices 4 and 10) showed that the effect of phosphorus source was s i g n i f i c a n t at P = 0.10. Usually at these l i m i t s of confidence, comparisons of means are  not made, but i t s h a l l be done here because i t i s f e l t that differences  i n means are wide enough to warrant comparison. A comparison of the phosphorus means from the Machete  soil  (table 10) showed that s i g n i f i c a n t differences between monocalcium phosphate and hydroxyapatite and between monoammonium phosphate and hydroxyapatite. For  the N i s c o n l i t h s o i l (table 11) s i g n i f i c a n t difference between mono-  ammonium phosphate and hydroxyapatite was observed. I t i s evident from the r e s u l t s that the only treatment having any s i g n i f i c a n t e f f e c t on the NaHCO^ extractable phosphorus was the source of phosphorus.  The more soluble sources of phosphorus such as  monoammonium phosphate and monocalcium phosphate on the Machete s o i l , provided the greatest amounts of available phosphorus while hydroxyapatite provided the least available phosphorus as indicated by the NaHCO^ extractable phosphorus.  45  Figure 8.  The effect of s o i l moisture tension and phosphate f e r t i l i z e r s on 0.5N NaHCO extractable phosphorus i n the Machete stony sandy loam.  Figure  9.  The effect of s o i l moisture tension and phosphate f e r t i l i z e r s on 0.5N NaHCO-j extractable phosphorus i n the N i s c o n l i t h clay loam.  Table 12.  Dicalcium phosphate a c t i v i t i e s i n Machete stony sandy loam calculated using Ga, Mg, and P concentrations i n the s o i l solutions  Phosphate carriers (applied at a rate equivalent to 1 2 0 lb P 0c per acre) 2  NH H P0 4  2  4  Ca(H.P0,)_IL0  CaHPO, 4 Ca(P0 ) 3  L O  Means over phosphate carriers  0 . 2 - 0 . 4  0 . 2 - 0 . 8  0 . 2 - 2 . 0  0 . 2 - 6 . 0  8.29  8.22  8.37  8.40  8.32  8.30  8.36  8.52  8.47  8.41  8.03  8.49  8.66  8.39  8.40  a  8.38  8.39  8.76  8.26  8.45  a  9.01  8.64  8.84  8 . 6 9  8 . 8 0  8.40 a  8.42 a  8.63 a  a a  4 2 2  2  Ca  Mean dicalcium phosphate a c t i v i t i e s of 3 replicates - molar at four moisture tension ranges - bars  2  <;P0 ) (OH) 4  6  2  Means over moisture tension ranges  8.44 a  Any two means not having letters i n common are s i g n i f i c a n t l y d i f f e r e n t at the 5 per cent l e v e l by the Duncan test.  Any two means with the same l e t t e r are not s i g n i f i c a n t l y  different.  Table 13. Dicalcium phosphate a c t i v i t i e s i n N i s c o n l i t h clay loam calculated using Ca, Mg, P concentrations i n s o i l solutions  Phosphate carriers (applied at a rate equivalent to 120 lb P 0, per acre)  Mean dicalcium phosphat e a c t i v i t i e s of 3 replicates -molar at four moisture tension ranges -bars 0.2-0.4 0.2-0.8 0.2-2.0 0.2-6.0  NH H P0  7.63  7.75  7.52  7.68  7.65  a  Ca(H P0 ) H 0  7.59  7.75  7.67  7.53  7.64  a  CaHPO, 4  7.60  7.86  7.82  7.68  7.74  ab  7.54  7.46  7.69  7.78  7.67  ab  7.80  7.82  7.97  7.80  7.85  b  7.63 a  7.76 a  7.74 a  7.70 a  o  4  2  4  2  4  Ca(P0 ) 3  C a  i0  ( P  2  2  2  °4 6 )  ( 0 H )  2  Mean over moisture tension ranges  Means over phosphate carriers  Any two means not having l e t t e r s i n common are s i g n i f i c a n t l y d i f f e r e n t at the 5 per cent l e v e l by the Duncan test.  Any two means with the same l e t t e r are not s i g n i f i c a n t l y d i f f e r e n t .  49 (e) Dicalcium phosphate a c t i v i t i e s The r e s u l t s of the dicalcium phosphate a c t i v i t y , calculated from the calcium, magnesium and phosphorus concentrations i n the s o i l extracts are given i n tables 12 and 13.  An analysis of variance of these a c t i v i t y  means are shown i n Appendices 5 and 11.  In both the Machete and N i s c o n l i t h  s o i l s the e f f e c t of phosphorus source was former s o i l at P =0.01  found to be s i g n i f i c a n t , i n the  and the l a t t e r at P = 0.20.  Comparison of the dicalcium phosphate a c t i v i t y means (table  12)  the Machete s o i l showed that s i g n i f i c a n t differences were obtained between hydroxyapatite and a l l the other phosphate sources. differences were found between the other sources.  No  significant  For the N i s c o n l i t h  clay loam, table 13 shows that s i g n i f i c a n t differences between dicalcium phosphate a c t i v i t y means were observed for hydroxyapatite and monocalcium phosphate and between hydroxyapatite and monoammonium phosphate. The dicalcium phosphate a c t i v i t y means were determined  i n the  hope that they could be used to express the phosphorus s o l u b i l i t y of fertilizers  i n calcareous s o i l s as had been done by Cole and Olsen (10).  These authors bound that the values of the mean a c t i v i t y of dicalcium phosphate i n equilibrium s o i l solutions increased as a d i r e c t function of the amount of phosphate added as concentrated superphosphate.  However,  the r e s u l t s obtained as indicated i n tables 12 and 13 were not i n agreement. The explanation may be due to the higher rates of phosphate applications which Cole and Olsen used.  In t h e i r studies they applied superphosphate  up to rates equivalent to 1200 lb P2O5 P required as much as 210 lb P2O5 P  e r  acre and they stated that i t  e r  acre to show any increase i n dicalcium  phosphate a c t i v i t y i n the s o i l extracts. The rate of phosphate used i n the present study was  equivalent to 120 lb P o 0  s  per acre.  50 This method appears to be a doubtful one for evaluating the s o l u b i l i t y of phosphatic f e r t i l i z e r materials at low rates.  Also  according to Lehr et a l (29) and Lindsay et al(32), there i s a tendency for reaction products to be concentrated i n a rather r e s t r i c t e d zone about the f e r t i l i z e r p a r t i c l e . important.  Secondly, the time of the reaction i s  With increasing time the f e r t i l i z e r - s o i l reaction products  become more nearly a l i k e .  For this reason, i f the s o i l  fertilizer  reactions have proceeded for a lengthy period, the calcium phosphate reaction products i n a l l p r o b a b i l i t y would have reached the following situation: Phosphate f e r t i l i z e r _»> calcium phosphates  +  complex c r y s t a l l i n e compounds  dicalcium phosphate OCP —*> dihydrate DCPD octocalcium phosphate <*/  DCPa anhydrous dicalcium phosphate  HA p  hydroxyapatite  51 Part II  1.  EFFECT OF TEMPERATURE ON THE YIELD AND UPTAKE OF PHOSPHORUS BY ALFALFA  Methods and Design  (a) Experimental design In May 1959, using the two s o i l s Machete stony sandy loam and N i s c o n l i t h clay loam, an experiment was designed to study the effect of two temperatures and f i n e phosphate sources on the a v a i l a b i l i t y of phosphorus to a l f a l f a i n calcareous s o i l s . The experimental design used for both s o i l s was a 5 x 2 f a c t o r i a l replicated four times., A l l experimental r e s u l t s were subjected to an analysis of variance.  