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Effects of fertilization on the nutrient and organic matter dynamics of reclaimed coal-mined areas and… Ziemkiewicz, Paul F. 1979

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I  EFFECTS OF FERTILIZATION ON THE NUTRIENT AND ORGANIC MATTER DYNAMICS OF RECLAIMED COAL-MINED AREAS AND NATIVE GRASSLANDS IN SOUTHEASTERN BRITISH COLUMBIA by Paul F. Ziemkiewicz B.S. Utah State U n i v e r s i t y , 1973 M.S. Utah State U n i v e r s i t y , 1975 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF • THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY  in THE FACULTY OF GRADUATE STUDIES (Faculty of F o r e s t r y , U n i v e r s i t y of B r i t i s h Columbia  We accept t h i s t h e s i s as conforming to the required standard  THE UNIVERSITY OF BRITISH COLUMBIA October, 1979  (c)  Paul F. Ziemkiewicz, 1979  In presenting t h i s thesis in p a r t i a l f u l f i l m e n t of the requirements f o r an advanced degree at the U n i v e r s i t y of B r i t i s h Columbia, I agree that the Library s h a l l make i t f r e e l y a v a i l a b l e for reference and study. I further.agree that permission for extensive copying of t h i s thesis f o r s c h o l a r l y purposes may be granted by the Head of my Department or by his representatives.  It i s understood that copying or p u b l i c a t i o n  of t h i s thesis f o r f i n a n c i a l gain s h a l l not be allowed without my written permission.  Department of The U n i v e r s i t y of B r i t i s h Columbia 2075 wesbrook Place Vancouver, Canada V6T 1W5  Ay  t  ABSTRACT Reclamation of coal mining disturbances has been undertaken on a large scale i n B r i t i s h Columbia since 1972.  Mining occurs p r i m a r i l y in a narrow b e l t  in southeastern B.C. from the international boundary northward p a r a l l e l to the continental divide to the headwaters of the Elk River at elevations of 1,000 m to 2*300 m. Since reclamation began, most treated areas have been f e r t i l i z e d annually as a precaution against reclamation f a i l u r e .  While t h i s practice has often  maintained productive and a t t r a c t i v e reclamation s i t e s i t was not known whether the maintenance f e r t i l i z a t i o n was necessary and what e f f e c t i t was having on plant community development. To answer these questions two productive reclaimed areas and two a d j a cent native, undisturbed grasslands were selected.  One set of plots was amid  montane vegetation and the other amid subalpine vegetation.  On each of the  four s i t e s , paired plots were established and shoot, d e t r i t u s and root biomass l e v e l s were measured over a 14-month period.  One of the paired plots was f e r t -  i l i z e d in the spring. N, P and K analyses were done on s o i l and plant samples so that organic matter and nutrient f l u x in the four plant community compartments could be expressed as mass per unit ground surface. Two phases in reclaimed area development, were i d e n t i f i e d .  The develop-  ment phase was characterized by d e t r i t u s accumulation and minor root mass t u r n over in the f a l l .  F e r t i l i z a t i o n had a profound influence on t h i s phase mainly  in stimulating shoot production though root production Was stimulated to a l e s s e r degree.  The withdrawal of maintenance f e r t i l i z a t i o n resulted in a severe drop  in production and nutrient accumulation with a large part of y e a r l y N and P uptake immobilized in surface d e t r i t u s by f a l l . presented t h i s phase.  The subalpine reclaimed area r e -  The data indicate that maintenance f e r t i l i z a t i o n w i l l be  i i necessary to prevent degeneration of the plant community. The montane reclaimed area represented the mature phase of development. This phase may not indicate attainment of a steady s t a t e , but i t appeared to be capable of storing and c y c l i n g s u f f i c i e n t nutrients that withdrawal of maintenance f e r t i l i z a t i o n resulted in no apparent adverse e f f e c t s .  Rather, due to the mid-  summer drought, f e r t i l i z a t i o n of t h i s reclaimed area i n h i b i t e d root production while i t stimulated shoot production.  The additional shoot production could  not be maintained through the dry period, so that shoot standing crop through the summer was not influenced by f e r t i l i z a t i o n . The native areas were characterized by massive root systems which caused the bulk of nutrient exchanges to occur within plant and from root to s o i l to root.  Thus the surface d e t r i t u s system played a minor r o l e in n u t r i e n t c y c l i n g  r e l a t i v e to the reclaimed areas.  F e r t i l i z a t i o n of natives areas stimulated shoot  production and d e t r i t a l decomposition so root:shoot r a t i o s narrowed and d e t r i t u s l e v e l s dropped a f t e r f e r t i l i z a t i o n . The reclaimed areas were less stable than the native areas in r e l a t i o n to water and nutrient stress.  However, the montane reclaimed area seemed s e l f -  s u f f i c i e n t in. nutrients and should continue to develop without annual f e r t i l i z a tion.  The subalpine reclaimed area i s not nutrient s e l f - s u f f i c i e n t and w i l l r e -  quire continued treatment.  Dr. J . V. Thirgood Major Professor  Dr. R. M. Strang Thesis Supervisor  iii TABLE OF CONTENTS Page ABSTRACT  i  TABLE OF CONTENTS  iii  LIST OF FIGURES  vii  LIST OF TABLES  . viii  ACKNOWLEDGEMENTS  ix  1.0  INTRODUCTION  1  1.1  THE SETTING  1  1.2  THE PROBLEM  2  1.3  STATE OF THE ART  6  1.4  THE APPROACH  6  2.0  3.0  THEORY 2.1  ENERGETICS  7  2.2  NUTRIENT CYCLING  8  LITERATURE REVIEW 3.1  3.2  4.0  7  n  ENERGETICS AND NUTRIENT CYCLING  11  3.1.1  A r c t i c Tundra  11  3.1.2  Alpine Tundra  14  3.1.3  Temperate Grasslands  18  ROLE AND DYNAMICS OF NUTRIENTS IN PLANT COMMUNITIES  20  3.2.1  Nitrogen  20  3.2.2  Phosphorus  22  3.2.3  Potassium  22  METHODS AND MATERIALS  23  4.1  THE STUDY AREA . . . .  23  4.2  EXPERIMENTAL DESIGN  26  4.3  THE STUDY SITES  29  iv  5.0  4.3.1  Reclaimed Areas  Page 29 ~  4.3.2  Native Grasslands  .32  4.4  Sampling  33  RESULTS 5.1  34  TEMPORAL DISTRIBUTION OF ORGANIC MATTER  34  5.1.1  Montane Native Grassland  34  5.1.2  Montane Reclaimed Area  36  5.1.3  Subalpine Native Grassland  40  Subalpine Reclaimed Area  42  . 5.1.4 5.2  NET CHANGES IN ORGANIC MATTER  5.3  NUTRIENT CONCENTRATIONS  50  5.3.1 Nitrogen  50  5.3.2 Phosphorus  52  5.3.3 Potassium  53  TEMPORAL DISTRIBUTION OF NITROGEN  55  5.4.1  Montane Native Grassland  55  5.4.2  Montane Reclaimed Area  61  5.4.3  Subalpine Native Grassland  63  5.4.4  Subalpine Reclaimed Area  64  5.4  5.5 TEMPORAL DISTRIBUTION OF PHOSPHORUS  •.  45  66  5.5.1  Montane Native Grassland  66  5.5.2  Montane Reclaimed Area  69  5.5.3  Subalpine Native Grassland  71  5.5.4  Subalpine Reclaimed Area  71  5.6 TEMPORAL DISTRIBUTION OF POTASSIUM  72  5.6.1  Montane Native Grassland  72  5.6.2  Montane Reclaimed Area  74  5.6.3 5.6.4  Subalpine Native Grassland Subalpine Reclaimed Area  77 78  V Page 5.7  5.8  5.9  6.0  NITROGEN DYNAMICS  79  5.7.1  Montane Areas  80  5.7.2  Subalpine Areas  82  PHOSPHORUS DYNAMICS  82  5.8.1  Montane Areas  82  5.8.2  Subalpine Areas  86  POTASSIUM DYNAMICS  88  5.9.1  Montane Areas  88  5.9.2  Subalpine Areas  91  DISCUSSION  91  6.1  EFFECTS OF FERTILIZATION  6.2  FATE OF APPLIED NUTRIENTS  97  6.2.1  Nitrogen  98  6.2.2  Phosphorus  101  6.2.3  Potassium  104  6.3  "  SUMMARY OF DISCUSSION  91  106  7.0  IMPLICATIONS FOR RECLAMATION  109  8.0  CONCLUSIONS  112  9.0  AREAS FOR FURTHER RESEARCH  115  10.0  LITERATURE CITED  116  11.0  BIBLIOGRAPHY  121  APPENDIX I  N, P, K, Ca, Mg d i s t r i b u t i o n  128  APPENDIX II  net changes in Ca and Mg masses  139  APPENDIX III  p r e c i p i t a t i o n during study  144  APPENDIX IV  p r e c i p i t a t i o n during study  147  APPENDIX V  mean monthly temperatures  150  APPENDIX VI  monthly snowfall in study area (1973-1977)  153  Page -?  day  -1  APPENDIX VII  net change in organic matter (g m  )  APPENDIX VIII  nutrient concentrations in shoots, roots and d e t r i t u s . . .  156 159  vi i LIST OF FIGURES Page  Figure 1.  Map of Canada showing location of the study area  2  Figure 2.  Model depicting energy flow through an ecosystem ( a f t e r B a t z l i , 1974)  9  Figure 3.  S i m p l i f i e d model representing energy and nutrient flows through an ecosystem  10  Figure 4.  Schematic diagram of p l o t layout  27  Figure 5.  Shoot and d e t r i t u s masses on the montane native area Root masses on the montane native and reclaimed areas  35 37  Figure 7.  Shoot and d e t r i t u s masses on the montane reclaimed area  39  Figure 8.  Shoot and d e t r i t u s masses on the subalpine native area  41  Figure 9.  Root masses on the subalpine native and reclaimed area  43  Figure 10.  Shoot and d e t r i t u s masses on the  Figure 6.  subalpine reclaimed area  44  Figure 11.  Shoot and d e t r i t u s N masses  56  Figure 12.  Root N masses  57  Figure 13.  Total s o i l N masses  59  Figure 14.  S o i l NO3  masses  60  Figure 15.  Shoot and d e t r i t u s P masses  67  Figure 16.  Root P masses  68  Figure 17.  S o i l a v a i l a b l e P masses  70  Figure 18.  Shoot and d e t r i t u s K masses  73  Figure 19.  Root K masses  75  Figure 20.  S o i l a v a i l a b l e K masses  76  vi i i LIST OF TABLES Page  Table 1.  A e r i a l standing crop by species on nine Kaiser Resources reclaimed areas  31  Table 2.  F e r t i l i z a t i o n history of Lower C seam  30  Table 3. Table 4.  F e r t i l i z a t i o n history of the Assembly Pad Net change in shoot, d e t r i t u s and root masses on the montane areas  32 46  Table 5.  Net change in shoot, d e t r i t u s and root masses on the subalpine areas  47  Table 6.  N dynamics within shoot, d e t r i t u s , root'and s o i l compartments of the montane areas  Table 7.  Table 8.  Table 9.  Table 10.  .....  81  N dynamics within shoot, d e t r i t u s , root and s o i l compartments of the subalpine areas  83  P dynamics w i t h i n shoot, d e t r i t u s , root and s o i l compartments of the montane areas  85  P dynamics within shoot, d e t r i t u s , root and s o i l compartments of the subalpine areas  87  K dynamics within shoot, d e t r i t u s , root |and s o i l compartments of the montane areas  89  i  Table 11.  K dynamics within shoot, d e t r i t u s , root and s o i l compartments of the subalpine areas  92  Table 12.  Estimated f e r t i l i z e r N uptake, e f f e c t and e f f i c i e n c y  99  Table 13.  Estimated f e r t i l i z e r P uptake, e f f e c t and e f f i c i e n c y  102  Table 14.  Estimated f e r t i l i z e r K uptake, e f f e c t and e f f i c i e n c y  105  ACKNOWLEDGEMENTS Many i n d i v i d u a l s and organizations co-operated to make t h i s study a succes.  Deserving the utmost c r e d i t i s Mr. A. W. M i l l i g a n , D i r e c t o r , Reclamation  Department, Kaiser Resources Ltd.  Without his help in arranging approvals,  labor and f a c i l i t i e s t h i s study would not have been possible.  Also, deserving  of special thanks i s Dr. L. M. Lavkulich of the S o i l s Department, UBC for most generously providing the chemical analyses necessary for t h i s study.  Without  the support of these two i n d i v i d u a l s and the organizations which they represent this project would have remained a pipe dream. Many thanks are also due by Advisor, Dr. J . V. Thirgood and the other members of my committee:  Dr. A. A. Bomke, Dr. V. C. Brink, Dr. J . P. Kimmins  and Dr. R. M. Strang.  These i n d i v i d u a l s provided e x c e l l e n t advise and support  throughout the study.  I am p a r t i c u l a r l y indebted to Dr. Strang for assuming the  r e s p o n s i b i l i t i e s of Advisor during Thesis preparation. These acknowledgements would be incomplete without mention of the cont r i b u t i o n s made by members of my f i e l d crews.  These i n d i v i d u a l s dug holes, sur-  veyed p l o t s , pounded stakes, washed roots and clipped endlessly while the weather was i n v a r i a b l y too c o l d , too hot or too pleasant. the longest deserve special mention: and Norman Johnson.  Those who presevered with me  Jennifer Hansen, Barbara Hunt, Ken MacDonald  Mr. Johnson's dedication and s k i l l in c o l l e c t i n g Sample #6  portends a bright future in Biology. F i n a l l y by deepest thanks to my w i f e , C h r i s t i n e , for her support and understanding, and for typing the d r a f t copy of the Thesis.  1.0  INTRODUCTION  1.1  THE SETTING Coal mining in B r i t i s h Columbia has grown in recent years and has become  a major component of the p r o v i n c i a l economy.  Production has increased from ab-  out 1,000,000 t in 1969 to 11,000,000 t in 1973.  This level has since been main-  tained while value of the t o t a l product has increased from $6,800,000 in 1969 to $154,600,000 in 1975 (Warden, 1975). Most of the mining occurs in the Elk River Valley of southeastern B r i t i s h Columbia (Figure 1). hods.  Over 80% of B.C.'s coal i s extracted by surface mining met-  Two companies currently account for most of the production:  Resources Ltd. in Sparwood and Fording Coal Ltd. in E l k f o r d .  Kaiser  Most of the coal  i s shipped under long-term contract to Japan for conversion to coke, the reduction agent in the production of i r o n . With 364,000 ha of the province under coal lease the potential for land use c o n f l i c t s and environmental damage i s great.  The Elk Valley coal mines have  been under p a r t i c u l a r scrutiny by p r o v i n c i a l agencies due to the large scale of the disturbances and the big game, f i s h e r i e s and aesthetic values thus threatened. The Elk Valley i s in the extreme southeastern corner of B r i t i s h Columbia. Elevations of coal outcrops range from 1,000 to 2,200 m elevation and annual prec i p i t a t i o n ranges from 600 to 1,400 mm.  P r e c i p i t a t i o n increases with e l e v a t i o n .  Vegetation ranges from a lodgepole pine (Pinus contorta Dougl.)-Douglas f i r (Pseudotsuga menziesii (Mirbel) Franco) forest in the v a l l e y bottom with i n t e r spersed grasslands and aspen (Populus tremuloides Michx.) forests to a subalpine f i r (Abies lasiocarpa (Hook.) Nutt.)-Engelmann spruce (Picea engelmannii  Parry)  dominated forest at higher elevations with grasslands occuring on west-facing slopes.  ( A l l taxonomy follows Hitchcock and Cronquist, 1973.) While the p r o v i n c i a l government has required reclamation of these d i s -  turbed areas, the mining companies have been responsible f o r developing appropr i a t e reclamation techniques.  These have evolved into methods t h a t , at l e a s t  2  Figure 1.  Map of Canada showing location of the study area.  in the short term, often give good r e s u l t s . A f t e r mining, s p o i l s are recontoured to a maximum slope of 28°. tempt i s made to  store or reapply t o p s o i l .  No a t -  Selected grass and legume seed (about  50 kg ha"*) are broadcast and about 200 kg ha"* of 13-16-10 f e r t i l i z e r applied and harrowed.  The same amount of f e r t i l i z e r i s reapplied annually as an expensive  precaution against reclamation f a i l u r e .  This cautious approach is j u s t i f i e d in  l i g h t of the lack of l i t e r a t u r e concerning the rate at which overburden becomes capable of supplying the nutrient requirements of a plant community. 1.2  THE PROBLEM In reclamation l e g i s l a t i o n pertinent to North American wildlands, the  term " s e l f - s u s t a i n i n g , productive plant cover" often defines land which has  3 been successfully reclaimed.  The s e l f - s u s t a i n i n g state i s the goal of most r e -  clamation programs on non-cultivated land and represents the point at which the operator can recover the reclamation bond and return the land to the owner.  If  the land proves incapable of sustaining adequate plant cover the owner i s r e sponsible for m i t i g a t i o n of resultant environmental impacts. In the milder climates of the eastern United States and Europe reclamation has been practiced long enough that a large body of information has developed regarding the long-term behavior of reclaimed areas. Medvick, 1973).  (Bauer, 1973;  In western Canada we do not have the luxury of time and already  one copper mining company in B.C. has c o l l e c t e d i t s reclamation bond while several western coal mines seem on the verge of terminating operations.  So i t i s c r i -  t i c a l that the p r o v i n c i a l governments acquire techniques which w i l l allow at l e a s t an educated guess as to whether or not an area i s indeed reclaimed.  Other-  wise the reclamation bond may be paid back to the operator on land that s t i l l requires c o s t l y reclamation work. techniques.  The operators also might benefit from such  For presently, maintenance f e r t i l i z a t i o n i s extremely c o s t l y and in  many cases probably unnecessary or even harmful.  If nutrient s e l f - s u f f i c i e n t  areas could be i d e n t i f i e d a great savings in time, labor and precious f e r t i l i z e r would be r e a l i z e d . This study was conducted in the mountainous region of southeastern B r i t i s h Columbia.  Study s i t e elevations range from 1,500 to 2,100 m e l e v a t i o n .  The region i s subject to periodic summer droughts.  The short, often cool and  dry growing seasons impose constraints on the reclamation plant communities, and l i t t l e i s known about the f i t n e s s of the agronomic grasses and legumes to these harsh conditions.  Some authors (Bell and Meidinger, 1977) have suggested that  these agronomic species cannot survive in the Rocky Mountains without i r r i g a t i o n and continued f e r t i l i z a t i o n .  Numerous species can survive without i r r i g a t i o n  but several factors m i l i t a t e against the development of nutrient s e l f - s u f f i c i e n c y in t h i s region.  1)  Topsoil (LFH, Ah horizons) i s scarce and, in B r i t i s h Columbia,  4  i t i s not replaced a f t e r coal mining.  This forces reclamation to commence on  nutrient-poor overburden and coal s p o i l .  Therefore, a large part of the r e -  clamation e f f o r t must be directed to accelerating the development of a s o i l " i n s i t u " and "reclamation" has become synonymous with accelerated succession.  