When significance was observed the Duncan*s mul-  t i p l e range test was used to compare treatment means. (b)  Fertilization  The f i v e sources of phosphates used were the same i n Part I, v i z : monoammonium phosphate, monocalcium phosphate, anhydrous dicalcium phosphate, calcium metaphosphate and hydroxyapatite. equivalent to 120 lbs of P2O5 per acre.  These were applied at a rate Since monoammonium phosphate  contained nitrogen as NH+ ion, an equivalent amount of nitrogen as ammonium n i t r a t e was added to the other phosphate sources. (c) Potting and i r r i g a t i o n 4,400 grams of each s o i l was added to a t o t a l of 80 pots.  These  pots and t h e i r s o i l s were weighed so that the weight of d i s t i l l e d water could be added to keep the moisture tension range between 0.2 and 0.8 bars. (d) Maintenance of temperature These 80 pots were separated into two sets of 40 each.  The one  set containing the Machete stony sandy loam, and the other containing the N i s c o n l i t h clay loam. Each of these sets of 40 was further divided into two sets of 20 each. Twenty pots of each s o i l were placed on the greenhouse  52 o bench where the temperature was 24 C and the rest placed i n a bath maintained at 10°G.  temperature  Hence the temperature bath contained a t o t a l  of 40 pots, 20 of which belonged to each s o i l . (e) Seeding and harvesting These crocks were allowed to stand i n a moist condition for about one month a f t e r the f e r t i l i z e r s had been intimately mixed with the s o i l . At the end of this time, Grimm a l f a l f a 20, 1959,  seeds were planted and on November  the stands were thinned to ten plants per pot.  The plants  were harvested as follows: 1st cut 2nd cut 3rd cut  A p r i l 22, 1960 June 5, 1960 J u l y 7, 1960  -  The forage was removed by harvesting the tops two inches above the s o i l . o The plant tissue was dried at 65 C, weighed, and the samples ground i n a Wiley M i l l to pass a 40 mesh screen.  The tissue was analysed for  phosphorus as explained before. (f) Treatment of s o i l solutions NaHCO^ extractable phosphorus was determined a l l 80 pots of each s o i l type.  i n the s o i l of  Table 14  Y i e l d of a l f a l f a at two s o i l temperatures 10°C and 24°C i n Machete stony sandy loam treated with phosphate c a r r i e r s of different water s o l u b i l i t y  Phosphate carriers (applied at a rate equivalent to 120 l b P2O5 per acre)  Yields of 3 cuttings -gm oven dry material per pot at two s o i l temperatures - C 10 C 24 C  Mean over phosphate carriers  NH H P0  13.87  19.16  5.51  ab  Ca(H P0 ) H 0  15.61  21.95  6.26  a  CaHPO 4  13.95  20.46  5.74  ab  14.79  21.28  6.01  ab  5.41  b  4  2  4  2  4  Ca(P0 ) 3  Ca  10  (P0  2  2  2  4>6  (GH  2"  Mean over s o i l temperatures  12.72  4.73 a  19.74 6.84 b  Any two means not having l e t t e r s i n common are s i g n i f i c a n t l y different at the 5 per cent l e v e l by the Duncan test.  Any two means with the same l e t t e r are not s i g n i f i c a n t l y d i f f e r e n t .  Table 15.  Y i e l d of a l f a l f a at two s o i l temperatures 1°C and 24°C i n N i s c o n l i t h clay loam treated with phosphate c a r r i e r s of different water s o l u b i l i t y  Phosphate carriers (applied at a rate equivalent to 120 lb P 0 per acre)  Yields of 3 cuttings -gm oven dry material per got at two s o i l temperatures - C 10°C 24°C  Mean over phosphate carriers  NH H P0  22.14  28.47  8.43  ab  Ca(H2P04)2H 0  22.27  27.34  8.27  a  CaHP0  23.02  27.30  8.39  a  24.25  30.72  9.16  ab  26.04  30.81  9.48  b  7.85 a  9.64 b  2  5  4  2  4  2  4  Ca(P0 ) 3  C a  10  ( P O  2  4 6 )  ( 0 H )  2  Mean over s o i l temperatures  Any two means not having l e t t e r s i n common are s i g n i f i c a n t l y d i f f e r e n t at the 5 per cent l e v e l by the Duncan test.  Any two means with the same l e t t e r are not s i g n i f i c a n t l y d i f f e r e n t .  55  2•, Results and Discussion (a) Y i e l d Analysis of variance of the y i e l d s from the Machete and N i s c o n l i t h s o i l (see Appendices 13 and 16) showed that temperature was s i g n i f i c a n t at P r 0.01 for both s o i l s while the e f f e c t of phosphorus source was s i g n i f i c a n t at P  :  0.20 on the Machete s o i l and P s 0.10  on the N i s c o n l i t h . A comparison of y i e l d s means i n table 14 showed that at 24°C s i g n i f i c a n t l y higher y i e l d s were obtained than at 10°C.  The  same r e s u l t was obtained on the N i s c o n l i t h s o i l as i l l u s t r a t e d i n table 15.  On the Machete s o i l monocalcium phosphate was responsible f o r  producing  s i g n i f i c a n t l y greater y i e l d s than hydroxyapatite, while on  the N i s c o n l i t h s o i l hydroxyapatite  caused s i g n i f i c a n t l y greater yields  than monocalcium phosphate and calcium metaphosphate. Many workers have reported the effects of temperature on plant growth and the general opinion i s that increasing temperatures, up to a point which i s optimum for the p a r t i c u l a r plant, w i l l cause increased growth i f a l l other factors are favourable.  Parups et a l  (42) and ( 4 3 ) , have reported that increasing s o i l temperatures up to o 30 C increased the o v e r a l l growth of tobacco while temperatures below 14°C decreased  the plant growth.  Nielson et a l (40) working with  oats showed that higher yields of straw and grain were produced when the s o i l temperature increased from 41°F to 67°F.  Robinson (50) also  reported an increase i n growth up to 80°F with red clover. When growth i s r e l a t e d to temperature the factors to be considered are many and i t i s believed that the e f f e c t i s mainly physiological.  Here,  i t was observed that the plant root growth of a l f a l f a at 10°C was d e f i n i t e l y poorer than at 24°C. According to Richards et a l (49): "growth i s a complicated summation of a number of individual processes, each of which also i s affected by temperature."  Some of the factors affected by temperature  are: v i s c o s i t y of water, mobility of cations and mineralization of nitrogen, sulphur, phosphorus and other elements. (b) Phosphorus content Phosphorus content of the a l f a l f a tissue harvested from both the Machete and N i s c o n l i t h s o i l s (tables 16 and 17) showed that at o o 24 C the phosphorus uptake was s i g n i f i c a n t l y greater than at 10 C. Phosphorus sources had l i t t l e or no e f f e c t on the phosphorus content i n the plant tissue.  