2)  The agronomic species used in reclamation have been, to varying degrees, bred and selected to meet the requirements of forage crops.  These include maximization  of shoot growth and maintenance of high nutrient q u a l i t y in the shoots. S o i l development in grass-forb communities i s dominated by the rate of fibrous root production and turnover.  Root production, turnover and q u a l i t y are  of c r i t i c a l importance in the reclaimed areas.  Shoot production and, p a r t i c u l a r l y ,  surface d e t r i t u s production are also c r i t i c a l .  For, i f i n e f f e c t i v e translocation  to the roots occurs p r i o r to shoot death then carbohydrates and nutrients enter the d e t r i t u s pool.  I n e f f e c t i v e translocation can r e s u l t from f r o s t or drought  k i l l i n g of shoots p r i o r to senescence. Once carbohydrates and nutrients enter the d e t r i t u s system t h e i r fate i s l a r g e l y determined by decomposers.  I f decomposition operates at a high rate a  great deal of d e t r i t a l C w i l l leave the system as CO2 while the remainder w i l l become stable humic and f u l v i c acids.  The i n f i l t r a t i o n of these organic acids  into the s o i l p r o f i l e i s a function of physical disturbance, climate, s o i l texture and s o i l pH.  In the dry, heavy and basic mine s p o i l s of the study area the  m o b i l i t y of these organic acids i s l i m i t e d .  Nutrients released in d e t r i t a l de-  composition then become a v a i l a b l e to plants j u s t below the s o i l surface.  The  penetration of NO3 and NH4 i s l a r g e l y determined by the rate of plant uptake and in the case of NH^ by s o i l CEC as w e l l . beyond the s o i l surface.  In a l k a l i n e s o i l s P i s v i r t u a l l y immobile  Therefore, even with rapid d e t r i t a l decomposition, in  a system where n u t r i e n t return i s largely in the form of surface d e t r u i t u s , o r ganic acids and nutrients tend to remain near the surface.  This r e s u l t s in de-  velopment of a shallow and small root system with a l i m i t e d capacity to store carbohydrates and nutrients over winter or withstand summer drought.  S o i l de-  5  velopment would also be retarded as the organic compounds c r i t i c a l to development of the Ah horizon would be concentrated at the s o i l surface. I f decomposition operates at a low rate as i s often the case in cold or dry climates then s o i l development i s further retarded.  In low decomposition  environments d e t r i t u s tends to accumulate and acts as a nutrient and carbohydrate "sink".  Thus, in cold or dry environments the importance of i n - p l a n t c y c l i n g i s  heightened.  I t i s , therefore, not surprising that tundra and grassland systems  are characterized by large root:shoot r a t i o s and that f i r e is a c r i t i c a l f a c t o r in o x i d i z i n g accumulated d e t r i t u s and maintaining steady s t a t e . Many reclamation studies in the A r c t i c , Alpine and Subalpine have r e ported good i n i t i a l growth but poor persistence. 1974; Younkin, 1976).  (Brown et al_., 1976; H u l l ,  The decline in vigor i s often matched by an accumulation  of dead plant material on the s o i l surface (Younkin, i b i d . )  Usually, t h i s decline  in vigor i s coincident with the withdrawal of f e r t i l i z a t i o n .  While other factors  undoubtedly contribute to this d e t e r i o r a t i o n , mineral n u t r i t i o n i s c r i t i c a l due to the depression of decomposition and nutrient c y c l i n g in cold regions (Hagg, 1972).  Consequently, repeated f e r t i l i z a t i o n i s often required in these areas  (Brown et al_.,. 1978). So, several c r i t i c a l factors emerged in assessing the nutrient s t a b i l i t y of the reclaimed area plant communities. cycling?  What was the extent of i n - p l a n t nutrient  Which e x t r a - b i o t i c exchange processes were dominant, root to shoot to  d e t r i t u s or root to s o i l to root? more rapid s o i l development.  Dominance of the l a t t e r process would indicate  Native, undisturbed plots were valuable in demon-  s t r a t i n g the type of processes which tend to maintain a productive steady state grassland in the region. on these processes.  Of p a r t i c u l a r importance was the e f f e c t of f e r t i l i z a t i o n  Also, the e f f e c t s of f e r t i l i z a t i o n on the rate of d e t r i t a l  decomposition, magnitude of the overwintering root mass and i t s annual turnover were c r i t i c a l in e s t a b l i s h i n g the nutrient s t a b i l i t y of the reclaimed areas.  6 1.3  STATE OF THE ART Most of the long-term n u t r i e n t c y c l i n g work has come from forest ecology  studies.  In these studies the huge biomasses required sophisticated sampling  methods and a great deal of manpower (Cole et al_., 1967; Kira and S h i d e i , 1967). Most tundra and grassland studies have extended f o r no more than one growing season so that overwinter root a t t r i t i o n and d e t r i t a l changes could not be measured. nutrients.  Also, most studies were confined e i t h e r to biomass or one or a few The great majority of studies were intended to characterize the d i s -  t r i b u t i o n of biomass in a system or i n d i v i d u a l plant compartments ( i . e . roots, shoots, d e t r i t u s ) .  In some studies nutrient concentrations in plant parts and  d e t r i t u s were examined. These studies have developed the basis by which nutrient c y c l i n g can now be used as an hypothesis testing and p r e d i c t i v e t o o l . already been made i n forest ecology.  Such applications have  The a p p l i c a t i o n to reclamation plant ec-  ology i s explored in t h i s study. 1.4  THE APPROACH  The approach taken in t h i s study involved basing a l l estimates on b i o mass per unit area in the three predominantly organic compartments (root, shoot, detritus).  Nutrient analyses were then made of the bulked samples as well as  s o i l samples so that, within each treatment, biomass, N, P, and K could be dimensioned as g rrf^.  With the addition of a known amount of N, P and K as f e r t i l i z e r  the fates of the added nutrients were estimated as the deviations from the unf e r t i l i z e d paired p l o t .  Also, by using t h i s method and sampling over a 14-month  period the e f f e c t s of f e r t i l i z a t i o n could be assessed as net accumulations to, and losses from, the various compartments. Two reclaimed areas and two native, undisturbed grasslands were included in the study.  The native s i t e s served as c o n t r o l s , i n d i c a t i n g the e f f e c t s of  c l i m a t i c abberations on what were assumed to be stable plant communities. S t a b i l i t y was defined by the amplitude of system f l u c t u a t i o n s (net pro-  7 d u c t i v i t y , standing crop, nutrient l e v e l s ) r e s u l t i n g from perturbations (Odurn, 1971a).  Thus, using the native areas as representative steady state systems  the e f f e c t s of two major perturbations: f e r t i l i z a t i o n and c l i m a t i c extremes (however manifest) could be measured.  The amplitude of f l u c t u a t i o n s in the study  parameters on reclaimed areas could then be compared to those of native areas. The degree to which these perturbations resulted in greater long-term impact on the plant communities was taken as a measure of the system's s t a b i l i t y . 2.0  THEORY A l l plant communities are e s s e n t i a l l y dynamic units through which energy  and nutrients flow.  In f a c t , a plant community at any given time i s t h i s flow  of energy and n u t r i e n t s , " f r o z e n " for an i n s t a n t . are photosynthesis pounds.  The mechanisms of energy f l u x  and r e s p i r a t i o n , the creation and destruction of organic com-  Nutrients other than carbon, hydrogen and oxygen flow through the com-  munity in t h e i r own c y c l e s .  The instantaneous quantities of energy and nutrients  in the system's b i o t i c , d e t r i t a l and a b i o t i c compartments represent the standing crop.  Fluxes between compartments indicate the rate of energy flow and n u t r i e n t  cycling. 2.1  ENERGETICS Capture and a l l o c a t i o n of energy by the ecosystem are major functional  characteristics.  Not only do these processes determine the quantity of biomass  supported by the system, but also to a great extent, i t s organization.  E. P.  Odurn (1971b) defines t h i s r e l a t i o n s h i p between structure and function: Organisms, ecosystems and the e n t i r e biosphere possess the essential thermodynamic c h a r a c t e r i s t i c of being able to create and maintain a high state of internal order or low entropy. Low entropy i s achieved by a continual d i s s i p a t i o n of energy of high u t i l i t y ( l i g h t and food, for example) into energy of low u t i l i t y ( i . e . heat). In the ecosystem, "order" in terms of complex biomass structure is maintained by the total community by r e s p i r a t i o n which c o n t i n u a l l y "pumps out d i s o r d e r " . H. T. Odurn (1967), reviewing the works of Lotka (1925) and Schrodinger (1944), suggested that antithermal maintenance is of top p r i o r i t y in any complex  8  system of the real world.  In the ecosystem the r a t i o of t o t a l community r e -  s p i r a t i o n to the t o t a l biomass (R:B) can be considered as the r a t i o of maintenance cost to structure.  If R and B are expressed in c a l o r i e s and d i v i d e d by  absolute temperature, the R:B r a t i o becomes the r a t i o of entropy ( f r e e energy) increase in maintenance to the entropy of ordered structure.  Therefore, i t seems  to follow that as the biomass increases so does the maintenance cost. E. P. Odum (1971c) proposed that the gross primary production:respiration r a t i o i s an index of ecosystem maturity. approaches one.  As succession proceeds the P:R r a t i o  This rule may not always apply to natural ecosystems, p a r t i c u l a r l y  those subject to frequent disturbance or extremely slow dynamics, ( i . e . tundra or desert).  This argument, however, suggests the need for care in comparing  net production data of systems in d i f f e r e n t stages of succession. The energy f l u x through a system i s a u n i - d i r e c t i o n a l energy flow within which minerals c y c l e .  B a t z l i (1974) has produced models describing these energy  flows through various compartments of the ecosystem (Figure 2). This diagram was reworked into a form in which the major compartments in energy and n u t r i e n t flow could be measured. a t i c energy flow diagram.  Figure 3 represents such a schem-  In t h i s approach four major compartments, representing  l i v e shoot and root as well as d e t r i t u s (standing and f a l l e n dead organic matter) and s o i l serve as integrators of environmental or experimentally imposed conditions.  Sampling of these compartments through the course of a year w i l l y i e l d  net changes in mass.  However, i t i s important to remember that the exchange pro-  cesses indicated by the arrows may occur b i - d i r e c t i o n a l l y and simultanteously. 2.2  NUTRIENT CYCLING The study of an ecosystem's energetics w i l l explain a great deal about  i t s functioning and organization.  However, the d e s c r i p t i v e value of energy flow  i s incomplete without some knowledge of the ecosystem's means of capturing and conserving n u t r i e n t s . E. P. Odum (1971d) indicated that as ecosystems progress toward climax,  9  TNSP  TIM  (shortwave) CO, TGP ARsp  TNP HRsp  NAcO HRsp TExM  TERsp  TEnF CO, (longwave)  Thus:  Where:  TGP=TGPrP+TGSP  T=total G=gross P=production N=net Pr=primary S=secondary E=ecosystem Rsp=respiration  TNP=TNPrP+TNSP TERsp=TARsp+THRsp NAcO=TNP-THRsp+NTrM-TNSP NTrM=TIM-TExM  Figure 2.  A=autotroph H=heterotroph Ac=accumulation O=organic matter Tr=transported M=material I=imported Ex=exported F=flux En=energy  Schematic diagram of energy flow through an ecosystem ( a f t e r B a t z l i , 1974).  10 CO. CO,  shortwave radiation  ongwave radiation  photosynthesis  respiration  senescence  shoot  -H  detritus  3  o •H  •H  4-1  u o c  •H  cd  Ni CO  i  tn ca  )-i  4-i  U—I grazers  ~1  60  c  root  •H u  CO  0J  senescence exudation sloughing leaching  eluviation,leaching  deep leaching  Figure 3. A s i m p l i f i e d model representing energy and nutrient flows through an ecosystem.  erosxon  11 nutrient c y c l i n g becomes more e f f i c i e n t .  Also, greater percentages of the cy-  c l i n g nutrients are contained in organic matter.  The rates of nutrient exchange  from one ecosystem compartment to another are more important in determining the structure of an ecosystem than the amounts present at a given time in various compartments.  Therefore, c y c l i n g rates as well as standing crops of nutrients  should be q u a n t i f i e d . 3.0  LITERATURE REVIEW  3.1  ENERGETICS AND NUTRIENT CYCLING The two native grasslands i n t h i s study were located amidst subalpine  and montane vegetation types.  L i t t l e work has been done on the p r o d u c t i v i t y or  nutrient c y c l i n g of grasslands in these vegetation zones.  Consequently, the l i t -  erature review w i l l concentrate on p r o d u c t i v i t y and nutrient c y c l i n g studies most germane to the study areas:  grasslands, a r c t i c tundra and alpine tundra.  This should i l l u s t r a t e , by synthesis, the s t r u c t u r a l and functional r e l a t i o n ships and a l s o , the special problems that might be expected in reclamation of the coal mining areas of B.C. Unfortunately, no comprehensive nutrient studies are a v a i l a b l e from a l pine areas.  While some biomass d i s t r i b u t i o n data are a v a i l a b l e for alpine and  subalpine meadows, the nature of high-elevation nutrient cycles w i l l have to be inferred from the more extensive a r c t i c tundra and grassland studies. 3.1.1  A r c t i c Tundra Almost a l l of the a e r i a l growth of tundra monocotyledeons i s replaced  annually.  However, major portions of the root system may l i v e from two to ten  years (Bunnell, et al_., 1975).  S t i l l there i s a large production of organic  matter, some of which undergoes rapid turnover. The greatest pool of energy resident to the a r c t i c tundra i s i n the dead organic matter.  Bunnell ( i b i d . ) indicated that at Pt. Barrow, Alaska the top  20 cm of s o i l contained from 22 to 45 kg m"^ of d e t r i t u s .  The greatest accumu-  l a t i o n s of organic matter occurred where primary production was lowest.  Detrital  12 mass per unit area was 50 to 400 times greater than net primary production. Grazing has the e f f e c t of accelerating both energy flow and nutrient cycling.  Relative to primary production, grazing i s probably more intense in  the Barrow tundra than in most other systems. to 700 kJ m" ^ y r  There, herbivory ranged from 1.7  over a f i v e year lemming c y c l e .  Without grazing, most o r -  ganic substances l o s t 60% of t h e i r weight within three years following t h e i r death.  This rate i s highly dependent on moisture and other microclimatic f a c -  tors. The cushion growth habit of some tundra plants may be adaptive to more rapid decomposition.  There i s reason to believe that high a r c t i c cushion plants  recycle products of t h e i r decomposition at a higher rate than other plants do (Svoboda, 1972).  Cushion plants hold much of the organic matter under the cushion  and new roots develop in t h i s mass.  Thus, a nutrient exchange system from roots  to s o i l to roots would seem optimized. The s e v e r i t y of the a r c t i c winter induces a low plant growth form. minimizes energy and nutrient loss through t o p k i l l .  Also, a great deal of the  plant community's carbohydrate supplies are underground.  Near Barrow, Alaska  Dennis and Johnson (1970) estimated the r a t i o of below groundrabove standing crop to be 18:1. meadows on Devon Island.  This  ground  Muc (1972) found the same r a t i o to be 7.3:1 in sedge The data of Aleksandrova (1970 a&b) indicate root:  shoot r a t i o s to be 4.8:1 and 7.2:1 in polar desert and a r c t i c tundra r e s p e c t i v e l y in the USSR. McCown and Tieszen (1971) presented preliminary r e s u l t s of l e a f analysis for low molecular weight carbohydrates and polysaccharides of three herbaceous species at Barrow, Alaska.  Low weight carbohydrates ranged from 12 to 17% and  polysaccharides from 20 to 30%.  Muc ( i b i d . ) and Svoboda ( i b i d . ) on Devon Island  found s u b s t a n t i a l l y less carbohydrate present both in roots and shoots of analyzed plants.  Beach Ridge cushion plants contained only about 7% soluble carbohydrates  at the peak.  These data suggest caution in equating stored unavailable energy  13 ( i . e . c e l l u l o s e , l i g n i n ) with a v a i l a b l e stored energy ( i . e . soluble saccharides, starch). Mooney and B i l l i n g s (1965) found a tendency for carbohydrate content to decrease with increasing e l e v a t i o n .  The data of Muc and Svoboda ( i b i d . ) suggest  that carbohydrate content and a v a i l a b i l i t y also decrease with increasing  lati-  tude. Like f i x e d energy, plant nutrients are stored in the tundra's d e t r i t u s . Nutrient budgets of the Barrow, Alaska tundra to the depth of 10 cm reveal that most of the N and P i s in the s o i l in a form unavailable to plants.  Less than  1% of both N and P present in the system reside in the l i v i n g plants. There must be a c o n t i n u a l , rapid turnover in the exchangeable and soluble nutrient pools within the growing season to maintain plant growth.  To s a t i s f y  the demands of growing plants, soluble plus exchangeable N must "turn over" 11 times per growing season, while exchangeable P must be replaced 200 times per season or an average of three times a day.  S u f f i c i e n t a v a i l a b l e nutrients are  not stored in the s o i l ; therefore, primary production u l t i m a t e l y depends on the rate of n u t r i e n t mobilization through decomposition and internal c y c l i n g . The p o s s i b i l i t y of long-term nutrient loss in the tundra i s great, thus the importance of i n - p l a n t c y c l i n g .  In f a c t , most vascular plants at Barrow,  Alaska show strong i n t e r n a l c y c l i n g of n u t r i e n t s , p a r t i c u l a r l y P.  In d r i e r ,  more e f f e c t i v e l y - a e r a t e d s o i l s at Barrow mycorrhizae further f a c i l i t a t e P maintenance in vascular plants.  Despite v a r i a t i o n in s o i l n u t r i e n t l e v e l s , plant  concentrations of N, Ca and K are s i m i l a r among s i t e s , whereas P concentration was greatest on the most productive s i t e s (Bunnell, et aj_. i b i d . ) . F e r t i l i z e r tests (Haag, 1973) in the low a r c t i c tundra near Tuktoyaktuk, NWT suggest that a v a i l a b l e nitrogen i s l i m i t i n g and that N f e r t i l i z a t i o n vascular plant production and protein content. fect.  increases  P f e r t i l i z a t i o n had no such e f -  The data, however, indicate that 10 weeks a f t e r f e r t i l i z a t i o n about 43  to 75% of the 100 and 200 kg h a  - 1  P additions had e i t h e r been f i x e d in unavailable  14 form or had been leached from the rooting zone. Organic s o i l s , p a r t i c u l a r l y those with low pH, can lose considerable P through leaching.  Also, Fe ions made soluble by the low pH tend to f i x phos-  phates in unavailable form. This potential loss of P and other nutrients from the system imposes strong s e l e c t i v e pressure in favor of nutrient conservation.  I t i s not sur-  p r i s i n g that there are few annual plants in tundra f l o r a s ( B l i s s , 1971).  In  perennial plants, l e a f Ca and Mg l e v e l s tend to remain constant throughout the growing season, r e s u l t i n g in a large addition of these elements to the d e t r i t u s pool upon death, whereas N and P tend to be translocated back to stem and roots before l e a f f a l l 3.1.2  (Reiners and Reiners, 1970).  Alpine Tundra Alpine tundras, l i k e t h e i r a r c t i c counterparts, are characterized by  low annual energy budgets.  Alpine climates are s i m i l a r in some respects to those  of the a r c t i c but d i f f e r in the d i s t r i b u t i o n of r a d i a t i o n , s p e c t r a l l y and temporally.  Alpine areas also receive more snow, rain and wind with more intense  sunlight and a higher proportion of u l t r a v i o l e t r a d i a t i o n . pine environments are severe.  Both a r c t i c and a l -  However, the a r c t i c tundra may be more severe in  winter due to the continuous heat loss and the lack of a deep, i n s u l a t i n g snow cover.  The alpine environment on the other hand may be more severe during the  growing season with i t s high wind, high u l t r a v i o l e t and cosmic r a d i a t i o n and i t s cold summer nights ( B i l l i n g s , 1970). As in the a r c t i c tundra, most of the biomass of the alpine tundra i s present in the root system.  The data of Thilenius (1975) suggest that t h i s trend  i s more pronounced in alpine tundra than in subalpine meadows. The root biomass data reported by Thilenius were higher than those noted by other workers. techniques.  This difference was a t t r i b u t e d to more e f f e c t i v e sampling  B l i s s (1963) reported underground biomass to be 3,634 g m~2 in an  alpine mesic sedge meadow.  Scott (1963) reported 1,400 g m"2 for the underground  15 biomass of an alpine mesic s i t e and 750 g m~2 for a x e r i c s i t e in the Medicine Bow Mountains of Wyoming.  However, the depth to which roots were sampled was  not indicated. The roots of alpine plant communities are concentrated near the s o i l surface.  Rehder (1976) indicated that alpine v e r t i c a l root d i s t r i b u t i o n was  roughly 85% from 0-5 cm, 11% from 5-10 cm and 3% 10-15 cm. Knight and Kyte (1975), working in the Medicine Bow Mountains, reported a higher annual rate of l i t t e r decomposition (44%) than was noted by Bunnell, et aj_., (1975) in a r c t i c tundra (30%).  Knight and Kyte also indicated that 70  to 80% of the annual l i t t e r decomposition occurred during the winter and that s o i l was unfrozen under the snow. Despite the s l i g h t l y higher decomposition rate reported by Knight and Kyte, accumulations of organic matter s i m i l a r to those of the Barrow, Alaska tundra were reported by B l i s s (1956) in the Medicine Bow Mountains.  Kuramoto  and B l i s s (1970), working in the Olympic Mountains, also found considerable accumulations of organic matter in s o i l s of subalpine meadows.  A gradient of i n -  creasing organic matter seemed to coincide with colder and wetter microenvironments.  , S o i l s of the subalpine meadows studied by Kuramoto and B l i s s were mostly  young and poorly developed.  Most important in  retarding development i s f i r e ,  p a r t i c u l a r l y in the d r i e r microsites (Fonda and B l i s s , 1969)'. destruction of organic matter and erosion.  Fire r e s u l t s in  This lowers the a b i l i t y of the A-  horizon to absorb and r e t a i n water and to maintain a steady nutrient budget (Ahlgren and Ahlgren, 1960). tard s o i l development.  The abbreviated growing season also tends to r e -  Brooke (1965) estimated 11,000 to 18,500 years as the  time required to accumulate 1 m of organic matter in low moor subalpine communities in Garibaldi Park, B.C. Unfortunately, there has not been a study for alpine tundra comparable to the A r c t i c Tundra Biome P r o j e c t .  Consequently, there i s i n s u f f i c i e n t i n f o r -  16 mation on integrated community r e s p i r a t i o n , photosynthesis and organic matter accumulation to propose an energy flow model for alpine tundra. The carbohydrate cycles of several alpine species over the course of a year were studied by Mooney and B i l l i n g s (1965).  The growth of these species  was found to be quite r a p i d , in some cases commencing under the snow.  The be-  low-ground portions of the plants contained r e l a t i v e l y Targe proportions of the carbohydrate reserves.  A high percentage of these reserves was u t i l i z e d in  growth immediately following snowmelt.  F i f t y percent of the rhizome carbohydrate  reserves was spent in a one-week period of early growth.  Except for t h i s short  period of rapid depletion in below-ground reserves, high l e v e l s of carbohydrates were maintained in above and below-ground parts throughout most of the growing season.  Usually the carbohydrate reserve reached a nadir j u s t before flowering,  while peak storage occurred at the onset of f a l l dormancy.  The carbohydrate  cycle in these alpine plants i s quite s i m i l a r to that in certain a r c t i c plants and seems to be adaptive for short, cold growing seasons (Knight and T h i l e n i u s , 1975). In s i t u f i e l d measurements of net photosynthesis and s o i l r e s p i r a t i o n were made by B i l l i n g s et aj_. (1961) using an infrared gas analyzer in Wyoming's Medicine Bow Mountains.  Maximum net photosynthesis rates ranged from 4.15 to  13.4 mg COg dm"2 hr~*.  Photosynthesis, by Geum r o s s i i (R.Br.) Ser., over the  course of a cloudy day corresponded to changes in l i g h t and temperature.  Similar  measurements of Polygonum b i s t o r t o i d e s (Pursh) in c l e a r weather showed a midday depression probably due to r i s i n g l e a f temperatures and r e s p i r a t i o n .  Net photo-  synthesis of whole sod blocks were measured along with r e s p i r a t i o n , and dry weight gain was estimated at 2.79 g m~2 day There are apparently no comprehensive nutrient c y c l i n g studies a v a i l a b l e for alpine tundra plant communities.  The preceeding review of energetics, though,  suggests general patterns regarding the nature of alpine nutrient c y c l i n g . example, i t seems that the rate of decomposition of surface and below-ground  For  17 d e t r i t u s i s the c r i t i c a l f a c t o r influencing the rates of both energy and nutrient cycling.  Nutrient c y c l i n g in a r c t i c tundra i s slow because only a b o u t  30% of the y e a r ' s l i t t e r f a l l decomposes in the same year (rates of root t u r n over are not a v a i l a b l e ) r e s u l t i n g in substantial organic matter accumulations and nutrient storages.  By comparison, in subalpine grasslands 30-51% of the  y e a r ' s l i t t e r f a l l may decompose over winter alone (Bleak, 1970).  Energy r e -  l a t i o n s h i p s may then i n f e r a great deal about a system's nutrient c y c l i n g . The a v a i l a b l e data indicate strong s i m i l a r i t i e s between energy data from the a r c t i c and alpine tundras.  For example, the high proportion of the biomass  found underground, the accumulation of organic matter in surface horizons and the low net p r o d u c t i v i t y a l l suggest s i m i l a r responses to low energy budgets. Therefore, nutrient c y c l i n g studies taken from the a r c t i c may serve as approximations of nutrient cycles in alpine tundras. Fire may play a greater r o l e in accelerating nutrient c y c l i n g , however, in c e r t a i n alpine microenvironments than in a r c t i c tundra.  The perched water  table over permafrost r e s u l t i n g in the a r c t i c tundra's marshy character tends to retard not only f i r e , but also decomposition. The d i s t r i b u t i o n of organic matter and N, P and K was studied on four alpine plant communities in the Northern Alps (Rehder, 1976).  Marked differences  were evident in p r o d u c t i v i t y as well as nutrient d i s t r i b u t i o n s among communities. Also, while in most communities s o i l N m i n e r a l i z a t i o n exceeded the rate of net shoot N uptake, in one community net shoot N uptake during the growing season exceeded the rate of s o i l N m i n e r a l i z a t i o n thus implying, at least in some cases, a strong " i n t e r n a l N c y c l e " . Kuramoto and B l i s s (1970), studying subalpine meadows i n the humid Olympic Mountains found high t o t a l N l e v e l s in s o i l s of a l l s i x communities studied.  Total N was highest in the surface horizons and decreased with depth.  In a l l but the heath-shrub community C:N r a t i o s were between 8:1 and 3:1 i s commonly quoted for a g r i c u l t u r a l s o i l s ) .  (12:1  Among communities, t o t a l N in the  18 uppermost s o i l layers increased from x e r i c to mesic plant communities.  This r e -  l a t i o n s h i p , n a t u r a l l y , follows the d i s t r i b u t i o n of surface organic matter c l o s e l y and suggests d i f f e r e n t nutrient c y c l i n g relationships for communities along environmental gradients.  The variety of microenvironments at high elevations  due to r a d i a t i o n and wind exposure necessitates caution in generalizing about t h e i r nutrient-energy c y c l e s . A r c t i c and alpine tundra ecosystems show many common features:  low pro-'  d u c t i v i t y , large proportion of the biomass below ground, extreme s c a r c i t y of annual plants and the tendency to accumulate d e t r i t u s .  As the energy budgets  decrease within these systems, t o t a l production drops, as does b i o t i c storage of energy below ground.  However, f i r e seems to play a greater r o l e in the a l -  pine, e s p e c i a l l y on d r i e r areas.  It tends to retard d e t r i t a l accumulation in  many alpine areas as well as accelerate nutrient c y c l i n g .  Also, the ground i s  often unfrozen under alpine snowpacks while the tundra s o i l freezes in the winter. This may explain the higher decomposition reported for alpine tundra. Decomposition i s highly dependent on temperature, moisture and a v a i l a b i l i t y of oxygen.  Since decomposition i s often the major "bottleneck" in the  nutrient c y c l e , i t i s reasonable to suppose that the rate of nutrient c y c l i n g i s highly dependent on the energy f l u x into the s o i l and the s o i l moisture. 3.1.3  Temperate Grasslands Grasslands are characterized by high rates of energy and nutrient flow.  Relative to other ecosystems the period between photosynthetic f i x a t i o n of c a r bon and i t s release in r e s p i r a t i o n i s very short.  Consequently, decomposition  of the large annual l i t t e r f a l l plays an important r o l e in the a v a i l a b i l i t y of nutrients.  Also, the fibrous root system of grasslands undergoes rapid turnover,  a large portion of the root system decomposing and growing back annually.  The  residual organic compounds l e f t a f t e r decomposition of the w e l l - d i s t r i b u t e d root system impart the diagnostic thick Ah horizon to grassland  soils.  Grassland p r o d u c t i v i t y i s highly dependent on p r e c i p i t a t i o n . Thus, pro-  19 d u c t i v i t y estimates vary dramatically with the most marked impact of drought being manifested in the above ground parts.  Rodin and B a s i l e v i c h (1967a) i n -  -2 -2 dicated root:shoot l e v e l s of 840:140 g m and 2,010:450 g m in a wet year f o r two Central Asian grasslands.  The same plant communities sampled in a drought -2  year showed root:shoot l e v e l s of 920:40 g m  and 2,300:180 g m  -2  respectively.  I n h i b i t i o n of root decomposition in the dry year was suggested as the reason for the r i s e of root mass l e v e l s . Grassland production also varies widely within years as the plants r e cover from winter dormancy and e x p l o i t the growing season conditions.  This  dynamic q u a l i t y of grasslands makes p r o d u c t i v i t y estimates based on one standing crop measurement highly suspect. Shoot masses in a Minnesota grassland varied from 2.4 to 94.0 g m from A p r i l to August while root masses declined over the same period from 590 to 280 g m"  2  (Ovington, et al_., 1963).  Studies conducted on grasslands of the USSR indicated that along a gradient of decreasing p r e c i p i t a t i o n and increasing evapotranspiration (north to south) root:shoot r a t i o s increased. levels along the gradient.  This was consistent with s i m i l a r plant biomass So as more x e r i c conditions induce a smaller shoot  mass they provide conditions favorable to production of larger root masses. Root:shoot r a t i o s increased north to south from 3:1 to 10:1 (Rodin and B a s i l e v i c h , 1976b).  The l a t t e r figure was comparable to that found by Ovington, et a l .  ibid. Along the same a v a i l a b l e moisture gradient the annual l i t t e r f a l l decreased north to south.  input  Conversely, with greater root masses in the d r i e r  communities the influence of root turnover on nutrient c y c l i n g became more s i g n i f i c a n t (Rodin and B a s i l e v i c h , i b i d . ) A common feature of grasslands  i s the accumulation of surface d e t r i t u s .  This can cause immobilization of s i g n i f i c a n t proportions of the system's  less  mobile elements (N, Ca, Mg and Fe) while the more mobile elements (K and P) are  20 less l i k e l y to be t i e d up in the d e t r i t u s layer (Rodin and B a s i l e v i c h , 1967c). Thus, f i r e i s an important factor in accelerating nutrient c y c l i n g in  grasslands.  Energy flows through grassland systems have t r a d i t i o n a l l y been viewed as being dominated by grazing.  However, Coleman, et al_. (1976) indicated that,  even in heavily grazed rangelands, the bulk of photosynthetically f i x e d energy passes d i r e c t l y into the detrital-saprophagic pathway.  Considering the amount  of below-ground biomass and i t s reported rates of annual turnover: 25 to 50% (Dahlman and Kucera, 1965; Sims and Singh, 1971) root decomposition seems to be the dominant organic input to grasslands s o i l s . Lauenroth and Whitman (1977) found root masses in western North Dakota increased from annual minima to maxima within a 20-day period in midsummer. This 25% increase in root mass was l a t e r followed by a period of rapid decrease and l a t e r gradual  increase.  Grassland root biomass tends to concentrate in the upper 20 cm of the soil.  Lauenroth and Whitman, i b i d , found 70% of the root mass between depths of  0 to 15 cm while a further 10 to 13% occurred from 15 to 30 cm.  Other studies  (Lauenroth, et al_., 1975) on the Northern Great Plains indicated 85 to 90% of the root mass was in the upper 20 cm of the s o i l . 3.2 3.2.1  ROLE AND DYNAMICS OF NUTRIENTS IN PLANT COMMUNITIES Nitrogen Nitrogen's role as a constituent of amino acids makes i t c r i t i c a l to  plant growth and metabolism.  I t i s required in r e l a t i v e l y large amounts and, as  enzymes regulate many facets of nutrient uptake and transport, i t s deficiency can cause other nutrient d e f i c i e n c i e s to occur. the greatest attention from agronomists.  Consequently, N has received  Since the N cycle involves several  gaseous forms and one of the u t i l i z a b l e forms, NO^, is a r e a d i l y leached anion, N i s subject to loss from the plant system.  Also, some of the N compounds within  the plant are r e s i s t a n t to decomposition and are often t i e d up in unavailable form in the d e t r i t u s or s o i l .  21 N may be added to a plant community via dust inputs, p r e c i p i t a t i o n , micro-organismal f i x a t i o n or by a r t i f i c a l inputs.  N may also be found in c e r -  tain sedimentary rocks, notably shales and c o a l . The decomposition of organic matter to y i e l d a v a i l a b l e N occurs v i a the following reactions: aminization proteins  R-NH  + 2  ^2  *  +  i e a t  +  Products  o t n e r  ammonification R-NH + HOH  NH + R-OH + heat  2  3  This ammonia may: 1.  enter the n i t r i f i c a t i o n process  2.  be d i r e c t l y absorbed by plants  3.  be used by heterotrophs in further decomposition  4.  be f i x e d in expanding-lattice clays in unavailable form  5.  undergo v o l a t i l i z a t i o n under dry, basic conditions  NHj + HOH + OH"  NH + 2H0H 3  nitrification 2 N H  -  Nitrosomonas  +  2N0 + 0 2  Nitrobacter  2  2 N Q  -  2 N Q  +  2 H Q H  +  4 H +  -  The r e s u l t i n g n i t r a t e i s the form most r e a d i l y u t i l i z e d by grasses and forbs.  Since i t s production i s a highly dynamic, b i o l o g i c a l process several  factors can l i m i t i t s a v a i l a b i l i t y :  lack of energy substrate for the heterotrophs,  sub-optimal thermal conditions, lack of oxygen or excessive buildup of H . +  Also, the n i t r a t e may, under reducing conditions, undergo d e n i t r i f i c a t i o n : oufjn 2HN0  3  ilH _  2 H Q H  2HN0„ 2  +4H ZmrT  H  Q  N  2  2  2  +2H -2H0H  N  2  Ammonia v o l a t i l i z a t i o n is of p a r t i c u l a r s i g n i f i c a n c e in western Canadian reclamation since the overburden s p o i l s are usually basic and often dry and warm imimediately a f t e r surface a p p l i c a t i o n of f e r t i l i z e r s .  