I t seems from these r e s u l t s that the temperatures  used i n t h i s experiment had similar effects on a l l the phosphate sources used.  57  Figure 10.  The e f f e c t of s o i l temperatures and phosphate f e r t i l i z e r s on the y i e l d of a l f a l f a grown on the Machete stony sandy loam and the N i s c o n l i t h clay loam.  Table 16.  Phosphorus content i n a l f a l f a at two s o i l temperatures 10°C and 24°C in Machete stony sandy loam treated with f i v e phosphate c a r r i e r s of different water s o l u b i l i t y .  Phosphate carriers (applied at a rate equivalent to 120 lb PgOj per acre)  Phosphorus content of 3 cuttings - per cent at two s o i l temperatures. -°C 10°C 24°C  Means over phosphate carriers  NH H P0  .561  .608  .195  ab  Ca(H P0 ) H 0  .568  .583  .192  ab  CaHPO. 4  .563  .639  .200  a  .573  .586  .193  ab  .483  .591  .179  b  .183 a  .200 b  4  2  4  2  4  Ca(P0 ) 3  2  2  2  Ca (PO ) (OH) 10  4  6  2  Means over s o i l temperatures  Any two means not having l e t t e r s i n common are s i g n i f i c a n t l y d i f f e r e n t at the 5 per cent l e v e l by the Duncan test.  Any two means with the same l e t t e r are not s i g n i f i c a n t l y d i f f e r e n t .  Table 17.  Phosphorus content i n a l f a l f a at two s o i l temperatures 40 C and 24 C in Nisconlith clay loam treated with f i v e phosphate c a r r i e r s of different water s o l u b i l i t y .  Phosphate carriers (applied at a rate equivalent to 120 lb per acre)  Phosphorus content of 3 cuttings - per cent Q at two s o i l temperatures - C  Means over phosphate carriers  10°C  24°C  .515  .641  .193  a  Ca(H2P04) H 0  .486  .658  .191  a  CaHP0  .586  .586  .195  a  .566  .623  .198  a  .509  .538  .175  a  ,177 a  .203 b  NH H P0 4  2  4  2  2  4  Ga(P0 ) 3  2  Ca (PO ) (OH) 10  4  6  2  Means over s o i l temperatures  Any two means not having l e t t e r s i n common are s i g n i f i c a n t l y d i f f e r e n t at the 5 per cent l e v e l by the Duncan test.  Any two means with the same l e t t e r are not s i g n i f i c a n t l y d i f f e r e n t .  60  0.22,24 C.»-  u > < O 0.20> <  MACHETE  S.E.  u. 0.18 • <  <r o i a to o i a  I0"C. NISCONLITHT  0.16-  a: tu 0.14 a.  I S.E.  NH H P0« 4  2  Ca(H P0 ) .H 0 2  4  2  SOURCE  Figure 11.  CaHP0  2  OF  _L  4  Ca(P0 ) 3  2  Ca, (P0 ) (0H) 0  4  PHOSPHORUS  The e f f e c t of s o i l temperatures and phosphate f e r t i l i z e r s on the per cent phosphorus i n a l f a l f a tissue on the Machete stony sandy loam and the N i s c o n l i t h clay loam.  6  2  Table 18.  Phosphorus uptake by a l f a l f a at two s o i l temperatures, 10°C and 24 C in Machete stony sandy loam treated with f i v e phosphate c a r r i e r s of different water s o l u b i l i t y .  Phsophate carriers (applied at a rate equivalent to 120 lb P2O5 per acre)  Phosphorus uptake of 3 cuttings -gm x 10" per pot at two s o i l. temperatures - C 24°C 10°C  NH H P0  2.587  3.879  1.078  b  Ca(H P0 ) H 0  2.968  4.258  1.204  a  CaHPO. 4  2.641  4.351  1.165  ab  2.798  4.177  1.162  ab  2.062  3.885  .991  b ,  .870 a  1.370 b  4  2  4  2  4  Ca(P0 ) 3  C a  2  2  2  10< 4>6< £ P 0  O H  Mean over s o i l temperatures  Mean over phosphate carriers  •  '  •  Any two means not having l e t t e r s i n common are s i g n i f i c a n t l y d i f f e r e n t at the 5 per cent l e v e l by the Duncan test.  Any two means with the same l e t t e r are not s i g n i f i c a n t l y d i f f e r e n t .  Table 19.  Phosphorus uptake by a l f a l f a at two s o i l temperatures, 10°C and 24°C i n Nisconlith clay loam treated with f i v e phosphate c a r r i e r s of different water s o l u b i l i t y .  Phosphate carriers (applied at a rate equivalent to 120 lb P2O5 per acre)  Phosphorus uptake of 3 cuttings -gm x 10" per pot at two s o i l temperatures - C 10°C 24°C  Means over phosphate carriers  NH H P0  3.805  6.081  1.648  a  Ca(H P^) H 0  3.653  6.022  1.613  a  CaHPO. 4  4.538  5.365  1.651  a  4.613  6.442  1.843  a  (PO ) (OH) 4 6 2  4.468  5.567  1.673  a  Means over s o i l temperatures  1.405 a  1.965 b  4  2  4  2  2  Ca(P0 ) 3  Ga  10  2  2  Any two means not having l e t t e r s i n common are s i g n i f i c a n t l y different at the 5 per cent l e v e l by the Duncan test.  Any two means with the same l e t t e r are not s i g n i f i c a n t l y  different.  63  Figure 12.  The e f f e c t of s o i l temperatures and phosphate f e r t i l i z e r s on the uptake of phosphorus on the Machete stony sandy loam and the N i s c o n l i t h clay loam.  Table 20.  NaHCO^ extractable phosphorus remaining i n the Machete stony sandy loam at the end of the 1st a l f a l f a cutting.  Phosphate c a r r i e r (applied at a rate equivalent to 120 lb P 0 per acre)  Phosphorus content of 4 replicates -ppm at two s o i l temperatures - C 10°C  24°C  Means over phosphate carriers  NH H P0  108  90  24.75  a  Ca(H P0 ) H 0  86  178  33.00  b  CaHPO. 4  98  90  23.50  a  104  90  24.25  a  62  66  16.00  c  2  5  4  2  4  2  4  Ca(P0 ) 3  2  2  2  Ca (PO ) (0H) 10  4  6  2  Means over s o i l temperatures  22.90 a  25.70 b  Any two means not having l e t t e r s i n common are s i g n i f i c a n t l y d i f f e r e n t at the 5 per cent l e v e l by the Duncan test.  Any two means with the same l e t t e r are not s i g n i f i c a n t l y d i f f e r e n t .  Table 21.  NaHCO extractable phosphorus remaining i n the N i s c o n l i t h loam at the end of the 1st a l f a l f a cutting.•  clay  Phosphate carriers (applied at a rate equivalent to 120 lb P 0 per acre)  Phosphorus content of 4 replicates -ppm at two s o i l temperatures - C 10°C  24°C  NH H P0  188  264  56.50  a  Ca(H P0 ) H 0  208  224  54.00  a  CaHPO, 4  126  148  34.25  b  162  162  40.50  b  124  142  33.25  b  40.40 a  47.00 b  2  5  4  2  2  4  Ca(P0 ) 3  C a  10  4  ( P O  2  2  4>6  ( O H )  2  Means over s o i l temperatures  Mean over phosphate carriers  Any two means not having l e t t e r s i n common s i g n i f i c a n t l y different at the 5 per cent l e v e l by the Duncan test.  Any two means with the same l e t t e r are not s i g n f i c a n t l y  different.  66 (b) Phosphorus content  (continued)  Barber (35) reported an increase i n phosphorus a v a i l a b i l i t y when s o i l s o o were incubated at -20.5 G as compared with 27 C.  An increase i n the  a v a i l a b i l i t y of phosphorus with increasing temperatures s i t u a t i o n according to Mack and Barber (35).  i s the normal  They believed that rate of  solution of phosphorus i s dependent on the rate constant and surface area of phosphorus compounds present, the rate constant being affected by temperature and a c t i v i a t i o n energy according to the Arrhenius equation: k - Ae where E  -E  a  /RT  i s the a c t i v a t i o n energy, A i s the constant, R i s the gas Si  constant and T the absolute temperature.  The reason for the increase  i n phosphorus at such a low temperature i s believed to be due to the formation of new phosphorus compounds and a change i n the a c t i v a t i o n energy of the phosphorus compounds.  Robinson (50) believes that the  more rapid uptake of phosphorus at higher temperatures  i s associated  with the temperature c o e f f i c i e n t of absorption rather than with an increase i n phosphorus concentrations i n s o i l solutions.  The  latter  theory seems the most l i k e l y i n t h i s experiment since no p a r t i c u l a r phosphate source had any s i g n i f i c a n t e f f e c t . (c) Uptake of phosphorus The y i e l d of phosphorus from the Machete and N i s c o n l i t h s o i l s are given i n tables 18 and 19 and the graphical presentation on figure 12.  A comparison of the phosphorus y i e l d means showed that  s i g n i f i c a n t differences among phosphorus sources existed between monocalcium phosphate and hydroxyapatite and between monocalcium phosphate and monoammonium phosphate on the Machete s o i l .  The y i e l d of phosphorus  from the N i s c o n l i t h s o i l was not s i g n i f i c a n t l y affected by the phosphate  67 source.  Temperature e f f e c t was s i g n i f i c a n t i n increasing the y i e l d of  phosphorus on both s o i l s . (d) NaHCO^ extractable phosphorus  An analysis of variance on the NaHCO^ extractable phosphorus data, Appendix 14, showed the e f f e c t of phosphorus source, and the Interaction of phosphorus and temperature to be s i g n i f i c a n t on the Machete s o i l .  Variance analysis on the NaHCG^ extractable data from  the N i s c o n l i t h s o i l , table 16, also showed that the e f f e c t of phosphorus source was s i g n i f i c a n t i n the production of extractable phosphorus. A comparison of phosphorus means i n table 20 showed that at 24°C the NaHCO^ extractable phosphorus was s i g n i f i c a n t l y greater than at 10°C.  A comparison of the means also showed that s i g n i f i c a n t  differences occurred between the e f f e c t s of monocalcium phosphate and a l l the sources of phosphorus. The N i s c o n l i t h clay loam at 24°C gave a s i g n i f i c a n t l y greater amount of extractable phosphorus than at 10°C as i l l u s t r a t e d on table 21. For t h i s s o i l also monoammonium phosphate and monocalcium phosphate greatly affected the extractable phosphorus as compared to the other sources of phosphorus.  68  —' 70 2 4  C«s  UJ  60  CL  NISCONLITH  EC <  I S.E  50  CL I  ist 3  o  1 o  4 0  i  CL  w 30 _j CD < rO  < rr 20 tx  UJ  o o I  MACHETE  ]s.E.  10  NH H P0 4  2  4  C (H P0 ) .H 0 a  2  4  2  SOURCE  Figure 13.  C HP0  2  OF  a  4  Ca(P0 ) 3  2  Ca| (P0 ) (0H)  PHOSPHORUS  The effect of s o i l temperatures and phosphate f e r t i l i z e r s on 05N.NaHCO extractable phosphorus from Machete stony sandy loam and N i s c o n l i t h clay loam. 3  0  4  6  z  69 (d) NaHCG  extractable phosphorus (continued)  Removal of phosphorus by NaHCO^ seems to be d i r e c t l y r e l a t e d to the water s o l u b i l i t y of these phosphate compounds.  In the Machete  s o i l , the trend i s f o r the more soluble compounds to release more NaHCO^ extractable phosphorus.  I t w i l l be noticed that the e f f e c t s  of monocalcium phosphate was responsible for s i g n i f i c a n t l y greater amounts of phosphorus than monoammonium phosphate although the l a t t e r compound i s about 40 times more water soluble.  I t i s believed that because  of i t s high water s o l u b i l i t y monoammonium phosphate moved more than the monocalcium phosphate d i d and thus the rate of i t s phosphorus removal from the s o i l must have been greater.  Since time also plays  an important part i n phosphorus recovery a f t e r i t has been added i n the form of f e r t i l i z e r , monoammonium phosphate might have given higher r e s u l t s had the NaHCO^ extractable phosphorus had been determined e a r l i e r on i n the experiment.  For the N i s c o n l i t h s o i l , the phosphate  sources affected the extractable phosphorus according to the degree of t h e i r water s o l u b i l i t y . In tables 20 and 21 a trend toward increased NaHCO^ extractable phosphorus with increased temperature i s i l l u s t r a t e d .  This might be due  to b a c t e r i a l a c t i v i t y since, according to Thompson (61), at 24°C mineralization of organic phosphorus would be greater than at 10°C. Although i t was not established i n this experiment there might have been also d i s s o l u t i o n of the phosphate f e r t i l i z e r s through b a c t e r i a l action as reported by Louw and Webley (33).  70 SUMMARY AND CONCLUSION  The effects of four s o i l moisture tension ranges, 0.2-0.4, 0.20.8, 0.2-2.0, and 0.2-6.0 bars, on the a v a i l a b i l i t y of phosphorus i n two calcareous s o i l s Machete stony sandy loam and N i s c o n l i t h clay loam were studied.  I t was found that d i f f e r e n t ranges of s o i l moisture  tension s i g n i f i c a n t l y affected the growth of a l f a l f a .  On both s o i l s ,  the highest yields of a l f a l f a forage were obtained when the moisture tension was held i n the range 0.2-2.0 bars.  The y i e l d s i n the ranges  0.2-0.4, 0.2-2.0 and 0.2-6.0 bars were considerably l e s s .  The r e s u l t s  also showed that the s o i l moisture tension range which gave the maximum y i e l d s , was most favourable for the uptake of phosphorus from both s o i l s . The effect of f i v e d i f f e r e n t phosphate sources (monoammonium phosphate, monocalcium phosphate, anhydrous dicalcium phosphate, calcium metaphosphate and hydroxyapatite) on the y i e l d of a l f a l f a proved to be of h e s i g n i f i c a n c e at the moisture tension levels used.  However, a v a i l a b i l i t y  of phosphate as indicated by the phosphate content of the plants was s i g n i f i c a n t l y d i f f e r e n t when the f i v e sources of phosphate were compared. The more available sources were monoammonium phosphate,, anhydrous dicalcium phosphate and monocalcium phosphate i n that order on the Machete s o i l and monocalcium phosphate, monoammonium phosphate and anhydrous dicalcium phosphate on the N i s c o n l i t h s o i l .  Since the a v a i l a -  b i l i t y of phosphate from the various sources showed s i g n i f i c a n t differences when compared yet the phosphate sources i n turn had no s i g n i f i c a n t effect on y i e l d , i t may be concluded that the amount of phosphate given up by a l l sources together with the moderately high content of available phosphate i n the two s o i l s (30 ppm and 40 ppm) was adequate for the crop  71  i n a l l cases.  