Leaching of n i t r a t e is the  22 other major factor in N loss as the low cation exchange capacity of these s p o i l s may r e s u l t in the loss of ammonium, and the lack of a massive root system could allow mineralized n i t r a t e s to drain out of the rooting zone. 3.2.2  Phosphorus P functions in the plant as a constituent of sugar phosphates, nucleo-  tides and nucleic acids.  Phosphate c a r r i e r s , phosphorylation and i t s roles i n  the ADP-ATP system are c r i t i c a l in carbohydrate metabolism, r e s p i r a t i o n and photosynthesis.  In the growing plant P concentrates in the meristematic regions.  It i s also abundant in seeds and f r u i t . P i s highly mobile in the plant and w i l l translocate from older leaves to meristematic tissues during periods of d e f i c i e n c i e s .  P d e f i c i e n t plants have  a reddish hue r e s u l t i n g from the i n h i b i t i o n of protein synthesis and subsequent accumulation of sugars in the leaves and stem.  This high-sugar environment i s  conducive to anthocyanin synthesis, hence the red coloration (Meyer, et a l . , 1973). S o i l P i s quite immobile and consequently, r e s i s t a n t to leaching.  In  a c i d i c s o i l s phosphates tend to form nearly insoluble bonds with Fe and Al ions while bonding with Ca in basic s o i l s .  Phosphates may also form very stable  bonds with the clay l a t t i c e , replacing the hydroxide ion. The plant usually absorbs P in the reduced form HPO4 a s o i l pH of 10 does P 0 ^ 3.2.3  occur in substantial  or H^PO^.  Only at  amounts.  Potassium Unlike most nutrients K is not known to form any c r i t i c a l compounds within  the plant. K ion.  I t e x i s t s mainly as low-molecular weight s a l t s or as the unattached  These ions are apparently c r i t i c a l in the opening and c l o s i n g of stomata.  Their supposed role i s in the free energy depression of guard c e l l  cytoplasm  allowing guard c e l l s to achieve turgor in the presence of sunlight (Boyer, 1976). K i s also thought to serve a c a t a l y t i c role in the synthesis of proteins from amino acids.  Apparently, photosynthesis  i s i n h i b i t e d and r e s p i r a t i o n i s increased  23 i n K-deficient plants.  However, the exact mechanism i s unknown.  K i s highly mobile in the plant.  It concentrates in the actively-growing  portion of the plant at the expense of older t i s s u e s . Like P, Ca and Mg, K i s ultimately supplied by decomposing s o i l minerals. Also, l i k e P, plant K i s r e a d i l y translocated so considerable internal c y c l i n g between shoot and root probably occurs. in apparent e q u i l i b r i u m :  S o i l K tends to occur in three forms  unavailable, s l o w l y - a v a i l a b l e and r e a d i l y - a v a i l a b l e .  Unavailable K is that which i s s t i l l bound in the c r y s t a l l a t t i c e of such minerals as b i o t i t e , muscovite and potash feldspars. in the i n n e r - l a m e l l a r spaces of 2:1 c l a y s .  Slowly-available K i s found  Through the wetting and drying pro-  cess t h i s K may become a v a i l a b l e to the plant.  Readily-available K occurs  e i t h e r in solution or on the cation exchange complex.  Because t h i s is a chemical  equilibrium system removal of r e a d i l y - a v a i l a b l e K tends to cause i t s replacement from the other two forms.  Conversely, large additions of f e r t i l i z e r K  tend to drive the equilibrium to the l e f t (Tisdale and Nelson, 1975a). Since ionized K i s a monovalent cation i t w i l l leach out of the s o i l i n s u f f i c i e n t cation exchange capacity e x i s t s .  if  Also, the divalent cations of Ca  and Mg are more strongly.held on the cation exchange s i t e s than K . +  So excessive  l e v e l s of divalent cations can replace potassium on exchange s i t e s or prevent i t s adsorption, inducing 4.0  METHODS AND MATERIALS  4.1  THE STUDY AREA  K deficiency.  The study was conducted on the property of Kaiser Resources Ltd. near Sparwood, B.C., i n the extreme southeast corner of the province. owns the mineral rights in two major coal f i e l d s in the area. Coal F i e l d measures 48 km long by up to 19 km wide.  The company  The Crows Nest  I t contains roughly 12  p o t e n t i a l l y e x p l o i t a b l e seams outcropping within a 760 m s t r a t i g r a p h i c sequence. The Elk River Coal F i e l d l i e s somewhat to the north and east of the Crows Nest F i e l d and contains 7 mineable seams within a 450 m sequence of coal-bearing  24 measures.  The seams vary in thickness from 1.5 to 15.2 m and outcrop between  1,000 and 2,100 m e l e v a t i o n . The overburden rock in these areas consists of sandstone, shales and some conglomerate. 8.4  Upon weathering the pH of these materials range from 4.2 to  The coal i s coking grade bituminous with an average s u l f u r content of 0.3  to 0.4% (Berdusco and M i l l i g a n , 1977). Two major vegetation types occur within the study area: the v a l l e y bottom to mid-mountain forest-grassland complex and above roughly 1,800 m the subalpine forest-grassland complex.  Forests at lower elevations are dominated by  Douglas f i r , lodgepole pine and western larch (Larix o c c i d e n t a l i s N u t t . ) .  Lodge-  pole pine dominates in the more recently burned, d r i e r s i t e s with Douglas f i r and p a r t i c u l a r l y larch more common on cooler aspects and seepage s i t e s .  Common  understory shrubs include s o o p o l a l l i e (Shepherdia canadensis (L.) N u t t . ) , f a l s e box (Pachystima myrsinites (Pursh) R a f . ) , honeysuckle (Lonicera utahensis Wats.) and bunchberry (Cornus canadensis  L.).  Krajina (1965) mapped t h i s area under the boreal white and black spruce biogeoclimatic zone.  However, i t seems more l o g i c a l to regard i t as the wet sub-  zone of the i n t e r i o r Douglas f i r biogeoclimatic zone.  Rowe (1972) c l a s s i f i e d  t h i s area as part of the Southern Columbia forest region.  He indicated that  along gradients of decreasing moisture more t y p i c a l l y coastal species give way to Douglas fir-western larch and lodgepole pine.  This represents the t r a n s i t i o n  from the red cedar (Thuja p l i c a t a Donn.) and western hemlock (Tsuga hererophylla (Raf.) Sarg.) forest around Fernie, B.C. to that surrounding Sparwood. Grasslands form a s i g n i f i c a n t portion of the zone near Sparwood. grasslands  These  tend to dominate on southwest facing slopes at mid to high elevations  and increase in area toward the dry v a l l e y bottom.  Those below 1,350 m represent  the primary winter ungulate range of the region (Courtney,  1977).  Both species composition and p r o d u c t i v i t y of these grasslands vary with elevation.  H i l l s i d e communities near the v a l l e y f l o o r (1,000 m) are dominated  25 by Canada bluegrass (Poa compressa L.) and timothy (Phleum pratense L.).  Heavily  overgrazed areas have been invaded by the annual cheatgrass (Bromus tectorum L.) and the biennial hop clover ( T r i f o l i u m agrarium L . ) .  Occasional patches of blue-  bunch wheatgrass (Agropyron spicatum (Pursh) Scribn. and Smith), Idaho fescue (Festuca idahoensis Elmer) and slender wheatgrass (Agropyron caninum (L.) Beauv.) may s t i l l be found.  This degeneration of the native range was probably  due to the combination of domestic grazing, f i r e and w i l d ungulate grazing over the l a s t 80 years.  These areas also support numerous shrub species:  service-  berry (Amelanchier a l n i f o l i a N u t t . ) , Douglas maple (Acer glabrum T o r r . ) , snowbrush (Ceanothus velutinus Doug!.) and others.  Most shrub species show signs of  heavy browsing. With increasing elevation the native perennial grasses become.more dominant and the influence of the introduced species i s less apparent.  A l s o , moun-  tain brome (Bromus carinatus H. & A.) and Hood's sedge (Carex hoodii Boott) become important components of the grasslands.  The major forbs in t h i s area  are balsamroot (Balsamorhiza s a g i t t a t a (Pursh) N u t t . ) , s i l k y lupine (Lupinus sericeus Pursh) and purple aster (Aster conspicuus L i n d l . ) .  These grasslands  around 1,600 m are probably the most productive on the Kaiser property. For the purpose of t h i s study and i n the i n t e r e s t of s i m p l i c i t y t h i s zone, from 1,000 to 1,800 m, w i l l be referred to under the general term, montane. The subalpine zone extends from 1,800 to 2,130 m.  This range includes  those areas dominated by subalpine f i r and Engelmann spruce. also a s i g n i f i c a n t component of forests in t h i s zone.  Lodgepole pine i s  Understory shrubs include:  grouseberry (Vaccinium scoparium Leiberg), f a l s e azalea (Menziesia ferruginea Smith.) and white rhododendron (Rhododendron a l b i f l o r u m Hook.).  Grasslands in  this zone are s i m i l a r to the upper montane in species composition although they are somewhat less productive.  Dominant species are:  bluebunch wheatgrass,  slender wheatgrass, Idaho fescue, s i l k y lupine and s u l f u r buckwheat (Eriogonum umbel!atum T o r r . ) .  26 S o i l s of the study area consist of b r u n i s o l s , l u v i s o l s and podzols. Native grasslands generally occur on e u t r i c Brunisols with thin (0-5 cm) L, F, H horizons, thick (25 cm +) Ah horizons, Ae horizons are not apparent and the B horizons are characterized by clay accumulation. Brunisols are common with thick L, F, H  Under f o r e s t vegetation d y s t r i c  horizons, no Ah and a Bfh horizon ex-  tending as much as 40 cm beneath the surface.  Podzols had been reported p r i o r  to mining on subalpine, forested s i t e s . 4.2  EXPERIMENTAL DESIGN Four areas were examined in t h i s study: montane and subalpine reclaimed  areas and adjacent native grasslands (Figure 4).  These s i t e s were p a r t i t i o n e d  into shoot, root, d e t r i t u s and s o i l compartments to allow examination of the major pathways of intra-and extra-plant nutrient exchange and storage. shoot and d e t r i t u s samples were obtained by c l i p p i n g . tained a l l above-ground l i v i n g t i s s u e s .  Both  The shoot compartment con-  Only two species on the native s i t e s :  rose (Rosa sp.) and serviceberry had a e r i a l penennating structures. these were small (ca. 10 cm t a l l ) and rare. tered i t was included in the shoot sample.  However,  When such an i n d i v i d u a l was encounThe d e t r i t u s sample included a l l  dead standing and f a l l e n shoot materials as well as other surface organic matter (ungulate droppings, dead insects) longer than 5 mm. obtained to a maximum depth of 24 cm from s o i l cores.  Root and s o i l samples were Roots were separated from  s o i l by immersion of the e n t i r e sample in a beaker of water, s t i r r i n g and r e peatedly removing the f l o a t i n g roots. possible.  V i r t u a l l y complete root recovery was thus  Core depth was noted for each sample.  roots by sieving and hand separation. N, NO^ and a v a i l a b l e P, Ca and Mg. Bicarbonate e x t r a c t i o n .  S o i l samples were cleaned of  They were then analyzed for toal (Kjeldahl)  A v a i l a b l e P was estimated by Olsen's sodium  Since the s o i l s were neutral to basic t h i s seemed more  appropriate than the Bray technique which i s more applicable to acid s o i l s . A l l plant and d e t r i t u s samples were weighed, total N, P, K, Ca and Mg.  ground and analyzed for  A l l samples were dried for 48 hours at 50 C immediately  27  Figure 4 .  Map of the study area showing the r e l a t i v e locations of the t e s t p l o t s .  28  29 after collection.  The s o i l and plant analyses were, done in the University of  B r i t i s h Columbia Soil Science Dept. Laboratory under the supervision of Dr. L. M. Lavkulich. Shoot, d e t r i t u s and root masses per unit area were m u l t i p l i e d by r e spective nutrient concentrations to y i e l d mass of nutrient per unit area per compartment.  S o i l nutrient masses per unit area were estimated by the following  formula: N, - 2 = (N, ,) d D S (g m ) (ppm)' X  where:  N d D S  = = = =  nutrient l e v e l s o i l density* average s o i l core depth to a maximum of 0.24 m % of s o i l sample passing a 2 mm mesh _3 * S o i l density was assumed to be 1,494,000 g m (2,000,000 lbs per acre s i x inches) The process of c o l l e c t i n g a complete set of samples took from 4 to 7  days.  Samples were taken on each of the paired plots commencing on 10 August  1976.  Further samples were c o l l e c t e d on 13-16 October 1976, 24-30 May 1977,  21-27 June 1977, 8-12 August 1977 and 11-17 October 1977. On 3 June 1977 one of the paired plots at each s i t e was f e r t i l i z e d with 13.0 g m"  2  N, 6.9 g m"  2  P and 8.3 g m"  pair was l e f t u n f e r t i l i z e d . 4.3 4.3.1  2  K as Cominco 13-16-10.  The other of the  The p l o t to be f e r t i l i z e d was randomly chosen.  THE STUDY SITES Reclaimed Areas Two reclaimed areas were included in t h i s study.  Both received i n i t i a l  reclamation treatments in 1974 and both were highly productive in 1976. Lower C seam was operated as an open-cast contour mine in the mid-1960's. It was resloped in 1974.  The reclaimed area covers 6.9 ha. at 1,550 m and i s  surrounded by a Douglas f i r - l o d g e p o l e pine f o r e s t with interspersed meadows. This s i t e i s near the upper l i m i t of the montane zone, and subalpine plant communities can be found in nearby g u l l i e s and on.some north-facing slopes.  30 Immediately a f t e r resloping in May 1974 the area was seeded with a mix of agronomic grasses and legumes (see Table 1).  The s i t e was i n i t i a l l y broad-  cast f e r t i l i z e d with 21-0-0, 13-16-10 or 14-14-7 (%N, % P 0 , %K 0) in e a r l y 2  June of each year.  5  2  Only the i n i t i a l a p p l i c a t i o n was incorporated by harrowing  (Table 2). Table 2.  F e r t i l i z a t i o n history of Lower C seam, a p p l i c a t i o n rate i s given in g m . 2  Year  N  P  K  1974  2.32  1.11  1.20  1975  3.85  1.47  1.75  1976  4.09  1.56  1.86  Total  10.26  4.14  4.81  Lower C seam w i l l hereafter be referred to as the montane reclaimed area. The "Assembly Pad", at 2,100 m e l . was, at the s t a r t of the study, the only high-elevation reclaimed area a v a i l a b l e f o r examination.  This 4.0 ha s i t e  was leveled in 1968 for the construction of a dragline excavator.  So, though  not an overburden dump the resultant surface material was s i m i l a r to that of the mine dumps consisting of r a p i d l y decomposing calcareous shale and some sandstone with a pH of 7.5 to 8.5.  This d i f f e r e d considerably from the surface  material at the montane reclaimed area which was more acid (pH 6.0 to 5.5) and contained more coal and carbonaceous shale.  Otherwise, both study s i t e s were  on gently west-facing slopes and shared common treatment h i s t o r i e s . The Assembly Pad was resloped in 1974, was seeded to an agronomic seed mix (see Table 1), f e r t i l i z e d and harrowed in July 1974. f e r t i l i z a t i o n history of the s i t e .  Table 3 shows the  31  Table 1.  species  A e r i a l standing crop by species (kg ha -Iv) in mid-August measured annually on Kaiser Resources Ltd. reel imed areas. year  crested wheatgrass  1975 1976 1977  intermediate wheatgrass  1975 1976 1977  redtop  1975 1976 1977  meadow foxtail  1975 1976 1977  smooth brome  1975 1976 1977  orchardgrass  1975 1976 1977  red fescue  1975 1976 1977  perennial  1975 1976 1977  ryegrass timothy  "A" lagoon  Lower "C"  seam  "C"  "2" seaia  133 120 73  106 168 6  36 133 29  16 31 9  26 112 11  7  1 1 8  30 24 8  137 210 72  95 134 325  9 7 . 4  3 1  14 24  14 50 50  21  4 92 2  3  9 18  2 118  13 35  5  22  17  1  Assembly  pad  2  56 4 30 300 147  19 146 140  119 122 72  30 32 32  36 48 36  5 2 2 10 57 167  5 8 4  55 55 38  19 14 8  90 193 73  2  124 6  469 4 12  2  1975 1976 1977  19 62  kentucky bluegrass  1975 197S 1977  '  39 165 104  34 16 18  61 206 270  4 30 85  229 372 479  128 374 399  164 659 540  20 588 492  7 44 14  19 71 136  38 284 52  1 198 358  403 24 24  231 87 6  501 470 41  89 118 44  14  .18 23  4  15 334 547  41 1  30 10 2  49 15 1  301 202 4  146 226 323  4 4 1  28 89 17  2C6 71 33  110  2 2  38 13  1  4  2  1975 1976 1977  4 48 144  8 258 62  603 511 194  1090 1202 470  1189 1001 442  738 1456 890  343 1433 1289  6 67 86  1975 1976 1977  10 72  19  41 311 324  4 149 163  5  16  7  2  1  504 589 26  209 134 57  113 458 4  226 41 7  100 56 25  120 517 33  2557 2422 1152  1498 2358 1590  1401 4202 2311  33  red clover  1975 1976 1977  whita/alsike clover  1975 1976 1977  4  1975 1976 1977  123 483 575  total total  McGilvray  21 13 19  Canada bluegrass  total  Erickson  348 208 404  43  sweetclover  Baldy face  1 11 6  1975 1976 1977  alfalfa  Michel pile  1  341 54  56  7  322 524 332  6  1172 1455 752  3 1  5  574 1102 1028  8  2300 2160 1129  3  10 25  1 ">{, J. • 1406 1642  -  32 Table 3.  F e r t i l i z a t i o n history of the Assembly Pad, a p p l i c a t i o n rate i s given in g m .  Year  N  P  K  1974  2.08  1.11  1.33  1975  4.77  2.56  3.04  1976  4.09  1.56  1.86  Total  10.94  5.23  6.23  The Assembly Pad was located amid subalpine f i r , Engelmann spruce and whitebark pine f o r e s t growing on podzolic to brum'solic s o i l s .  Also present  in t h i s area were subalpine grasslands, mainly on south to west-facing slopes. For the remainder of t h i s report the Assembly Pad w i l l be referred to as the subalpine reclaimed area. These s i t e s were chosen f o r t h i s study because they were both highly productive and represented apparently successful reclamation.  Also, a e r i a l  standing crop data had been c o l l e c t e d on these areas since 1975 (Table 1). 4.3.2  Native Grasslands Two native grasslands were included in t h i s study to act as i n d i c a t o r s  of nutrient dynamics and storages in native grasslands and to serve as c l i m a t i c controls.  The l a t t e r function would prove useful in the event of extreme  f l u c t u a t i o n s in weather i . e . drought, l a t e f r o s t or e a r l y winter.  