Under these circumstances the factor a f f e c t i n g y i e l d  was found to be s o i l moisture tension.  Hence i f the s u i t a b i l i t y of  phosphate materials were being investigated i n the tension range 0.2-2.0 bars, optimum y i e l d would be found and l i t t l e or no difference would be observed among the sources of phosphate.  I f the s u i t a b i l i t y of  phosphate materials were being investigated at the other tension ranges of 0.2-0.4, 0.2-0.8 and 0.2-6.0 bars, lower y i e l d s would be obtained but t h i s would not be due to the phosphate sources. I t was also found that s o i l moisture tension had a greater influence on phosphate a v a i l a b i l i t y (as indicated by phosphate content from plants) from monoammonium phosphate and monocalcium phosphate than on phosphate a v a i l a b i l i t y from anhydrous dicalcium phosphate on the Machete s o i l .  Phosphate a v a i l a b i l i t y from hydroxyapatite and dicalcium  phosphate was l i t t l e influenced by moisture tension on the N i s c o n l i t h s o i l . I t was observed that after the f i r s t cutting of a l f a l f a , s o i l moisture tension had no e f f e c t on the amount of NaHCO^ extractable phosphorus present i n the s o i l following the f i r s t cutting of a l f a l f a . At the r e l a t i v e l y low rates of phosphate application used, measurements of dicalcium phosphate a c t i v i t y i n the s o i l was found to be unsuitable for predicting the a v a i l a b i l i t y of phosphorus from  phosphate  compounds. The two calcareous s o i l s did not behave similar i n a l l respects.  One of the reasons might be due to the higher clay content  i n the N i s c o n l i t h s o i l . In the study of the effects of two s o i l temperatures 10°C and 24°C, on phosphorus a v a i l a b i l i t y , i t was found that temperature affected growth s i g n i f i c a n t l y .  Higher y i e l d s of a l f a l f a were obtained at 24°C than  at 10°C on both s o i l s . An increase i n phosphorus content i n plant tissue with increased temperature was observed on both s o i l s .  There was no •  marked difference i n the a v a i l a b i l i t y of phosphate from the f i v e compounds at the two temperatures studied.  This indicates that at  any one temperature, the effects of the phosphate sources were similar. I t was found that following the f i r s t cutting, there was trend towards an increase i n NaHCO^ extractable phosphorus present i n the s o i l at the higher s o i l temperature.  73 APPENDIX L MACHETE - YIELD OF ALFALFA - MOISTURE z  4214.6033 - 4064.4678  :  4125.82 - 4064.46  r  4088.51 - 4064.46 = 24.05  s•s•  =  4078.23 - 4064.46  s.s.  =  4108.74 - (4064.46 + 24.05+  =  4108.74 - 4102.28  =  6.46  =  150.14 - (61.36 424.05 +13.77 + 6.46)  =  150.14 - 105.64  =  44.50  s.s.  z  150.14  Total s.s.  =  61.36  Rep s•s•  M.T. =  13.77 13.77)  M.T. x P  s.s.  error  Source  d.f.  s.s.  M.S.  F  F  F  F  F  207.  107.  57.  17.  rep  2  61.36  M.T.  3  24.05  8.01  6.84  1.62  2.23  2.85  4.34  P  4  13.77  3.44  2.94  1.57  2.09  2.62  3.86  M.T. x P  12  6.46  0.53  0.45  1.41  1.71  2.02  2.69  error  38  44.50  1.17  59  74  APPENDIX I I MACHETE - PER CENT P IN ALFALFA TISSUE - MOISTURE 2.3153 - 2.2651  S.6.  Total  r  0.0502  2.2675 - 2.2651 = 0.0024  s.s.  Rep >•s• M.T. s.s.  2.2778 - 2.2651  s.s.  2.2903 - (2.2651+ 0.0011+ 0.0127)  2.2662 - 2.2651 = 0.0011 :  0.0127  M.T. x P 2.2903 - 2.2789 0.0114 0.0502 - 0.0276  s.s. error  Source  0.0226  d.f.  s.s.  M.S.  F  F 20%  F 10%  F 5%  F 1%  rep  2  .0024  .0012  M.T.  3  .0011  .00336 0.610  1.62  2.23  2.85  4.34  P  4  .0127  .003175 5.38  1.57  2.09  2.62  3.86  M.T. x P  12  .0114  .00095 1.61  1.41  1.71  2.02  2.69  Error  38  .0226  .00059  Total  59  75 APPENDIX I I I MACHETE • UPTAKE OF P (gm. PER POT x 10~2) - MOISTURE s.s.  -160.3587 - 152.469 - 7.889 Total  s.s.  - 154.025 - 152.469 - 1.556 Rep  s.s.  - 153.707 - 152.469 - 1.238 M.T.  s.s.  - 153.918 - 152.469 « 1.449 P  s.s.  » 155.724 - (152.469 4- 1.238 + 1.449) M.T. x P = 155.724 - 155.156 - 0.568  s.s.  - 7.889 - (1.556 + 1.238 + 1.449 + 0.568) Error - 7.889 - 4.811 - 3.078 = 3.078  Source  d.f.  s.s.  M.S.  F. _  F 20%  F  F  F  10%  5%  1%  Rep  2  1.556  0.778  M.T.  3  1.238  0.4126  5.09  1.62  2.23  2.85  4.34  P  4  1.449  6.3622  4.46  1.57  2.09  2.62  3.86  M.T. x P  12  0.568  0.047  0.58  1.41  1.71  2.02  2.69  Error  38  3.078  0.081  59  76 APPENDIX IV MACHETE - NaHCO- SOLUBLE P - MOISTURE •'  1  a  27364.0  -  17819.2 - 9544.8  «  17933.8  -  17819.2 - 114.6  M.S. - 57.30  a  18329.3  -  17819.2 - 510.1  M.S. - 170.03  »  19106.3  -  17819.2 - 1287.1 M.S. » 321.77  a  21382.6 • (17819.2 + 510.1 + 1287. 1)  a  21382.6  Total Rep >•  M.T.  i•  rTO >•  Iff  X  P  . a  (19616.4)  1766.2  M.S. » 147.18  5866.8  M.S. « 154.38  error M.S.  F  Source  d.f.  8.8.  Rep  2  114.6  57.30  0.37  M.T.  3  510.1  170.03  1.10  P  4  1287.1  321.77  M.T. x P  12  1766.2  147.18  Error  38  5866.8  154.38  1)"™""""**  F  F 207.  F  F  10%  57.  17.  1.62  2.23  2.85  4.34  2.09  1.57  2.09  2.62  3.86  0.95  1.41  1.71  2.02  2.69  77 APPENDIX V MACHETE - pCaHPG. ACTIVITIES - MOISTURE  » 4316.95 - 4309.87 - 7.08  8*8*  Total - 4310.02 - 4309.87 - 0.15  s.s. Rep 8 •S •  M.T. s.s. P s.s. M.T. x P s.s. . error  '"- 4310.38 - 4309.87 « 0;51 -• 4311.53 - 4309.87 - 1.66 - 4313.00 - (4309.87 + 0.51 + 1.66) » 4313.00 - 4312.04 - 0.96 - 7.08 - (0.15 + 0.51 + 1.66 + 0.96) * 3.80  Source  d.f.  s.s.  Rep  2  0.15  M.T.  3  P  M.S.  F  F  F  F  F  20%  10%  5%  1%  0.7  0.51  .07 i .17  1.7  1.62  2.23  2.85  4.34  4  1.66  .41  4.1  1.57  2.09  2.62  3.86  M.T. x P  12  0.96  .08  0.8  1.41  1.71  2.02  2.69  Error  38  3.80  .10  78 APPENDIX VI MACHETE - MOISTURE A.  Y i e l d of a l f a l f a S.E. = f.rT7l7 mean-M.T. 15 V is  - VJ9780  - 0.279  S.E. mean-P  » /1.17 * 12  S.E. mean-M.T.xP B.  «  /TTl7  Per cent P i n a l f a l f a  S.E. mean-M.T.  - /.097?  -0.312  « /5t3900  » 0.625  N  tissue  . - /.00059 - J.000039 = .006244 * 15 V  S.E. mean-P S.E. mean-M.T.xP C.  »  /.00059 - J. 000049 » .007 V i2  . • j .00059  _____ » ^.'000196 » 0.014  Uptake of P (gm per pot x 10~ ) 2  S.E. mean-M.T.  « /T08l 15  - /00540  - 0.07348  >  S.E.  _  mean-P  » /T081  mean-M.T. x P  • /.081 y3  S.E.  » J.00675  « 0.0822  » /02700  « 0.1643  D. NaHC0 Soluble P 3  S.E. mean-M.T.  > /154.38 ^ 15  - V. 10.2920 - 3.21  79 APPENDIX VI (continued) MACHETE - MOISTURE S E. ' mean -P  = /154738 V 15  « JlO.2920  = ^/154.38 = / 3  » ^51.46  -  3.21  S  S.E. mean-M.T. x P E.  p CaHPO^ a c t i v i t i e s  S.E.  . »./.00666  -  .081  - /7l(f  - 7.00833  -  .091  - /7l0 *3  - J70333  • .182  mean-M.T.  - /TlQ V15  mean-P  mean-M.T. x P  S.E.  S.E.  - 7.16  'IT  v  N  80 APPENDIX VII NISCONLITH CLAY LOAM - YIELD OF ALFALFA - MOISTURE s.s.  - 6716126 - 6525.42 » 190.84 total  s.s.  « 6540.92 - 6525.42 » 15.50 rep  s.s.  » 6565.65 - 6525.42 - 40.23 M.T.  s.s.  - 6534.31 - 6525.42 » 8.89 P  s.s.  - 6638.53 - (6525.42 + 40.23 + 8.89) M.T. x P - 6638.53 - 6574.54 - 63.99  s.s. - •Error  - 190.84 - (15.50 + 40.23 + 8.89 + 63.99) - 190.84 - 128.61 - 62.23  M.S.  F  40.23  13.41  4  8.89  M.T. x P  12  Error  38 59  Source  d.f.  s.s.  Rep  2  15.50  M.T.  3  P  F  F  F  F  20%  10%  5%  8.22  1.62  2.23  2.85  2.22  1.32  1.57  2.09  2.62  63.99  5.33  3.27  1.41  1.71  2.02  62.23  1.63  1%  81 APPENDIX VIII NISCONLITH CLAY LOAM - PER CENT P IN ALFALFA - MOISTURE  s•s•  2.9686 - 2.7928 - 0.1758  total a  8.S.  2.9267 - 2.7928 - 0.1339  Rep s.s. . M.T.  2.7983 - 2.7928 - 0.0055  S.8.  2.7958 - 2.7928 a . 0030 P  S.S.  m  2.8087 - (2.7928 + .0055 + .0030)  M.T. x P 2.8087 - 2.8013  S •  8•  m  0.0074  a  0.1758 T 0.1339 + 0.0055 + 0.0030 + 0.0074  a  0.1758 - 0.1498  error  -  0.0260  F  Source  d.,f.  s.s.  M.S.  Rep  2  .1339  0.0669  M.T.  3  .0055  0.0018  P  4  .0030  0.00075  M.T. xP  12  .0074  0.000616 0.905  Error  38 59  .0260  0.00068  F  F  F  F  207.  10%  5%  1%  2.64  1.62  2.23  2.85  4.34  2.0?  1.57  2.09  2.62  3.86  1.41  1.71  2.02  2.69  82  APPENDIX IX _2 NISCONLITH CLAY LOAM r UPTAKE OF P (9m. PER POT x 10 ) - MOISTURE s.s.  -345.166.- 309.900 -35.266 total  s.s.  - 330.897- 309.900 -20.997 Rep  s.s.  - 312.908-- 309.900 « 3.008 m.T.  s.a.  - 310.7229 - 309.900 • 0.822 P  s.s.  - 317.056 - (309.900 + 3.008 + .822) M.T. x P -317.056 - 313.730 - 3.326 » 3.326 » 35.266 - (20.997 + 3.008 + 0.822 + 3.326)  s.s. Error  « 35.266 -- 28.153 - 7.113  Source  d.f.  s.s.  M.S.  F  F  F  20%  10%  F  F  5%  1%  Rep  2  20.997  10.498  M.T.  3  3.008  1.0026  5.358  1.62  2.23  2.85  4.34  P  4  0.822  0.205  1.095  1.57  2.09  2.62  3.86  0.2771 0.1871  1.481  1.41  1.71  2.02  2.69  M.T. x P Error  12 30 59  3.326 7.113  83 APPENDIX X NISCONLITH CLAY LOAM - NaHCOg SOLUBLE P - MOISTURE » 125936 - 110768 » 15168  8*8*  total » 111985.70 - 110768.0 - 1217.7  8.8.  Rep  s.s.  - 110875.3 - 110768.0 - 107.3 M.T. - 113222.1 - U0768.0 - 2454.1  8.8.  » 115582 - (110768 + 107.3 + 2454.1)  8*84  M.T. x P  8.8.  - 2252.6 = 15168 - (1217.7 + 107.3 + 2252.6 + 2454.1)  Error » 9136.3  Source  d.f.  s.s.  M.S.  Rep  2  1217.7  608.85  M.T.  3  107.3  35.76  P  4  2454.1  613.52  M.T. x P  12  2252.6  187.71  Error  38  9136.3  240.42  F 20%  10%  5%  1%  1.62  2.23  2.85  4.34  2.55  1.57  2.09  2.62  3.86  0.78  1.41  1.71  2.02  2.69  2.53 .148  84 APPENDIX XI NISCONLITH pCaHPO^ ACTIVITIES - MOISTURE  s.s.  - 3567.84 - 3564.95 - 2.89 Total  s.s.  » 3565.06 - 3564.95 =0.11 Rep  s.s. • M.T. s.s. . P s.s. M.T. x P  « 3565.09 - 3564.95 - 0.14 - 3565.34 - 3564.95 - 0.39 » 3565.78 - (3564.95 + 0.14 + 0.39) - 3565.78 - 3565.48 -  s.s.  0.30  » 2.89 - ( O i l + 0.14 + 0.39 + 0.30) error » 2.89 - 0.94 - 1.95  Source  d.f.  s.s.  M.S.  F  F  F  F  20%  10%  F  5%  1%  Rep  2  0.11  0.055  1.078  M.T.  3  0.14  0.046  .901  1.62  2.23  2.85  4.34  P  4  0.39  0.097  1.901  1.57  2.09  2.62  3.86  M.T. x P  12  0.30  0.025  .490  1.41  1.71  2.02  2.69  Error  38  1.95  0.051  85 APPENDIX XII NISCONLITH CLAY LOAM - MOISTURE A.  Y i e l d of A l f a l f a (gm per  pot)  S.E. mean-M.T. S.E. mean-P  - /I763  1.62 /12  0.1086  - 0.330  '- /.1358  - 0.368  » ,0.5433  - 0.747  S.E. mean-M.T. x P - '1.63  V3  B. Per cent P i n A l f a l f a S.E. mean-M.T.  "Jo.00068  =yi0.000045  « 0.006708  mean-P  »/o\c 00068 il2  »/0.000056  » 0.007483  mean-M.T. x P -/0_.00068  -/0.000226  - 0.0153  S.E.  S.E.  3  C.  Uptake of P (gm. per pot x IO" ) 2  S.E. mean-M.T.  - ^7J871  » 01247 v  - 0.1118  mean-P  -/0.1871 12  -A).01559  - 0.1249  -/0.1871  »/0.06236  S.E.  S.E. mean-M.T. x P  - 0.2500  APPENDIX XII (continued) NISCONLITH CLAY LOAM - MOISTURE D.  NaHC0 soluble P 3  S.E. mean-M.T.  S.E. mean-P  f  «/240.42 15  »yi6.028  -/240.42 °/240. 412.  «/20.035  S.E. mean-M.T. x P "/240.42 3 E. pCaHPO^  »/80.140  activities  S.E. mean-M.T.  • /.051  »/.0034  S.E. mean-P  - /.051  »/.00425  S.E. ^ mean-M.T. x P »/To51 I3  - /.017  87 APPENDIX XIII MACHETE - YIELD OF ALFALFA gm PER POT - TEMPERATURE  CF.  s.s.  » 30.112.6609 30 Total  s.s. . Rep  - 1,003.7553  « 1,049.3649 - C F . «, 45.61 - 10.048.3121 - 1,003.75 - 1.08 10  s.s. Temp s.s.  - 1,037.1461 - 1,003.75 - 33.39 - 1,006.74 - 1,003.75 - 2.99  P s.s;  - 1,040.4065 - (1,003.75 + 33.39 + 2.99) T x P 1,040.4065 - 1,040.13 - 0.27  s.s.  - 45.61 - (1.08 + 33.39 + 2.99 + 0.27) error - 45.61 - 37.73 * 7.88  Source  d.f.  s.s.  M.S.  F .  F  F  20%  10%  F  F  5%  1%  Rep  2  1.08  0.54  P  4  2.99  0.7475  1.707  1.67  2.29  2.93  4.58  T  1  33.39  33.39  76.28  1.77  3.01  4.01  8.28  4 _18 29  0.27 7.88  0.065 0.4377  P x T Error  .1  88 APPENDIX XIV MACHETE - NaHC0 SOLUBLE P - TEMPERATURE 3  s.s.  - 26,760 - 23,619.6 = 3,140.4 Total  s.s.  - 23,732 - 23,619.6 » 112.4 Rep  s.s. .P s.s. T s.s. P x T  - 24,783 - 23,619.6 » 1,163.4 » 23,698 - 23,619.6 - 78.4 - 25,916 - (23,619.6 + 1,163.4 +78.4) - 25,916 - 24,861.4 - 1054.6 « 3,140.4 (112.4 + 1,163.4 + 78.4 + 1,054.6)  Error » 3,140.4 - 2,408.8 - 731.6  F 10%  F 5%  1%  1.61  2.17  2.73  4.11  2.89  1.73  2.90  4.21  7.68  9.73  1.61  2.17  2.73  4.11  F  F  290.85  10.73  78.4  1,054.6  263.65  731.6  27.09  Source  d. f.  Rep  3  112.4  37.46  P  4  1,163.4  T  1  78.4  P x T  4  Error  27  s.s.  t - 1.314 1.7-3 2.052 2.771  M.S.  207. 10% 5% 1%  20%  F  89 APPENDIX XV NISCONLITH CLAY LOAM - YIELD OF ALFALFA - TEMPERATURE s.s.  » 2,364.6708 - 2,294.42 • 70.25 total  s.s.  » 2,320.764 - 2,294.42 - 26.34 Rep  s.s.  - 2,318.58 - 2,294.42 - 24.16 Temp  s.s.  - 2,301.37 - 2,294.42 - 6.95 P  s.s.  » 2,301.37 - (2,294.42 + 24416 + 6.95) T x P - 2,326.15 - 2,325.53 - 0.62  s.s.  - 70.25 - (26.34 + 24.16 + 6.95 + 0.62) Error « 70.25 - 58.07 - 12.18  Source  d.f.  s.s.  Rep  2  26.34  P  4  6.95  T  1  24.16  4 18 29  0.62 12.18  P x T Error  18 d.f.  = 1.33 1.734 2.101 2.878  M.S.  F  F  F  F  20%  10%  2,569  1.67  35.73  1.77  F  5%  1%  2.29  2.93  4.58  3.01  4.41  8.28  13.17 1.737 24.16 0.155 0.676 20% 10% 5% 1%  90 APPENDIX XVI NISCONLITH CLAY LOAM - NaHCO-j SOLUBLE - TEMPERATURE  s.s.  - 83,552 - 76,387.6 - 7,164.4 Total  s.s.  - 76,796 - 76,387.6 » 408.4 Rep  s.s.  - 80,217 - 76,387.6 - 3,829.4 P  s.s.  - 76,823.2 - 76,387.6 = 435.6 T  s.s  » 81,072 - (76,387.6 + 3,829.4 + 435.6) P x T 419.4  s.s.  - 7,164.4 - (3,829.4 + 408.4 + 435.6 + 419.4) Error - 7,164.4 - 5,092.8 - 2,071.6  F  F  957.3  12.40  1.61  435.6  435.6  5.28  4  419.4  104.8  27 39  2071.6  76.7  Source  d.f.  s.s.  M.S.  Rep  3  408.4  136.1  P  4  3829.4  T  1  P x T Error  1.36  20%  F  F  F 107.  57.  17,  2.17  2.73  4.11  1.73  2.90  4.21  7.68  1.61  2.17  2.73  4.1  91 APPENDIX XVII MACHETE - TEMPERATURE A.  Y i e l d of A l f a l f a (gm per pot)  S.E. mean-T  S.E. mean-P  S.E. mean-T x P  B.  0.4377 15  70.02918  « 0.171  (0.4377 6  07295  0.270  °»/6.4377  »/hl4590  • 0.382  a —  NaHC0 soluble P 3  S.E. mean - T  S.E. mean-P  S.E. mean-T x P  -/27.09 20  '1.354  1.162  /27.09 8  3.386  1.84  °/27.09 '/27.  = /6.772  2.60  92 APPENDIX XVIII MACHETE - PER CENT PHOSPHORUS - TEMPERATURE S.E. mean - T  _  »/oTo0024 r is  S.E. mean - P S.E. . mean - P x T  WO.00024  »/lM)0024 * 3  »/0.000016  - 4.0 x 10  . -^.00004  - 6.32 x 10  »/0.00008  « 8.94 x 10"  v  3  T  Machete - Phosphorus uptake (gm. per pot x 10" ) - Temperature z  mean - T S.E. mean - P S.E. mean - P x T  »/0.0274  » 0.0274 ^ 6  WO.0274  »/COOt82  » 4.24 x 10  _ = 0.00456  2 » 6.76 x 10"  V  »J0.00913  -2 - 9.56 x 10  93 APPENDIX XIX NISCONLITH CLAY LOAM - TEMPERATURE A.  Y i e l d of A l f a l f a (gm. per pot)  S.E. mean - T S.E. mean-P  - /oTo76  - /.0450  - 0.212  -/0.676  «/.1126  - 0.335  -yl =,0.2253  - 0.475  »/3.835  - 1.954  -/7oT7 N 20  =/9.587  » 3.10  =[76.7  »/25.566  » 5.05  4  S .E. mean - T x P B.  6  -/0.676 -Jo. 676  NaHC0 soluble P 3  S.E. mean -T  . S.E. mean -P S.E. mean T x P  -76.7  4 20  <  3  94 APPENDIX XX NISCONLITH CLAY LOAM - PER CENT PHOSPHORUS - TEMPERATURE S.E. mean - T  •»/0.00042 < 15  •3  »/0.000028 /  » 5.29 x 10  »/oTo0042  -^bTo0007  - 8.36 x I O  »j6To0042  -£00014  - 11.83 x 1 0 "  s  S E.  mean - P  - 3  S E mean-T x P  <  3  *  3  N i s c o n l i t h clay loam - Phosphorus uptake (gm per pot x 1 0 " ) - temperature 2  S.E. mean -T  S.E. mean - P  S.E. mean- T x P  .  -/0.033 >/ 15  »/670022  -/0.033  -/0.0055  —. -/0.033  - 4.69 x  10  v  _ —  »/57b11  - 7.41 x 10%-2 _2 » 10.48 x 10  95 BIBLIOGRAPHY 1.  Beater, B. E. 1937  2.  Beaton, J.D., and Nielsen, K. 1959 The a v a i l a b i l i t y to a l f a l f a of phosphorus from twelve different carriers Can.J. of S o i l S c i i 39: 54-63.  3.  Binet, F. E., L e s l i e , L e s l i e , R. T., Weiner, S., and Anderson, R.L. 1955 Analysis of confounded f a c t o r i a l experiments i n single r e p l i c a t i o n s . Reprint of North Carolina A g r i c u l t u r a l Experiment Station Technical B u l l e t i n No. 113.  4.  Bouldin, D. R., and Sample, E. C. 1958 The effect of associated s a l t s on the a v a i l a b i l i t y of concentrated superphosphate. S o i l S c i . Soc. Amer. Proc 22: 124-129  5. 1959  Measuremet of phosphate f i x a t i o n S o i l S c i . 44:277  in soil  Laboratory and greenhouse studies with monocalcium, monoammonium and dicalcium phosphate. S o i l S c i . Soc. Amer. Proc 23: 338-342  6.  Cheng, K. L. and Bray, R. H., 1951 Determination of calcium and magnesium i n s o i l and plant material. S o i l S c i 72: 449-458  7.  Clark, J.S., and Peech, M., 1955 S o l u b i l i t y c r i t e r i a for the existence of calcium and aluminium phosphate i n s o i l s . S o i l S c i . Soc. Amer. Proc. 19: 171-174.  8. 1955 9.  . 1955  S o l u b i l i t y c r i t e r i a for the existence of hydroxyapatite. Can. J . Chem. 33: 1696-1700 and Turner, R.C. Reactions between s o l i d calcium carbonate and orthophosphate solutions. Can. J . Chem 33: 665-671  10.  Cole, C. V., and Olsen, S. R. 1959 Phosphorus s o l u b i l i t y i n calcareous s o i l s ; (1) Dicalcium phosphate a c t i v i t i e s i n equilibrium solutions (2) E f f e c t s of exchangeable phosphorus and s o i l texture on phosphorus s o l u b i l i t y . S o i l S c i . Soc. Amer. Pro 23: 116-121.  11.  Collis-George, N. and Davey, B. G. 1960 The doubtful u t i l i t y of present-day f i e l d experimenta ion and other determinations involving s o i l - p l a n t interactions. S o i l s and F e r t i l i z e r s XXIII 307-310.  96 12.  Cooke, C. J . W., and Widdowson, F. V., 1959 F i e l d experiments on phosphate f e r t i l i z e r s a j o i n t investigation. J . A g r i . S c i . 53.  13.  Corgan, J . N., and Hibbard, A. D., 1960 The e f f e c t of moisture, stress on uptake and translocation of phosphorus i n Red Kidney beans. Plant Physiology 35: 4.  14.  Dickman, S. R., and Bray, R. H., 1940 Colorimetric determination of phosphate. Eng. Chem. And. Ed. 12: 665-668.  Ind and  15.  Duncan, D. B., 1955  16.  Egan, E. D. J r . , Wakefield, Z. T., and K e l l y , L. E. 1950 High temperature heat content of hydroxyapatite, J . Amer. Chem. Soc 72: 2418 - 2421.  17.  Fawcett, R. G., and Quirk, J . P., 1960 E f f e c t of water-stress on the absorption of s o i l phosphorus by wheat plants. Nature 188: 687-688.  18.  Ford, M. E., 1933  The nature of phosphate f i x a t i o n i n s o i l s . Amer. Soc. Agror. 25: 134  19.  H i l l , W. L., 1957  Phosphatic F e r t i l i z e r s : Chem 5: 96-101.  20.  Howe, D.O., and Graham, E. R., 1955 S a l t concentration i n the a v a i l a b i l i t y of phosphorus for rock phosphate as revealed by the growth and composition of a l f a l f a . S o i l Sco. Soc. Amer. Proc. 19: 315-319.  21.  Jackson, M.L., 1948  S o i l Chemical Analysis. Prentice H a l l pp 153.  22.  K e l l y , C. C , 1954  B r i e f 28 "Proceedings of the Reclamation Committee".  23. 1945  New multiple range test. Biometrics 11: 1-42  J.  Processing Agric and  B r i e f 2. "Recommendations of the Okanagan A g r i c u l t u r a l Club Committee on Post-War R e h a b i l i t a t i o n and Reclamation Problems".  24.  K e l l y , J . B., and Midgely, A. R., 1943 Phosphate f i x a t i o n - An exchange of phosphate and hydroxyl ions. S o i l S c i . 55:167.  25.  Kitson, R. E., and Mellon, A.C., 1944 Colorimetric determination of phosphorus as molybdovanado phosphoric acid. Anal. Chem. 16: 379-383.  97 26.  Klotz, I . M., 1950  27.  Lathwell, D.J., Cope, J.T., and Webb, J . R., 1960 L i q u i d f e r t i l i z e r s as sources of phosphorus for f i e l d crops. Agron. J . 52: 251-254.  28.  Lawton, K., Apostolakus, C , Cooke, R. L., and H u l l , W. L. 1956 Influence of p a r t i c l e size, water s o l u b i l i t y , and placement of f e r t i l i z e r on the nutrient values of phosphorus i n mixed f e r t i l i z e r s . S o i l S c i . 82: 465-476.  29.  Lehr, J . R., Brown, W. E., Brown, H. E., 1959 Chemical behavior of monocalcium phosphate monohydrate i n s o i l s . S o i l S c i . Soc. Amer Proc. :23 3-12.  30.  Linder, W. H., 1944  31.  Lindsay, W. L., and Standford, G., 1960 What happens to water-soluble phosphate i n the s o i l . Crops and S o i l s 12: No. 8.  32. 1959  Chemical Thermodynamics. Englewood C l i f f s . N.Y.  Rapid a n a l y t i c a l methods. 19: 76-78.  Prentice-Hall Inc.  