It would i n -  dicate whether the reclaimed areas were subject to greater degrees of perturbation in the event of such disturbances which are common to the i n t e r i o r mountains. Native grassland plots were chosen as near as possible to the reclaimed study areas and, l i k e the reclaimed areas, were located on west-facing slopes. The montane native grassland was located about 0.5 km from the montane reclaimed area.  I t has a westerly exposure and a 15° slope.  The s o i l i s brun-  i s o l i c and the dominant species are t y p i c a l of those previously described for  33 upper montane  grasslands.  Due to the extent of surface mining at the high elevations undisturbed subalpine grasslands were rare.  Consequently, the nearest native grassland was  about 3 km from the subalpine reclaimed area.  The s i t e faced westward on a  slope of 32° and was 90 m lower in elevation than the subalpine reclaimed area. This s i t e was near the crest of a ridge and d i r e c t l y overlooked the Elk V a l l e y . Thus, i t was subject to high winds and received minimal subsurface water flow from upslope. The dominant species on t h i s area were bluebunch wheatgrass, Idaho f e s cue, Wheeler's bluegrass (Poa nervosa (Hook.) Vasey), s i l k y lupine, serviceberry, purple aster, w i l d buckwheat and rosy pussytoes (Antennaria microphylla Rydb.) 4.4 SAMPLING This type of study required destructive sampling over a year on small (30.5 m X 7.6 m) plots and imposed several constraints on sampling.  Primarily,  both c l i p p i n g samples and p a r t i c u l a r l y root and s o i l cores had to be small to avoid damaging the plots during the study.  Consequently, sampling had to be  s u f f i c i e n t l y intense to y i e l d , with small sample p l o t s i z e s , reasonably precise estimates. Several parameters were of i n t e r e s t in t h i s study: the mean and variance of shoot, d e t r i t u s and root masses per unit area as well as the mean and variance of s o i l l e v e l s of N, P and K.  Since chemical analyses were conducted on bulked  shoot, d e t r i t u s and root samples no confidence i n t e r v a l s could be placed on t h e i r nutrient l e v e l s . At the beginning of the study there were no a v a i l a b l e estimates of variance in any of the sample parameters. a compete set of samples was unknown.  Also, the time involved in c o l l e c t i n g Too much time taken in c o l l e c t i n g a com-  plete set of samples would increase the p o s s i b i l i t y of delay due to adverse weather.  I t would also allow changes due to growth, death and decomposition  in plots according to the order in which they were sampled.  Thus, a week was  35  shoots  MONTANE NATIVE  detritus A fertilized o unfertilized  S O N 1976  D  J  F  M A 1977  M  J  f  j  A  S  0  MONTH  Figure 5.  The temporal d i s t r i b u t i o n of organic matter in shoots and d e t r i t u s . The l e t t e r ' f indicates the date of f e r t i l i z a t i o n . Each data point i s the mean of 15 observations and i s bracketed by the standard deviation of the mean.  36 Detritus masses on both f e r t i l i z e d and u n f e r t i l i z e d plots dropped by nearly 50% between August and October 1976. to 1,050 and 800 g m  Detritus l e v e l s rose by May 1977  for the u n f e r t i l i z e d and f e r t i l i z e d p l o t s , r e s p e c t i v e l y .  These increases may have been the r e s u l t of growth and death of shoot matter during the very early spring and by the addition of elk and deer droppings. and elk herds congregated on such open areas during this period. pings were frequently encountered during the May sample.  Deer  Indeed, drop-  Another period of  rapid decomposition followed from May to June lowering d e t r i t a l masses to around _2 570 g m .  Death of recently produced shoot matter probably accounted f o r the  r i s e in d e t r i t a l l e v e l s to 690 g m  by August while decreased shoot production  and rapid decomposition resulted in d e t r i t u s losses by October.  Here, for the  f i r s t time, f e r t i l i z a t i o n e f f e c t s become apparent in decreasing d e t r i t u s l e v e l s -2  on the f e r t i l i z e d p l o t to 356 g m  -2  versus 570 g m  on the u n f e r t i l i z e d plot  (Figure 5). These data indicate two major periods of net d e t r i t u s loss (via decomposition and/or grazing): l a t e summer and early summer. during the winter and early spring as well as mid-summer.  Detritus accumulated That f e r t i l i z a t i o n  resulted in a net loss of d e t r i t u s despite increased inputs from shoot matter was probably due to accelerated decomposition. In October 1976 the root mass on the f e r t i l i z e d p l o t was somewhat ( s i g n i f i c a n t only at the 80% confidence l e v e l ) lower than that of the u n f e r t i l i z e d plot.  By the end of the study both l e v e l s were equal, suggesting a s l i g h t i n -  crease in root mass due to f e r t i l i z a t i o n (Figure 6). 5.1.2  Montane Reclaimed Area Shoot dynamics on the reclaimed area d i f f e r e d from those of- the native  area in several respects. mass u n t i l l a t e in 1976. tops.  F i r s t , the reclaimed areas maintained a large shoot This resulted in observable f r o s t k i l l i n g of some plant  Delay in the onset of f a l l dormancy due to f e r t i l i z a t i o n was also evident  in October 1977 where the f e r t i l i z e d p l o t rebounded a f t e r the drought with  37  3500  MONTANE native reclaimed  3000  fertilized o  tn •P O O  unfertilized  2500  u  o  ~  2000|  'e Cn •p  x:  CP •H 0)  1500  ><  M  1000  500  A  S O 1976  N  D  J  F  M 1977  A  M  J f  J  A  S  MONTH  Figure 6.  The temporal d i s t r i b u t i o n of organic matter in roots. The l e t t e r ' f indicates the date of f e r t i l i z a t i o n . Each data point i s the mean of 30 observations and i s bracketed by the standard deviation of the mean.  38  increased growth while the u n f e r t i l i z e d p l o t continued to lose shoot mass ( F i g ure 7).  As t h i s tendency to carry a greater shoot mass into October was also  observed on the native f e r t i l i z e d plots i t seems that f e r t i l i z a t i o n can delay the onset of f a l l dormancy i n native species as well as i n agronomic species. Thus, what appeared in 1976 to be i l l - a d a p t i v e phenological responses to c l i m a t i c signals in the agronomic species were, at l e a s t p a r t l y , due to f e r t i l i z a t i o n practices.  Second, while both native plots produced less shoot mass than in  1976 they did not display the severe decline in shoot production evident in the reclaimed plots due to the mid-summer drought.  This was probably due to the i n -  creased s o i l moisture holding capacity of the native areas as well as species tolerance to drought.  Even within the reclaimed plant community differences i n  species drought tolerance were observed.  While orchardgrass  (Dactylis glomerata  L.), timothy and the true clovers ( T r i f o l i u m spp.) were often k i l l e d to the ground; smooth brome (Bromus inermis Leys.), crested wheatgrass desertorum Fisch..), intermediate wheatgrass  (Agropyron  (A. intermedium (Host.) Beauv.),  Canada bluegrass, red fescue (Festuca rubra L.) and a l f a l f a (Medicago s a t i v a were apparently healthy throughout t h i s period.  L.)  However, a f t e r the rains of  early August orchardgrass rebounded remarkably w e l l .  No drought k i l l i n g was  apparent on the native area. Like the montane native area the montane reclaimed area l o s t d e t r i t u s from August to October 1976 while d e t r i t u s increased from October to May.  Again, as  in the native area, deer and elk p e l l e t s were abundant in the May sample at l e a s t p a r t i a l l y accounting f o r the r i s e in d e t r i t u s l e v e l s .  With the onset of the  growing season, d e t r i t u s levels f e l l on the u n f e r t i l i z e d p l o t while remaining constant on the f e r t i l i z e d p l o t . position.  F e r t i l i z a t i o n should have accelerated decom-  Maintenance of this high d e t r i t u s level resulted from an increase in  shoot inputs s u f f i c i e n t to y i e l d a s l i g h t net increase in d e t r i t u s mass. i l i z a t i o n resulted in no net increase in shoot mass from May to June.  Fert-  Thus, i t  seems the increased shoot production had been d r o u g h t - k i l l e d and entered the  39  MONTANE RECLAIMED shoot  500  detritus  cn •P  •A M •P (U  TJ  400  *  fertilized  °  unfertilized  TJ  C  (0 cn •P O  o  Xi  cn  M-l O  300  e CP -p  200  •A <D  3  >i  U  TJ  100  MONTH gure 7.  The temporal d i s t r i b u t i o n of organic matter in shoots and d e t r i t u s The l e t t e r ' f indicates the date of f e r t i l i z a t i o n . Each data poi i s the mean of 15 observations and i s bracketed by the standard deviation of the mean.  40 d e t r i t u s compartment.  The s i m i l a r i t y of shoot masses in the f e r t i l i z e d and un-  f e r t i l i z e d plots in June suggests that factors other than nutrients were l i m i t i n g . Throughout the mid-summer drought d e t r i t u s accumulated in the u n f e r t i l i z e d p l o t to match that of the f e r t i l i z e d p l o t which was v i r t u a l l y unchanged from June. By October both p l o t s l o s t considerable d e t r i t u s with the f e r t i l i z e d p l o t somewhat lower than the u n f e r t i l i z e d p l o t (Figure 7). Differences in root masses between f e r t i l i z e d and u n f e r t i l i z e d plots were not highly s i g n i f i c a n t .  However, the u n f e r t i l i z e d p l o t , a f t e r June 1977, sup-  ported a larger root mass for the duration of the study.  The root dynamics of  the montane reclaimed area resembled those of the montane native area in highly dampened form.  So, while the periods of growth and a t t r i t i o n were s i m i l a r , the  reclaimed area root systems were not nearly as productive as the native area and consequently returned much less organic matter to the s o i l each f a l l 5.1.3  (Figure 6).  Subalpine Native Grassland The response of the subalpine native area to f e r t i l i z a t i o n was s i m i l a r to  that of the montane native area.  However, in addition to greater shoot product-  i v i t y on the montane native area i t d i f f e r e d from the subalpine native area in that the f e r t i l i z e d p l o t reached maximum p r o d u c t i v i t y in June whereas the high elevation f e r t i l i z e d p l o t achieved maximum shoot production in August.  As on the  montane native area f e r t i l i z a t i o n of the subalpine native area resulted in maintenance of a larger l i v i n g shoot mass into October (Figure 8). Detritus l e v e l s on the f e r t i l i z e d and u n f e r t i l i z e d plots varied e r r a t i c a l l y in t h i s area.  The onset of the growing season brought on rapid depletion of  d e t r i t u s so that by June f e r t i l i z e d and u n f e r t i l i z e d plots had only 440 and 315 _2 g m respectively. Over the mid-summer period d e t r i t u s accumulated on the un_2 f e r t i l i z e d p l o t r i s i n g to 520 g m  while f e r t i l i z a t i o n resulted in a s l i g h t de-  crease in d e t r i t u s on the f e r t i l i z e d plot by August (Figure 8). As in the montane native area root masses on this area reached the yearly {  nadir in the l a t e f a l l and maximal levels in mid-June.  While shoot l e v e l s were  41  shoot detritus ^  fertilized unfertilized  0  900  SUBALPINE  NATIVE  cn 3 •P u  p (D TJ  750  TJ C ID  tn P  o o  X.  600  cn  M-l  O  CN  I  e  450  -p tn •H  0)  >i >-i TJ  300  150  S  M  O  A  1977  1976  M  J  J f  MONTH  Figure 8.  The temporal d i s t r i b u t i o n of organic matter in shoots and d e t r i t u s . The l e t t e r f indicates the date of f e r t i l i z a t i o n . Each data point i s the mean of 15 observations and i s bracketed by the standard dev i a t i o n of the mean. 1  42 higher on the montane native area the subalpine native area produced a larger root mass.  Thilenius (1975), working in subalpine areas of the Medicine Bow  Mountains of Wyoming measured root masses from l a t e June to late August. _2  Within  t h i s period root masses ranged from 2,729 to 7,186 g m .  (Bliss,  Other workers  1963; Scott, 1963) reported root masses ranging from 750 to 3,634 g m ious alpine plant communities.  in var-  So, while the root masses of high-elevation plant  communities are highly variable the data presented here f a l l within the range of reported values (Figure 9). 5.1.4  Subalpine Reclaimed Area Substantial overwinter shoot loss occurred on both reclaimed areas.  Otherwise, shoot masses on the two reclaimed areas behaved quite d i f f e r e n t l y . While the montane area l o s t nearly half of i t s shoot mass between June and August due to drought, the subalpine area showed no such depression.  Indeed, while  summer drought negated f e r t i l i z e r e f f e c t s u n t i l October on the montane area, f e r t i l i z a t i o n had a dramatic e f f e c t on shoot production on the subalpine area nearly quadrupling shoot mass by August (Figure 10).  This difference was due to  a more favorable s o i l moisture environment. Among the four study areas d e t r i t a l dynamics on the subalpine reclaimed area were unique.  Of p a r t i c u l a r s i g n i f i c a n c e was the tendency of the u n f e r t -  i l i z e d p l o t to accumulate d e t r i t u s . d e s p i t e lowered shoot production from the previous year.  Indeed, d e t r i t u s nearly doubled on the u n f e r t i l i z e d p l o t from _2  October 1976 to October 1977 while August shoot levels were 87 g m 1977.  lower in  This suggests rapid shoot a t t r i t i o n during the growing season and slow  decomposition.  Also, detritus on a l l other u n f e r t i l i z e d plots underwent two  major periods of net loss (early f a l l and early summer) as well as two periods of net accumulation (winter to early spring and mid-summer).  The subalpine r e -  claimed area l o s t d e t r i t u s only in mid-summer while accumulating d e t r i t u s during the remainder of the year (Figure 10).  This d e t r i t a l accumulation represents  a sink for the more slowly a v a i l a b l e nutrients and w i l l r e s u l t in s i g n i f i c a n t  43  SUBALPINE native  S  O  N  D  J  1976  F  M  A 1977  M  J f  J  A  S  MONTH Figure 9.  The temporal d i s t r i b u t i o n of organic matter in roots. The l e t t e r ' f indicates the date of f e r t i l i z a t i o n . Each data point i s the mean of 30 observations and i s bracketed by the standard deviation of the mean.  44  SUBALPINE RECLAIMED . shoot tn D P •H H -P <D TJ TJ C  rO  tn P 0 O J3 tn  m O  detritus  500  fertilized unfertilized 400  300  •P •i-t  200  TJ  100  A  S  O  N  D  J  1976  M A M 1977  J  f  J  A  MONTH Figure 10.  The temporal d i s t r i b u t i o n of organic matter in shoots and d e t r i t u s . The l e t t e r ' f indicates the date of f e r t i l i z a t i o n . Each data point i s the mean of 15 observations and i s bracketed by the standard deviation of the mean.  45 losses from the a v a i l a b l e nutrient pools.  At the l e a s t , unchecked accumulation  w i l l cause formation of an i n s u l a t i n g mat which in t h i s cold environment w i l l lower surface temperatures, further retarding decomposition. The root system of the subalpine reclaimed area was in the early stages of development.  The slow but constant increase in root mass u n t i l the end of the  study suggests young root material that was only beginning to undergo s i g n i f i c a n t fall attrition.  Indeed, although both subalpine and montane reclaimed areas  were i n i t i a l l y seeded in 1974 the subalpine area root system seemed to be a year "behind" that of the montane area.  Also, unlike the montane reclaimed area the  root mass of the subalpine area showed a s l i g h t increase due to f e r t i l i z a t i o n . Both reclaimed areas, regardless of f e r t i l i z e r treatment, reached peak root standing crop l e v e l s in August whereas the native areas root masses peaked in late June (Figure 9). the  Whether t h i s was due to d i f f e r e n t l i f e cycle timing in  agronomic species or to s o i l factors (nutrient m i n e r a l i z a t i o n ,  i s unclear.  supply)  It i s clear that root systems of the native communities constituted  a much greater storage f a c i l i t y for carbohydrates and nutrients and contributed more organic matter to the s o i l in annual a t t r i t i o n than the reclaimed area root systems.  This would permit greater i n - p l a n t carbohydrate and n u t r i e n t c y c l i n g  and provide massive organic matter inputs to the s o i l , improving s o i l structure and cation exchange capacity.  Of course, the reclaimed areas as young communities  could not match the root development of mature, native communities in only four years. 5.2  NET CHANGES IN ORGANIC MATTER Tables 4 and 5 represent balance sheets i n d i c a t i n g periods of net accumu-  l a t i o n and loss of organic matter in the shoot, d e t r i t u s and root compartments. The bottom l i n e of each section indicates net change within compartment from October 1976 to October 1977. Most of the organic matter turnover on native areas occurred in the root systems and to a much lesser extent in the d e t r i t u s and shoot compartments.  This  46 Table 4.  Net change in oven dry organic matter (g m~ ) between sampling dates. The l e t t e r s ' F ' and 'NF' indicate f e r t i l i z e d and unf e r t i l i z e d plots r e s p e c t i v e l y .  shoot  d e t r i tus  root  total  Aug/Oct  -255.5  -302.1  -486.5  -1044.1  Oct/May  -14.5  353.3  -194.6  144.2  May/June  192.9  -267.0  2380.7  2306.6  June/Aug  6.5'  164.4  -911.9  -741.0  -156.8  -343.6  -877.9  -1378.3  28.1  -92.2  396.3  311.5  Aug/Oct  -333.7  -390.0  -490.0  -1213.7  Oct/May  2.4  556.3  -228.4  330.3  May/June  109.0  -456.9  2009.3  1661.4  June/Aug  12.7  99.5  -324.1  -211.9  -141.9  -127.3  -1280.5  -1549.7  -17.8  71.6  176.3  230.1  Montane native F  Aug/Oct total (Oct/Oct)  Montane native NF  Aug/Oct total (Oct/Oct)  Montane reclaimed F Aug/Oct  -29.2  -178.7  -436.6  -644.5  Oct/May  -76.1  167.1  392.1  483.1  May/June  94.0  4.2  121.4  219.6  June/Aug  -89.7  -4.8  23.6  -70.9  Aug/Oct  46.6  -146.1  -276.3  -375.8  -25.2  20.4  260.8  256.0  total (Oct/Oct)  Montaine reclaimed NF Aug/Oct  -43.3  -75.5  -323.9  -442.7  Oct/May  -78.3  140.6  228.4  290.7  May/June  83.6  -127.8  258.8  214.6  June/Aug  -71.6  38.8  103.7  70.9  Aug/Oct  -16.3  -113.2  -233.8  -363.3  total (Oct/Oct)  -82.6  -61.6  357.1  212.9  47 Table 5.  Net change in oven dry organic matter (g m~ ) between sampling dates. The l e t t e r s ' F ' and 'NF' indicate f e r t i l i z e d and unf e r t i l i z e d plots respectively.  shoot  d e t r i tus  root  total  Subalpine native F Aug/Oct  -154.8  46.0  -763.6  -872.4  Oct/May  8.8  247.6  2672.0  2928.4  May/June  99.3  -331.6  291.5  59.2  June/Aug  44.5  -24.9  -501.1  -481.5  Aug/Oct  -90.0  -202.2  -1999.1  -2291.3  62.6  -311.1  463.3  214.8  total (Oct/Oct)  Subalpine native NF Aug/Oct  -86.3  -179,6  -672.9  -938.8  Oct/May  -12.6  17.1  1134.6  1139.1  May/June  78.6  -169.6  1701.1  1610.1  June/Aug  -27.3  204.9  -1061.2  -883.6  Aug/Oct  -96.9  -250.1  -1331:6  -1698.6  total (Oct/Oct)  -58.2  -197.7  422.9  167.0  Subalpine reclaimed F Aug/Oct  -159.9  156.6  23.4  20.5  Oct/May  -108.0  9.8  120.5  23.3  May/June  138.1  114.6  144.2  396.9  June/Aug  262.8  -7.1  222.8  478.5  Aug/Oct  -64.2  -144.7  -97.3  -306.2  total (Oct/Oct)  228.7  -27.4  390.2  592.5  Subalpine reclaimed NF Aug/Oct  -70.6  111.3  21.9  62.6  Oct/May  -99.2  73.3  77.8  51.9  May/June  95.8  97.4  120.2  313.4  June/Aug  -12.2  -67.6  107.1  27.3  Aug/Oct  -19.9  19.1  -118.5  -119.3  total (Oct/Oct)  -35.5  122.2  186.6  273.3  48 pattern was consistent regardless of f e r t i l i z e r treatment.  On the reclaimed  areas most of the organic matter turnover also occurred v i a the root system thought the surface d e t r i t u s pathway was nearly as s i g n i f i c a n t .  Except for  the drought-impaired montane reclaimed area, f e r t i l i z a t i o n resulted in a large increase in shoot production.  Although this increased inputs to the d e t r i t u s  compartments, d e t r i t u s losses were usually greater on the f e r t i l i z e d plots i n dicating accelerated decomposition. The montane reclaimed area was again the exception where, despite s i m i l a r shoot standing crops in May and August, the u n f e r t i l i z e d p l o t l o s t considerable detritus  while the f e r t i l i z e d p l o t underwent l i t t l e change in d e t r i t u s l e v e l .  This was due to increased shoot production on the f e r t i l i z e d p l o t which was rapidly d r o u g h t - k i l l e d , maintaining s i m i l a r shoot standing crops while c o n t r i buting s u b s t a n t i a l l y to the rapidly-decomposing d e t r i t u s pool. While root masses on a l l plots increased over the year the increase was generally greatest on the f e r t i l i z e d p l o t s .  The f e r t i l i z e d montane native p l o t  root mass increased 125% more than on the u n f e r t i l i z e d p l o t while the subalpine reclaimed f e r t i l i z e d p l o t measured a 109% greater net increase in root mass over the u n f e r t i l i z e d p l o t from October 1976 to October 1977.  Over the same period  f e r t i l i z a t i o n resulted in only a 10% increase in net root mass accumulation in the subalpine native area.  However, on the montane reclaimed u n f e r t i l i z e d p l o t  the rate of root mass accumulation was 37% greater than that of the f e r t i l i z e d plot. Again, t h i s aberrant behavior in the montane reclaimed area was probably due to drought e f f e c t s .  The data of Table 4 show that most of the root mass gains  on the f e r t i l i z e d p l o t were made between October 1976 and May 1977.  From May  to June root mass increase on the f e r t i l i z e d p l o t was only 4% of that recorded for the u n f e r t i l i z e d p l o t and during the June to August t h i s dropped further to 23%.  This suggests that f e r t i l i z a t i o n may have upset the system by inducing  greater shoot growth than could be supported by s o i l moisture supplies.  This  49 represents a wastage of carbohydrate resources, apparently at the expense of the root system. No such e f f e c t was evident on the subalpine reclaimed area where e f f e c t s of the drought were minimal.  Indeed, the subalpine reclaimed f e r t i l i z e d p l o t  showed the l a r g e s t net gain in the three measured compartments of a l l the study areas.  While most of t h i s gain was in root mass a large portion was in shoot  mass which by mid-October was probably a l i a b i l i t y rather than an asset since f r o s t k i l l i n g transferred most of i t s carbohydrates and nutrients to the d e t r i t u s pool before translocation to the root system could occur. Conversion of the data presented in the previous two tables into g m day ~* allows c l o s e r examination of peak net p r o d u c t i v i t y and loss periods as well as comparison with net p r o d u c t i v i t y data gathered in other studies.  Addi-  tion of net shoot and root accumulation estimates net primary p r o d u c t i v i t y minus grazing and losses due to senescence of plant material. Perhaps the most s t r i k i n g figures are those for May to June net production in the native areas, p a r t i c u l a r l y the montane native area.  In t h i s period on the  -2 -1 f e r t i l i z e d p l o t shoot mass accumulated at 5.5 g m day while root mass accum-2 -1 ulated at 68.0 g m day . This gives an estimated net primary p r o d u c t i v i t y - 2 - 1 of 73.5 g m day which i s very near the estimated maximum rate of net primary -2 -1 production of 77 g m  day  proposed by Loomis and Williams (1963).  The mon-  tane native u n f e r t i l i z e d p l o t during the same period showed net shoot and root - 1 mass accumulations of 3.1 and 57.4 g m- 2 day for a t o t a l of 60.5 g m-2 day -1 These data not only indicate an extremely high rate of net production for this short period but also i n d i c a t e the photosynthetic demands imposed by the large annual turnover within these perennial root systems.  Indeed, turnover of net  annual root production averaged 77% in the montane and 85% in the subalpine native areas.  Comparable figures for the reclaimed areas were 51% in the montane r e -  claimed f e r t i l i z e d p l o t and 40% in the montane reclaimed u n f e r t i l i z e d p l o t . subalpine reclaimed area turnover rates were 20 and 39% respectively for the  The  50 f e r t i l i z e d and u n f e r t i l i z e d p l o t s . Thus, f o r montane native, montane reclaimed, subalpine native and subalpine reclaimed areas an average of about 1,910; 205; 2,450; and 108 g m roots respectively were returned to the s o i l in 1977.  of  These figures represent  minimum inputs as the sampling procedure only recorded net changes in root mass and would conceal, for example, root senescence, exudation and sloughing periods of rapid root growth.  during  S t i l l , the data indicate the extent to which even  the small root masses of the reclaimed areas influence s o i l development through organic matter inputs.  In r e l a t i o n to the cost of a r t i f i c i a l l y d i s t r i b u t i n g and  incorporating 1.0 to 2.5 t ha~* of high-quality organic matter this root t u r n over i s highly s i g n i f i c a n t . 5.3 5.3.1  NUTRIENT CONCENTRATIONS Nitrogen Shoot N concentration tended to decline s l i g h t l y in the f a l l of 1976, then  r i s e to a yearly maximum in May or June, decline throughout the summer and r i s e s l i g h t l y by October 1977.  (See Appendix VIII for a l l nutrient concentrations).  F e r t i l i z a t i o n tended to move the period of peak N concentration from l a t e May to l a t e June and to maintain higher shoot N concentrations throughout the summer. Shoot N concentration on a l l u n f e r t i l i z e d p l o t s , native and reclaimed, varied with a s i m i l a r pattern and within a s i m i l a r range.  Generally, on the u n f e r t i l i z e d  plots yearly minima were between 0.6 and 1.0% while yearly maxima were between 2.0 and 3.0%.  The subalpine reclaimed u n f e r t i l i z e d p l o t tended to have s l i g h t l y  lower shoot N concentrations than the subalpine native p l o t throughout the study. The montane reclaimed u n f e r t i l i z e d had the lowest minimum and highest maximum value of any u n f e r t i l i z e d p l o t .  The subalpine reclaimed f e r t i l i z e d p l o t under-  went the most pronounced r i s e in shoot N concentration, more than doubling that of the u n f e r t i l i z e d p l o t . On the montane areas d e t r i t u s N concentration varied between 1.0 and 2.0% throughout the study.  Peak d e t r i t u s N concentration in the native area occurred  51 in October 1977.  However, on the reclaimed area the d e t r i t u s N concentration  peaked in l a t e June on the u n f e r t i l i z e d plot and in August on the f e r t i l i z e d plot.  This suggests that s i g n i f i c a n t amounts of shoot N were added to the f e r t -  i l i z e d p l o t d e t r i t u s pool during the mid-summer drought or that t h i s N was not rapidly mineralized.  On the montane areas d e t r i t u s N concentrations varied  between 1.0 and 2.0%. Detritus N concentrations on the subalpine areas tended to be lower than on the montane areas.  Values ranged between 0.4% and 1.6%.  The native area  generally had higher d e t r i t u s N concentrations than the reclaimed area. In contrast to shoot and d e t r i t u s N concentrations root N concentrations tended, with a few exceptions, to remain nearly constant throughout the study. F e r t i l i z a t i o n increased root N concentrations in the subalpine native area while ultimately y i e l d i n g a s l i g h t increase in the montane native area.  Fertilization  increased the root N concentration during the summer on the subalpine reclaimed area but by October 1977 root N concentrations were s i m i l a r on both f e r t i l i z e d and u n f e r t i l i z e d p l o t s . The most s t r i k i n g aspect of the root N concentrations through time was t h e i r lack of seasonal response.  Thus, l i t t l e net translocation of N to the  overwintering portions of the root systems occurred. native and reclaimed areas.  This was true f o r both  It was expected that s i g n i f i c a n t net translocation  would occur from both senescing shoot and root matter.  So i t becomes apparent  that these plant communities possess an open-ended e x t r a - b i o t i c N cycle (Switzer and Nelson, 1972) or, N cycles from the plant through the decomposition system and, to some extent, back to the plant again in the spring.  This suggests that,  rather than maintaining a large, mobile store of N in the roots over winter for use in the spring-early summer growth period, the plants take most of t h e i r yearly N requirements from the mineralized N in the s o i l each spring. The native areas maintained higher root N concentrations than the reclaimed areas.  Also, the montane reclaimed area maintained a higher N concentration  52 than the subalpine reclaimed area.  Although not apparent from the root N con-  centration data, the mass of the native area systems over winter was much greater than on the reclaimed areas.  Thus, the native areas possessed a larger root  system with which to e x p l o i t mineralized N in the c r i t i c a l spring-early summer period.  In a d d i t i o n , the N concentration of senesced root material was high so  that i t probably decomposed r a p i d l y in spring and, thus, represented a s i g n i f i cant a v a i l a b l e M reserve. 5.3.2  Phosphorus Unlike shoot N, shoot P concentrations increased on the montane areas  between August and October.  The exception was the native f e r t i l i z e d p l o t which,  in the f a l l a f t e r f e r t i l i z a t i o n , f a i l e d to concentrate shoot P.  The subalpine  native area also concentrated shoot P i n the f a l l while on the subalpine reclaimed area shoot P concentration tended to drop toward October.  Shoot P concentration  tended to reach a yearly maximum of between 1.30 and 0.40% in October which continued u n t i l May.  With the onset of rapid shoot growth shoot P concentration  decreased to a minimum in August.  F e r t i l i z a t i o n tended to increase shoot P con-  centration s l i g h t l y . Detritus P concentrations tended to remain stable between 0.10 and 0.30%. On the montane areas d e t r i t u s P concentration tended to be higher than on the subalpine areas.  The concentration of detritus P tended to be highest in October  when the remainder of the y e a r ' s shoot production was added, and at a minimum between May and June when decomposition was greatest.  A f t e r dropping in August  and October 1976, the d e t r i t u s P concentration on the subalpine reclaimed area remained v i r t u a l l y constant for the remainder of the study. Root P concentrations, l i k e those of shoot P tended to increase on every p l o t except the subalpine reclaimed during the f a l l of 1976, decrease to a yearly minimum between May and June of 1977, then slowly r i s e again toward October. F e r t i l i z a t i o n had no apparent e f f e c t on root P concentration except to depress i t s l i g h t l y during the summer.  53 That root P concentration showed less net increase in the f a l l of 1977 than i n the f a l l of 1976 may have been a r e f l e c t i o n of the dry summer of 1977. In contrast, the summer of 1976 was r e l a t i v e l y wet for the region.  Thus, i n a  wet year more shoot matter survives u n t i l f a l l and i t s P i s a v a i l a b l e for t r a n s location to the roots and perennating shoots. conservative than that of N.  Indeed, the P cycle was much more  In these communities i t would be c l a s s i f i e d as  " b i o t i c " i n contrast to the " extra b i o t i c " N c y c l e .  Nonetheless, large amounts  of P cycle through the detritus-decomposer system as evinced by the increases in d e t r i t a l P concentrations in f a l l .  Nonetheless, the f a c t that both perennating  shoots and roots concentrated P toward f a l l suggests that i t was more mobile within the plant than N and that i t was s e l e c t i v e l y conserved by the plants. The subalpine reclaimed area was unique i n i t s apparent lack of P conservation in the f a l l of 1976 when both shoot and root P concentrations declined.  Both  plots had been f e r t i l i z e d that year and growth conditions were favorable with abnormally high r a i n f a l l throughout the summer.  The combination of these factors  resulted in maintenance of a large shoot standing crop into October when f r o s t k i l l e d most of the green shoots before translocation could occur.  In f a c t , during  the October sample f r o s t k i l l i n g of green shoots was evident on t h i s area. 1977, however, the lack of rain in mid-summer, while r e s u l t i n g in l i t t l e  In  drought  damage, may have induced e a r l i e r senescence than in the previous year. 5.3.3  Potassi urn Shoot K concentrations varied widely over the study period.  Nonetheless,  a pattern emerged over the year though i t s implications were not e n t i r e l y c l e a r . On the native areas shoot K concentrations dropped during the f a l l of 1976 and rose s u b s t a n t i a l l y by spring.  Then a sharp r i s e occurred in the montane native  f e r t i l i z e d area while on the subalpine native area the u n f e r t i l i z e d p l o t showed the sharpest r i s e in shoot K concentration.  Shoot K concentrations then f e l l so  that concentrations were equal on a l l native plots by August.  By October the data  again diverged so that the montane native f e r t i l i z e d plot l o s t while the u n f e r t i l i z e d  54 p l o t gained in concentration.  The opposite occurred on the subalpine native  area so that the p l o t which concentrated the most in shoot K between May and June continued to decline in shoot K concentration u n t i l October.  Why the de-  c l i n e occurred on the f e r t i l i z e d p l o t at low elevation and on the u n f e r t i l i z e d plot at high elevation i s unclear. On the reclaimed areas shoot K concentrations tended to increase in the f a l l of 1976 and remain constant through the winter. both montane reclaimed plots were equal.  By June concentration on  Then, both f e l l by August and rose  again by October to the previous October l e v e l s .  From August u n t i l October 1977  the f e r t i l i z e d p l o t maintained a higher shoot K concentration.  On the subalpine  reclaimed area f e r t i l i z a t i o n resulted in a rapid increase in shoot K concentration but a f t e r June, on both f e r t i l i z e d and u n f e r t i l i z e d p l o t s , shoot K concentration declined s t e a d i l y u n t i l October. Detritus K concentration tended to r i s e between August and October, drop to a minimum by spring then r i s e slowly by October again.  The f a l l r i s e in de-  t r i t u s K concentration was most pronounced on the reclaimed areas and was probably due to delayed senescence.  On the subalpine reclaimed area, where f e r t -  i l i z a t i o n caused the maintenance of a large standing crop, enrichment of d e t r i t u s with K was evident in October of 1977.  No such e f f e c t was obvious on the montane  reclaimed area where f e r t i l i z a t i o n had l i t t l e e f f e c t on shoot standing crop. The rapid losses in d e t r i t a l K concentrations a f t e r enrichment periods indicated a rapid leaching of K from d e t r i t u s . Root K concentrations on a l l areas were very low r e l a t i v e to those of shoot and even d e t r i t u s .  Also, except for June increases on both reclaimed areas,  root K concentrations were v i r t u a l l y constant throughout the study period at about 0.15%.  F e r t i l i z a t i o n had no obvious e f f e c t on concentrations. The data indicate that K concentrated in the shoots, that i t tended to  translocate to perennating parts only on the reclaimed areas and that i t s residence time i n d e t r i t u s was very short.  Thus, K cycled " e x t r a - b i o t i c a l l y " and  rapidly.  55 Also, the inconsistent e f f e c t s of a r t i f i c a l K additions suggest the  presence of a s o i l system in the subalpine native area where added K i s somehow made unavailable.  Such a system could involve expanding-lattice clays where ad-  d i t i o n of excessive K of NH^ might convert montmorillonite to i l l i t e and, thus, +  change the i n t e r s t i t i a l K from the slowly a v a i l a b l e to unavailable form.  