Plant physiology  and Stephenson, H. F. Nature of the reactions of monocalcium phosphate monohydrate i n s o i l s : 1. The solutions that react with the s o i l . S o i l S c i . Soc. Amer. Proc. 23: 12-22.  33.  Louw, H. A., and Webley, D. M., 1959 A study of s o i l bacteria dissolving bacteria dissolving certain mineral phosphate f e r t i l i z e r s and related compounds. Journal of applied bacteriology. 22: 227233.  34.  Lyon, T. L., Buckman, H. 0., and Brady, N. 1952 Nature and Properties of S o i l s .  Macmillan N.Y.  35.  Mack, A., and Barber, S. A. 1960 Influence of temperature and moisture on s o i l phosphorus. 1. E f f e c t on s o i l phosphorus f r a c t i o n s . S o i l S c i . Soc. Amer. Proc. 24: 381-385.  36.  Moreno, E.C., Brown, E. W., and Osborn, G., 1960 S t a b i l i t y of dicalcium phosphate dihydrate i n agueous solutions and s o l u b i l i t y of octocalcium phosphate. S o i l S c i . Soc. Amer. Proc. 24: 99-102.  37.  Nelson, L. B. In A.G. Newman ed. Advances i n Agronomy. 1956 Press Inc. 332-333.  Academic  98 38.  Nielsen, K. F., Halstead, R. L., McLean, A. J . , Holmes, R.M. 1960 and Bourget, J . J . The influence of s o i l temperature on the growth and mineral composition of oats. J . of S o i l S c i . 40: 225-263.  39.  Norland, M. A., Starostka, R. W., and H i l l , W. L. 1958 Crop response to phosphate f e r t i l i z e r s as influenced by l e v e l of phosphorus s o l u b i l i t y and time of placement p r i o r to planting. S o i l S c i . Soc. Amer. Proc. 22: 529-533.  40.  Olsen, S. R., Cole, C. V., Watanabe, F., and Dean, L. A. 1954 Estimation of available phosphorus i n s o i l by extraction with sodium bicarbonate. U.S.B.A. Grc. 939. Washington, D.C.  41.  Owens, L., Lawton, L. S., Robertson, L. S., and Apostolakis, N. 1955 Laboratory, greenhouse and f i e l d studies with mixed f e r t i l i z e r s varying i n water- soluble phosphorus content and p a r t i c l e s i z e . SaLl S c i . Soc. Amer. Proc. 19: 315-319.  42.  Parups, E. V., and Nielsen, K. F., 1960 The growth of tobacco at certain temperatures and nutrient levels i n greenhouse. Can. J . of Plant S c i . 40: 281-287  43. 1960  44  45.  Nielsen K, F., and Bourget S. J . , The growth, nicotene and phosphorus content of tobacco grown at d i f f e r e n t s o i l temperatures, moisture and phosphorus l e v e l s . Can. J . of PI. S c i . 40: 516-523.  Patton, J . and Reeder, W., 1956 New indicator for t i t r a t i o n f o r t i t r a t i o n of calcium with (Ethylaae d i n i t r i l o Tetraacetate) Anal. Chem. 28: 1026-1028. P i e r r e , W. H., and Norman, A. G. 1953 S o i l and f e r t i l i z e r phosphorus. Vol. 4 Academic Press.  Agronomy  46.  Rennie, D. A., and Soper R. J . , 1958 The e f f e c t of nitrogen additions on f e r t i l i z e r phosphorus a v a i l a b i l i t y , i i . J . S o i l S c i 9: 155-167.  47.  Richards, L. A., 1949  48. 1944  Methods of measuring s o i l moisture tension S o i l S c i . 68: 95-112. and Weaver, L. R., Moisture retention by some i r r i g a t e d s o i l s as related to s o i l moisture tension. J . A g r i . Research 69: 215-235.  99 49.  Richards, S. J . , Hagan R. N., and McCalla, T.M. 1952 S o i l Temperature and plant growth. Agronomy 2; S o i l physical conditions and plant growth. 303-480. Ac. Press. Inc. New York.  50.  Robinson, R. R., Sprague, V. G., and Gross, C. F. 1959 The r e l a t i o n of temperature and phosphate placement to growth of clover. S o i l S c i ] Soc. Amer. Proc. V o l . 23: 225-228.  51. 1942  Phosphorus f i x a t i o n as affected by soil"temperature. J . Am. Soc. Agron. 34:301-306  52.  Seatz, L i F., Sturges, A. J . , and Kramer, J.C. 1959 The influence of organic matter additions on rock phosphate a v a i l a b i l i t y to crops. "Soil S c i . Soc. Amer. Proc. 23: 374-376  53.  Simpson,"K. 1960  54. 1960 55.  E f f e c t of supplementing r a i n f a l l on the uptake of phosphorus from superphosphate by potatoes. J . of S c i . Food and A g r i . 2: 71-79. E f f e c t of s o i l temperature and moisture on the uptake of phosphorus by oats. J . of S c i . Food and Agr. 8: 449-456, I.'":-.  Stanford, G., and Hignet, T.P., 1957 F e r t i l i z e r s development i n T.V.A's. Process and Agronomic Implications.  New  56.  S t e e l , R. D. G., and T o r r i e , J . , 1960 P r i n c i p l e s and Procedures of S t a t i s t i c s McGraw H i l l .  57.  Taylor, S. A., 1960  58.  Terman, G. L., Bouldin, D. R., and Lehr, J . R., 1958 Calcium phosphate f e r t i l i z e r s : 1 A v a i l a b i l i t y to plants and s o l u b i l i t y i n s o i l s varying i n pH S o i l S c i . Soc. Amer. Proc 22: 25-32  59. 1960  They're boosting a l f a l f a seed y i e l d s i n the West. Crops and S o i l s . 13: 875  Derment, J . D., and Clements L. B., Crop response to ammohiated superphosphate and dicalcium phosphate as affected by granule size, water s o l u b i l i t y , and time of reaction with s o i l . Agr. and Food Chem. 8:13.  100 60.  Thomas, H. D., 1960  61.  Thompson, L. M., and Black, C. A., The effect temperature i n the mineralization of 1948 s o i l organic phosphorus. S o i l S c i . Soc. Amer. Proc. 12: 323-326.  62.  Thurlow, D., and Smith, F. W., 1960 Rock phosphate and superphosphate as sources of phosphorus and calcium for a l f a l f a . Agro. Journal 52: 251-254.  63.  Webb, J . R., and Pesek, J . T., 1959 An evaluation of phosphorus f e r t i l i z e r s varying in water s o l u b i l i t y : i i Broadcast application for corn. S o i l S c i . Soc. of Amer. Proc. 23: 381-384.  64.  Wild, A., 1949  ,--  The effect of s o i l reaction on the a v a i l a b i l i t y of native and applied phosphorus. Dissertation abstracts. 20: 2470-2477.  The retention of phosphate by s o i l . J . of S o i l S c i . 1: l u  t  A review  

Cite

Citation Scheme:

        

Citations by CSL (citeproc-js)

Usage Statistics

Share

Embed

Customize your widget with the following options, then copy and paste the code below into the HTML of your page to embed this item in your website.
                        
                            <div id="ubcOpenCollectionsWidgetDisplay">
                            <script id="ubcOpenCollectionsWidget"
                            src="{[{embed.src}]}"
                            data-item="{[{embed.item}]}"
                            data-collection="{[{embed.collection}]}"
                            data-metadata="{[{embed.showMetadata}]}"
                            data-width="{[{embed.width}]}"
                            async >
                            </script>
                            </div>
                        
                    
IIIF logo Our image viewer uses the IIIF 2.0 standard. To load this item in other compatible viewers, use this url:
http://iiif.library.ubc.ca/presentation/dsp.831.1-0105853/manifest

Comment

Related Items