Since  no data are a v a i l a b l e on the clay mineralogy of these s o i l s , however, t h i s r e mains as speculation. 5.4 5.4.1  TEMPORAL DISTRIBUTION OF NITROGEN Montane Native Grassland The organic matter l e v e l s presented previously were m u l t i p l i e d by the  appropriate nutrient concentration y i e l d i n g nutrient masses per unit area in the shoot, root and d e t r i t u s compartments.  S o i l nutrient l e v e l s were converted to  mass per unit area and are also presented in the following s e c t i o n . F e r t i l i z a t i o n increased the mid-summer shoot N level by nearly 200% over the u n f e r t i l i z e d p l o t . into October.  F e r t i l i z a t i o n also caused more N to be c a r r i e d by shoots  These changes would, of course, b e n e f i t the l o c a l ungulate herds  but may adversely a f f e c t the plant community by delaying f a l l dormancy, seed set and translocation of N to the roots (Figure 11). The periods of net loss of d e t r i t a l N coincided with the end of the growing season (mid-August to mid-October) and the peak of the growing season ( l a t e May to l a t e June) (Figure 11)., The timely release of N from the large d e t r i t u s pool in June may well be c r i t i c a l in supplying the rapidly-growing plants.  Fertilization  had l i t t l e e f f e c t on the d e t r i t a l N level except by depressing i t at the very end of the study.  This probably resulted from enhanced decomposition.  F e r t i l i z a t i o n had l i t t l e e f f e c t on root N l e v e l s (Figure 12).  The s l i g h t  depression i n the f e r t i l i z e d p l o t in August 1977 may have been due to the i n creased demands of the l a r g e r shoot system.  The root systems in these native  communities consituted a very large N pool.  Since plant N i s l a r g e l y bound in  highly mobile proteins this pool i s probably to some extent a v a i l a b l e to the rapi d l y developing shoot system in the spring.  However, the large (pearly 50%)  56  17>!  montane native  montane reclaimed shoot  15  detritus  15  IO!  A  fertilized  o  unfertilized  10  3  n 0 <u t3  AS O N D J F M A M J J A S 1976 1977  0  ASON 1976  D J F M A M J J A S 1977  0  C  subalpine native  o o  subalpine reclaimed  •H  15 I  s  2  10  10  0 A  0 S O N D J F M A M J J A S O 1976 1977  Figure 11.  W  N  T  H  A S O N D J F M A M J J A S O 1976 . 1977  The temporal d i s t r i b u t i o n of N in shoots and d e t r i t u s , the l e t t e r ' f indicates the'date of f e r t i l i z a t i o n .  57  native reclaimed A  fertilized  o  unfertilized  A S O N D J F M A M J J A S O 1976 1977  A S O N D J F M A M J J A S O 1976 1977 f  MONTH  Figure 12. The temporal d i s t r i b u t i o n of root N, the l e t t e r ' f the date of f e r t i l i z a t i o n .  indicates  58 turnover of the root N indicates that the N cycle in these grasslands i s to a large extent e x t r a - b i o t i c . The root systems of t h i s grassland returned about -2 -1 21 g m (210 kg ha ) of N to the s o i l between June and October. The f l u c t u a t i o n s i n s o i l N between sampling dates were as high as 600 g _2 m  .  These differences were much higher than could be accounted f o r by plant  uptake (Figure 13).  Since even most of these differences were not s i g n i f i c a n t  at the 90% confidence level (See Appendix I) sampling error apparently masked any treatment e f f e c t s .  Sampling i n t e n s i t y was l i m i t e d by f i n a n c i a l considerations.  Unfortunately, t h i s i n t e n s i t y did not y i e l d adequately precise estimates to der i v e meaningful input-output equations.  However, the data do i n d i c a t e that  t o t a l s o i l N was very high on the montane native grassland and that inputs to the s o i l N pool from the plants or f e r t i l i z e r s were minor in comparison.  The  s i g n i f i c a n c e of the plant and f e r t i l i z e r inputs would T i e in t h e i r greater availability. S o i l n i t r a t e went through two periods of accumulation (winter-early spring and mid-summer) and two periods of depletion (early summer and early f a l l ) .  Soil  n i t r a t e accumulation and depletion coincided with periods of d e t r i t a l gain and l o s s , so f a l l i n g n i t r a t e l e v e l s occurred during periods of rapid d e t r i t a l decomposition.  The loss of s o i l n i t r a t e i n early summer resulted from the coincidence  of rapid decomposition and even more rapid plant N-uptake.  However, the early  f a l l drop in s o i l n i t r a t e was accompanied by a s i g n i f i c a n t loss in both plant and d e t r i t u s N (Figure 14).  The r i s e in s o i l n i t r a t e during winter and early  spring r e f l e c t s the loss of root mass and i t s decomposition at a time when plant uptake was minimal.  The accumulation of s o i l n i t r a t e in mid-summer also occurred  when decomposition was high yet plant uptake was low.  The loss of s o i l n i t r a t e  in early f a l l , when decomposition was high and uptake was low was probably due to leaching as r a i n f a l l was high during t h i s period and, unlike the rainy early summer period, plant uptake could not capture the released n i t r a t e . F e r t i l i z a t i o n had no clear e f f e c t on s o i l n i t r a t e l e v e l s .  The f e r t i l i z e d p l o t had higher s o i l  59  •reclaimed .native A  fertilized  0  unfertilized  1200 subalpine  montane /  •H  o  /? /I /I  900  CD  c  I  •H  I  90d  td-  CN  \  /  I  \  I  3  600  I  60 •  2  ^  A  ?  fO P O P  300  300  A S O N D J F M A M J 1976  Figure 13.  1977  f  J A S O  A S O N D J F M A M J MONTH  1976  f  J A  1977  The temporal d i s t r i b u t i o n of t o t a l s o i l N, the l e t t e r indicates the date of f e r t i l i z a t i o n .  1  f  S 0  Montane (2.9)  Subalpine  -reclaimed native  2.0 X  fertilized  o  unfertilized  2.0  1.5  1.5  1.0  1.0  0.5  0.5  A S O N D J F M A M 1976 1977 Figure 14.  J_ J  A  S  0  0 A S O N D J F M A M J J 1976 1977  A  S O  The distribution of s o i l nitrate, the l e t t e r »f indicates the date of f e r t i l i z a t i o n  61 n i t r a t e p r i o r to f e r t i l i z a t i o n and the higher level was maintained a f t e r t r e a t ment.  This suggests that the added N was r a p i d l y u t i l i z e d by plants or micro-  organisms. 5.4.2  Montane Reclaimed Area Without f e r t i l i z a t i o n shoot N l e v e l s were higher on the montane reclaimed  area than on the montane native area from May through October.  However, the native  area, unlike the reclaimed area, showed a strong response to f e r t i l i z a t i o n ure 11).  (Fig-  This was due to the mitigation of drought e f f e c t s on the native area.  M i t i g a t i n g factors could include greater moisture absorbtion and retention in the native s o i l s as well as adaptive mechanisms of the native species, for example:  greater rooting depth, u t i l i z a t i o n of the  photosynthetic pathway and  i n v o l u t i o n of stomate-bearing l e a f surfaces with attendant reduction of t r a n s piration. The higher shoot N l e v e l s on the u n f e r t i l i z e d reclaimed p l o t versus the native u n f e r t i l i z e d p l o t were probably due to the larger legume component of the reclaimed area.  The persistence of higher nutrient l e v e l s on even the unfert-  i l i z e d reclaimed area probably explains the ungulate preference for the reclaimed areas.  ' The montane reclaimed f e r t i l i z e d p l o t showed peak d e t r i t a l N levels in  August 1977 while on the u n f e r t i l i z e d p l o t d e t r i t a l N reached i t s maximum in June.  However, shoot N l e v e l s from May to August were s i m i l a r on both plots  (Figure 11).  The August peak in d e t r i t a l N on the f e r t i l i z e d p l o t may have r e -  sulted from continued growth into the drought period which could not be supported by a v a i l a b l e s o i l moisture.  On the u n f e r t i l i z e d p l o t net shoot production was  reduced during the drought.  With less shoot N input, the d e t r i t u s N pool f e l l  between June and August while d e t r i t u s N increased on the f e r t i l i z e d p l o t . Detritus N l e v e l s on both plots were s i m i l a r by the end of the study and were s u b s t a n t i a l l y below d e t r i t a l N levels on the native area.  /  62 While shoot N levels on native and reclaimed areas were s i m i l a r throughout the study, root N levels were around 6 to 10 times higher on the native areas.  So, reclaimed area root systems constituted a much smaller storage f a c -  i l i t y for N in e a r l y spring when rapid growth requires r e a d i l y accessible N. Also, the u n f e r t i l i z e d p l o t had a larger root N mass throughout the growing season in the reclaimed area (Figure 12).  This may have been due to the N de-  mands of the a r t i f i c a l l y - s t i m u l a t e d shoot mass of the f e r t i l i z e d p l o t .  Much  of the added shoot N went d i r e c t l y into the d e t r i t u s pool between June and August.  The increased shoot production apparently occurred at the expense of the  root N pool. As in the native areas, estimates of t o t a l s o i l N on the reclaimed area were imprecise due to the small sample s i z e .  Although estimated l e v e l s on the  u n f e r t i l i z e d p l o t were generally twice those of the f e r t i l i z e d p l o t the differences were s i g n i f i c a n t (at 90% confidence) only i n June and August 1977.  The data i n -  d i c a t e , however, that t o t a l s o i l N l e v e l s were lower on the reclaimed areas than on the native areas (Figure 13).  However, t o t a l soi1 N levels on the montane  reclaimed area were nearer those of the native areas than the subalpine reclaimed area.  The two reclaimed areas had d i f f e r e n t types of overburden l e f t at the  surface.  While the subalpine area was covered with calcareous shale the montane  area was surfaced with carbonaceous shale and oxidized c o a l .  This darker mat-  e r i a l i s high in organic matter and may contain large amounts of t o t a l N.  How-  ever, t h i s N i s considered to mineralize at a very low rate (Fairbourn, 1974). Since t o t a l a r t i f i c i a l N inputs during the history of t h i s s i t e were only about -2 -2 10 g m and N-fixation by legumes could account for only about 40 g m (Tisdale and Nelson, 1975b) in i t s 4 year reclamation period most of t h i s N was apparently bound in the surface m a t e r i a l . S o i l n i t r a t e on the montane reclaimed u n f e r t i l i z e d p l o t decreased slowly from August 1976 to May 1977, f e l l sharply in early summer and continued to dec l i n e toward f a l l a f t e r a s l i g h t r i s e in August.  The f e r t i l i z e d p l o t , l i k e the  63 native area, l o s t s o i l n i t r a t e in the f a l l of 1976 and accumulated n i t r a t e by spring.  With the onset of the growing season s o i l n i t r a t e decreased then rose  rapidly u n t i l October (Figure  14).  The nearly continual loss of s o i l n i t r a t e from the u n f e r t i l i z e d p l o t suggests that a new equilibrium was becoming established that would be able to supply less n i t r a t e than was previously a v a i l a b l e .  The low rate of s o i l N mineral-  i z a t i o n may be only temporary and may be reversed i f the population of decomposer microorganisms 5.4.3  increases in the future.  Subalpine Native Area Subalpine native shoot N pools were lower than on the montane area.  Even  the u n f e r t i l i z e d reclaimed p l o t had higher June shoot N levels than the subalpine native u n f e r t i l i z e d p l o t .  However, the subalpine native f e r t i l i z e d p l o t main-  tained higher shoot N levels into October than e i t h e r montane area.  The subal-  pine native u n f e r t i l i z e d p l o t had peak shoot N levels in June which quickly dropped to very low l e v e l s by October (Figure 11). Detritus N l e v e l s on the subalpine native plots were generally lower than those of the montane native p l o t s .  Like d e t r i t u s organic matter l e v e l s , d e t r i t u s  N varied i n c o n s i s t e n t l y during the study.  The difference between f e r t i l i z e d and  u n f e r t i l i z e d plots in May was p a r t i c u l a r l y anomalous (Figure  11).  Root N masses on the subalpine native area were s i m i l a r to those of the montane native area.  Maximal and minimal l e v e l s , however, were c o n s i s t e n t l y  lower on the subalpine native area (Figure 12).  Thus, a higher root N: shoot N  r a t i o was generally evident on the subalpine p l o t s .  In the spring, shoot N i n -  creased more r a p i d l y on the montane native area while root N increase was more rapid on the subalpine native area.  F e r t i l i z a t i o n resulted in a higher August  root N level but by October no f e r t i l i z e r e f f e c t on root N was apparent. Throughout the study, s o i l total N fluctuated between 360 and 750 g m (Figure 13).  Again, although standard deviations of the means were usually less  than 15% of the mean, the low sample size resulted in very wide confidence i n t e r v a l s .  64 Hence, no differences within treatments and only one between treatments were s i g n i f i c a n t at the 90% confidence l e v e l .  The f e r t i l i z e d p l o t tended to average  s l i g h t l y higher than the u n f e r t i l i z e d p l o t . Without f e r t i l i z a t i o n the subalpine native s o i l n i t r a t e dynamics were s i m i l a r to those of the montane native area (Figure 14).  F e r t i l i z a t i o n , however,  reduced the e a r l y summer loss of s o i l n i t r a t e and caused i t to increase sharply by October.  The early increase of s o i l n i t r a t e was also measured on the montane  reclaimed f e r t i l i z e d p l o t .  S o i l on the montane reclaimed and subalpine native  areas seemed d r i e r than the other two areas during root and s o i l sampling.  The  lower s o i l moisture may have lessened the amount of s o i l n i t r a t e l o s t by leaching 5.4.4  Subalpine Reclaimed Area This area showed the most dramatic e f f e c t s of f e r t i l i z a t i o n , r e s u l t i n g in  a more than 450% increase i n shoot N (Figure 11).  In contrast to the montane  reclaimed area the increase in shoot N a f t e r f e r t i l i z a t i o n was probably due to a more favorable moisture regime at the high-elevation s i t e which permitted rapid growth throughout the summer.  The higher N uptake was probably also influenced  by the lack of s o i l organic matter and, consequently,.by the lack of s i g n i f i c a n t microbial u t i l i z a t i o n of a v a i l a b l e N.  F e r t i l i z a t i o n of the subalpine reclaimed  area resulted i n the highest October 1977 shoot N l e v e l of any study area.  This  shoot N was to a large extent transferred to the d e t r i t u s compartment by f r o s t k i l l i n g soon a f t e r the sample was taken. The extremely low d e t r i t a l N masses i n t h i s area at the beginning of the study were due to the low shoot production on the s i t e in 1975. dynamics of t h i s area were unique among the study areas.  The d e t r i t a l N  Without f e r t i l i z a t i o n ,  d e t r i t a l N accumulated almost without i n t e r r u p t i o n (Figure 11).  This was due to  i n h i b i t e d d e t r i t a l decomposition which may have resulted from excessively wide C:N r a t i o s , lack of decomposers, low temperatures and a dry s o i l surface.  That  growth of the d e t r i t a l N pool exceeded that of the shoot N pool, even at the peak shoot growth period, suggests that s i g n i f i c a n t amounts of the system's a v a i l a b l e  65  N was being quickly converted into r e l a t i v e l y unavailable d e t r i t u s N.  Fertili-  zation caused a higher d e t r i t u s N peak in August which, subsequently, decomposed more quickly than d e t r i t u s on the u n f e r t i l i z e d p l o t .  However, by the end of the  study both plots had abo ut the same mass of N bound i n d e t r i t u s . 7  Subalpine reclaimed area root N l e v e l s were extremely low. tane reclaimed area had s u b s t a n t i a l l y larger root N masses.  Even the mon-  Nonetheless, the  subalpine reclaimed area root N pools grew s l i g h t l y even without f e r t i l i z a t i o n . F e r t i l i z a t i o n , however, caused a substantial increase in root N (Figure 12). S o i l t o t a l N l e v e l s were also extremely low on the subalpine reclaimed area.  Both plots had between 33 and 70 g m  of s o i l total N throughout the  study and were the poorest surface materials encountered in terms of t o t a l N (Figure 13).  Though to a much lesser extent than in the montane reclaimed area,  t o t a l s o i l N exceeded a r t i f i c i a l and possible N-fixation inputs. S o i l n i t r a t e on the subalpine reclaimed area underwent a nearly constant decline during the study.  F e r t i l i z a t i o n caused s o i l n i t r a t e l e v e l s to r i s e in  early summer and there was a very s l i g h t increase over winter on the u n f e r t i l i z e d plot (Figure 14).  The depletion of s o i l n i t r a t e suggests i n h i b i t i o n of N mineral-  i z a t i o n processes.  This, coupled with the extremely low t o t a l s o i l N l e v e l s ,  means that the subalpine reclaimed area w i l l continue to s u f f e r severe N def i c i e n c y i f maintenance f e r t i l i z a t i o n i s withheld. S o i l n i t r a t e also declined on the u n f e r t i l i z e d montane reclaimed p l o t . However, total s o i l N was high in t h i s area and legumes were abundant and r e producing.  Because a large pool of p o t e n t i a l l y a v a i l a b l e N e x i s t s on the montane  area in addition to a large N-fixation capacity adequate a v a i l a b l e N l e v e l s might be maintained. area.  No such p o s s i b i l i t y e x i s t s for the subalpine reclaimed  Inadequate decomposition i s the major deterrent to establishment of a  viable e x t r a - b i o t i c N-cycle.  Even with low l e v e l s of N in an ecosystem plant  p r o d u c t i v i t y can be maintained given adequate decomposer populations, near optimal s o i l moisture and temperature, a nutrient-conservative plant community which i s  66 capable of substantial i n - p l a n t c y c l i n g and s i g n i f i c a n t N - f i x a t i o n .  Apparently  few, i f any, of these conditions are met on the subalpine reclaimed area. 5.5 5.5.1  TEMPORAL DISTRIBUTION OF PHOSPHORUS Montane Native Grassland The pattern of shoot P f l u c t u a t i o n s generally resembled those of t o t a l  shoot mass and shoot N though concentration was much lower.  The doubling of  shoot P levels on the f e r t i l i z e d p l o t in mid-summer was not e n t i r e l y the r e s u l t of luxury consumption since through that period total shoot mass was also doubled. Thus, the P concentration remained f a i r l y constant in f e r t i l i z e d and u n f e r t i l i z e d plots (Figure 15). Detritus P tended to remain at high l e v e l s throughout the study on the u n f e r t i l i z e d p l o t . . The only periods of substantial decline were during the peak of the growing season (May to June) and from August to October 1977 (Figure 15). These periods of d e t r i t a l P loss coincided with maximum r a i n f a l l periods which apparently accelerated decomposition as well as leaching.  Since P in the plant  l a r g e l y occurs as highly mobile phosphates leaching could have accounted for a large proportion of P movement from the d e t r i t u s although the m o b i l i t y of phosphate would be severely r e s t r i c t e d soon a f t e r contact with the s o i l . The roots contained larger P reserves than e i t h e r shoots or d e t r i t u s .  Like  root N, root P tended to increase during periods of peak shoot growth i n d i c a t i n g that most of the system's P was drawn from the s o i l (Figure 16).  While over-  winter root P storage may be c r i t i c a l in i t s a v a i l a b i l i t y early in the spring; i t does not c o n s t i t u t e the bulk of the system's P throughout the growing F e r t i l i z a t i o n resulted in l i t t l e change in root P.  season.  Its e f f e c t was only apparent  in depressing the root P reserve by October. Available s o i l P l e v e l s on both f e r t i l i z e d and u n f e r t i l i z e d plots were _2 around 5.5 g m both at the beginning and end of the study period. Immediately -2 a f t e r f e r t i l i z a t i o n a v a i l a b l e P on both plots increased by nearly 5.0 g m . Since s i m i l a r increases occurred on both p l o t s , no e f f e c t of f e r t i l i z a t i o n on  67  montane r e c l a i m e d  shoot detritus  CN  I  S O N . D ^ F M A M J J A S O 1976 1977 f  k  fertilized  o  unfertilized  A S O N D J F M A M J J A S O 1976 1977  subalpine reclaimed  A . S 0 N D J F M A M J, . J A S 0 1976 1977 MONTH Figure  15. The temporal  'f  A S O N D J F M A M J ^ J A S O " 1976 1977  d i s t r i b u t i o n of P in chnnf-  i n d i c a t e s the date o f f e r t i 1 " z l t f o n ' .  t  ^+  anr  a  n  d  d e t r i t  ^>  the l e t t e r  68  native reclaimed A  fertilized  o  unfertilized Montane  Subalpine  3 2  1  Z  —• A S O N D J F M A M J - J A S O 1976 1977 MONTH  Figure 16.  cf ^  A S O N D J F M A ' M J J A S O 1976 1977  The temporal d i s t r i b u t i o n of root P, the l e t t e r ' f the date of f e r t i l i z a t i o n .  indicates  69 available s o i l P was apparent (Figure 17).  Also, as with the t o t a l s o i l N es-  timates poor precision made i n t e r p r e t a t i o n of the data d i f f i c u l t . 5.5.2  Montane Reclaimed Area Shoot P on t h i s area increased toward October in both years of the study.  This tendency made i t unique among study areas and was unlike shoot N on the montane reclaimed area (Figure 15).  The i n h i b i t i o n of mid-summer shoot P uptake  may have been caused by the drought.  Both f e r t i l i z e d and u n f e r t i l i z e d plots had  been f e r t i l i z e d in June 1976.  Since the u n f e r t i l i z e d p l o t in October 1977 was  the only p l o t which did not show t h i s response i t seems l i k e l y that t h i s June peak, August trough, October peak in shoot P was a r e g u l a r l y occurring combination of f e r t i l i z a t i o n and drought e f f e c t s . The reasons for the divergence of d e t r i t a l P values in October 1976 were unclear (Figure 15).  However, the f a l l of d e t r i t a l P on the u n f e r t i l i z e d p l o t  and i t s concurrent r i s e on the f e r t i l i z e d p l o t between May and June were s i m i l a r to the behavior of d e t r i t a l N a f t e r f e r t i l i z a t i o n . d e t r i t a l decomposition.  This was a period of rapid  While the u n f e r t i l i z e d p l o t l o s t t o t a l d e t r i t u s i t r e -  mained constant on the f e r t i l i z e d p l o t .  The increase in d e t r i t u s P concentration  on the f e r t i l i z e d p l o t was due to the accumulation of shoot P, d r o u g h t - k i l l i n g of the shoots and the transfer of shoot P to the d e t r i t u s compartment. The rate of d e t r i t u s P loss from May to June on the u n f e r t i l i z e d plot was almost 200% greater than net shoot P uptake.  While some of t h i s released P was  undoubtedly t i e d up i n insoluble form upon reaching the s o i l t h i s l i b e r a t e d det r i t a l P may have contributed s i g n i f i c a n t l y to plant P requirements during t h i s growth phase. Root P l e v e l s on both f e r t i l i z e d and u n f e r t i l i z e d plots remained s i m i l a r throughout the study.  However, l i k e root N l e v e l s , root P was lower a f t e r f e r t -  i l i z a t i o n on the f e r t i l i z e d p l o t than on the u n f e r t i l i z e d p l o t (Figure 16). This was due to the stimulation of shoot N and P uptake by f e r t i l i z a t i o n and i t s rapid transfer to d e t r i t u s by water s t r e s s .  The rapid loss of shoot P was, in  70  re c1aime d native A  fertilized  o  unfertilized  subalpine  montane  15  10  A S O N D J F M A M  1976  J J  A  S  O  A S O N D J F M A M J . J A S O  1977  1976  1977  MONTH  Figure 17.  The temporal d i s t r i b u t i o n of a v a i l a b l e s o i l P, the l e t t e r indicates the date of f e r t i l i z a t i o n .  ' f  71 part, replaced by diminishing root P reserves. Again, the confidence i n t e r v a l s for a v a i l a b l e s o i l P were wide.  However,  l e v e l s on the reclaimed plots c o n s i s t e n t l y averaged lower than those of corresponding sample periods on the native area (Figure 17).  Available s o i l P on the  f e r t i l i z e d p l o t did not reach i t s peak u n t i l August even though quick-release monoammoniurn phosphate was the P source in the f e r t i l i z e r mix.  The delay may  have been due to the dry s o i l conditions. 5.5.3  Subalpine Native Grassland Shoot P on t h i s area followed a pattern s i m i l a r to that of the montane  native area though P l e v e l s were consistently lower.  Shoot P uptake was much  more rapid on the montane native area between May and June while the subalpine area maintained higher shoot P l e v e l s into October 1977 (Figure  15).  In contrast to the montane native area, no increase in root P storage occurred in October on the subalpine native area.  Also, the u n f e r t i l i z e d p l o t  maintained nearly constant root P l e v e l s except in June and August.  The f e r t -  i l i z e d p l o t fluctuated more widely and by May had accumulated f a r more root P than the u n f e r t i l i z e d p l o t .  The f e r t i l i z e d p l o t also showed peak root P levels  in August rather than i n June but by October had a root P l e v e l s i m i l a r to that of the u n f e r t i l i z e d plot (Figure 16). Unlike the montane native area, f e r t i l i z a t i o n apparently increased a v a i l -2  able s o i l P on the subalpine native area. a l l of the added P.  The increase of 8 g m  accounted for  A v a i l a b l e s o i l P on the u n f e r t i l i z e d p l o t dropped somewhat  during the May to June period and rose again in August a f t e r d e t r i t u s and root had undergone large net P losses.  Despite a v a i l a b l e s o i l Ca l e v e l s as high as  any other area a v a i l a b l e s o i l P remained high on the subalpine plot (Figure 17). 5.5.4 Subalpine Reclaimed Area Shoot P, l i k e shoot N on the subalpine reclaimed p l o t increased r a p i d l y after f e r t i l i z a t i o n .  However, while the subalpine reclaimed f e r t i l i z e d p l o t ex-  ceeded a l l other areas i n p o s t - f e r t i l i z a t i o n shoot N increase i t was exceeded in  72 shoot P uptake by the montane native f e r t i l i z e d p l o t .  The subalpine reclaimed  area, however, maintained high shoot P levels longer than than any other p l o t . Shoot P l e v e l s on the subalpine reclaimed u n f e r t i l i z e d p l o t were s i m i l a r to those of the subalpine native u n f e r t i l i z e d p l o t throughout the study (Figure  15).  Detritus P on t h i s area accumulated slowly but s t e a d i l y on the u n f e r t i l i z e d p l o t while i t rose quickly and f e l l again on the f e r t i l i z e d p l o t to s l i g h t l y below that of the u n f e r t i l i z e d p l o t .  Relative to the other areas d e t r i t u s P on  the subalpine area was very low (Figure 15). While f e r t i l i z a t i o n resulted in an i n i t i a l depression of root P (perhaps due to high shoot demands) i t eventually rose to nearly 200% of root P on the u n f e r t i l i z e d p l o t (Figure 16).  This was the only area on which f e r t i l i z a t i o n  had a strong p o s i t i v e influence on root P l e v e l s .  Relative even to the montane  reclaimed area the subalpine reclaimed area had very low root P l e v e l s .  However,  without f e r t i l i z a t i o n root P did not decrease over the year. As in the other compartments a v a i l a b l e s o i l P on the subalpine reclaimed area was lower than on any other study area.  While a v a i l a b l e s o i l P rose in  summer on the f e r t i l i z e d p l o t the u n f e r t i l i z e d plot showedonly a very s l i g h t rise  in an otherwise downward trend (Figure 17).  This suggests that whatever  P i s made a v a i l a b l e by d e t r i t u s and root decomposition i s quickly t i e d up in unavailable form.  The very high levels of Ca on t h i s area imply that mineralized  phosphate would r a p i d l y bond with Ca to form immobile calcium phosphates. 5.6 5.6.1  TEMPORAL DISTRIBUTION OF POTASSIUM Montane Native Grassland F e r t i l i z a t i o n resulted in a substantial increase in shoot K uptake, nearly  doubling shoot K l e v e l s in June.  However, t h i s e f f e c t was s h o r t l i v e d with most  of the extra K l o s t by August and v i r t u a l l y none l e f t by October (Figure  18).  D e t r i t a l K on the f e r t i l i z e d p l o t started at 1.0 g m~* and remained near t h i s level throughout the study with only a s l i g h t dip in June and a slow decline -2 -2 from 1.0 g m to 0.6 g m between August and October 1977.  The u n f e r t i l i z e d  73  montane n a t i v e  montane r e c l a i m e d  A S O N D J F M A M J J A S O tn  1976  A S O N D J F M A M  1977  1976  1977  J J A S 0  C  •H CN  A S O N D J F M A M J J A S O 1976'  A S O N D J F M A M J J A S O  1977  1976  1977  f  MONTH Figure 18.  The temporal d i s t r i b u t i o n of K in shoots and d e t r i t u s , the l e t t e r ' f indicates the date of f e r t i l i z a t i o n .  74 p l o t d e t r i t a l K followed the same response except for a r i s e to 2.5 g m  in  October 1976 and an increase between August and October 1977 to previous October levels (Figure  18).  This constancy in d e t r i t u s K l e v e l s occurred despite wide f l u c t u a t i o n s in d e t r i t a l organic matter.  Apparently K i s leached almost immediately from the  newly-fallen d e t r i t u s leaving only very low resident l e v e l s , or i t was translocated to the roots very e f f i c i e n t l y during senescence. Higher l e v e l s of root K occurred on the u n f e r t i l i z e d p l o t than on the f e r t i l i z e d p l o t (Figure 19).  This was s u r p r i s i n g since i t occurred during a  period when net root production was higher on the f e r t i l i z e d p l o t .  The i n h i b i -  tion of root K accumulation on the f e r t i l i z e d p l o t may have been due to the highly stimulated shoot mass and i t s vigorous uptake of K. A v a i l a b l e s o i l K l e v e l s remained nearly constant (around 40 g m ) on the unfertilized plot.  A s l i g h t depression in K l e v e l s occurred between October and  May which was reversed as the growing season progressed.  F e r t i l i z a t i o n resulted  -2 -2 in an increase of 8.7 g m between May and June 1977 (8.3 g m of K were added). This l e v e l was maintained through August then dropped so that on f e r t i l i z e d and u n f e r t i l i z e d plots a v a i l a b l e s o i l K levels were s i m i l a r by the end of the study (Figure 20). 5.6.2  Montane Reclaimed Area The only apparent e f f e c t of f e r t i l i z a t i o n on the montane reclaimed area  was to increase October levels of shoot K (Figure 18).  This was of no great ad-  vantage to the plant community since f r o s t - k i l l i n g transferred most of t h i s shoot K to the d e t r i t u s compartment. Detritus K on the f e r t i l i z e d and u n f e r t i l i z e d p l o t s , l i k e those of the montane native area, varied very l i t t l e over the study period.  However, these  l e v e l s were somewhat lower than those of the native area and generally varied _2 between 0.4 and 0.7 g m .  In mid-summer the f e r t i l i z e d p l o t d e t r i t u s K rose  s l i g h t l y above that of the u n f e r t i l i z e d p l o t but f e l l back below that of the  75  native reclaimed A  fertilized  o  unfertilized  Figure 19.  The temporal d i s t r i b u t i o n of root K, the l e t t e r ' f the date of f e r t i l i z a t i o n .  indicates  76  r  reclaimed native  A  fertilized  o  unfertilized  montane  subalpine  70  I I I  60  •H  o  I .-A  50  (13  \ \ \  60  50  c 40  \  e 3  £1 ro  30  30  20  20  10.  10  \  /  40  \  \  V  r-l •H  > ro  0  AS  O N D J F M A M J 1976  Figure 20.  1977  f  J A S O  0  MONTH  A S O N D J F 1976  M A M J J A 1977  The temporal d i s t r i b u t i o n of a v a i l a b l e s o i l K, the l e t t e r indicates the date of f e r t i l i z a t i o n .  'f  SO  77 u n f e r t i l i z e d p l o t by October (Figure 18). Like root l e v e l s of N and P, root K peaked in June and declined toward winter (Figure 19).  Thus, while some translocation probably occurred, annual  root a t t r i t i o n was s u f f i c i e n t to s u b s t a n t i a l l y lower total root nutrient pools by spring.  Most of t h i s loss occurred in the f a l l .  F e r t i l i z a t i o n resulted in  no increase in root K, rather a s l i g h t decrease was noted in August and October 1977. -2 A v a i l a b l e s o i l K on both montane reclaimed plots averaged around 8.0 g m throughout the study.  Both plots showed a s l i g h t depression i n a v a i l a b l e s o i l  K during the maximum growth period then rose again by August.  However, on the  f e r t i l i z e d p l o t a much higher a v a i l a b l e s o i l K level was measured in August (Figure 20). P r i o r to 1977 roughly 6.6 g m reclamation began i n 1974.  of K had been added to these s o i l s since  Since l i t t l e more than t h i s was found on the montane  reclaimed area a r t i f i c i a l K inputs may have been c r i t i c a l in e s t a b l i s h i n g a large portion of the present a v a i l a b l e s o i l K pool.  However, the 8.9 g m r i s e on _2 the f e r t i l i z e d p l o t in August, nearly coinciding with the 8.3 g m K input, was -2 nearly a l l l o s t by October 1977.  Only 1.3 g m  of t h i s decline could be accounted  f o r by plant uptake, so i t seems l i k e l y that the s o i l a v a i l a b l e K level on t h i s area was l i m i t e d by the s o i l ' s cation exchange capacity.  Thus, additions beyond  the s o i l ' s capacity to adsorb exchangeable K would be leached away or perhaps f i x e d within expanding-clay l a t t i c e s . 5.6.3  Subalpine Native Grassland F e r t i l i z a t i o n caused a larger shoot K pool to be c a r r i e d into the f a l l .  The subalpine native p l o t absorbed much less of the added K into shoot matter than did the montane native p l o t (Figure 18). stress.  This may have been due to water  While s o i l moisture was not measured, s o i l cores taken in mid-summer  appeared much d r i e r on the subalpine p l o t .  This difference may have been due  to i t s position at the top of a ridge with l i t t l e downslope water flow and i t s  78 high wind and radiation exposure. Detritus K levels on both subalpine native plots behaved s i m i l a r l y to those on the montane areas.  They tended to remain near 1.0 g m  throughout  the study, the only difference was a small peak on the f e r t i l i z e d p l o t i n June 1977 (Figure 18). As in the montane native area, f e r t i l i z a t i o n of the subalpine native area depressed the accumulation of root K.  Unlike the montane native area, however,  t h i s e f f e c t was s h o r t l i v e d with both f e r t i l i z e d and u n f e r t i l i z e d plots reaching roughly  the same root K levels by August (Figure  19).  While a v a i l a b l e s o i l K was somewhat lower on the subalpine native area than on the montane native area i t was 3 to 4 times that found on the montane r e claimed area.  Also, a v a i l a b l e s o i l K on the subalpine native area tended to  follow seasonal growth patterns, r i s i n g during peak growth periods and f a l l i n g as the plant community entered dormancy.  F e r t i l i z a t i o n had no obvious e f f e c t  on a v a i l a b l e s o i l K (Figure 20). 5.6.4  Subalpine Reclaimed Area Like the montane reclaimed area a large loss of shoot K occurred between  October and May whereas the native areas gained s l i g h t l y in shoot K over this period (Figure 18).  However, the subalpine reclaimed u n f e r t i l i z e d p l o t had  roughly the same shoot K level in October 1977 as i t had in the preceding May. This indicates that the withholding of f e r t i l i z a t i o n mitigated the tendency of the reclaimed plant community to extend the growing season into l a t e f a l l .  Also,  peak shoot K l e v e l s on a l l u n f e r t i l i z e d p l o t s , native or reclaimed, were v i r t u a l l y the same i n d i c a t i n g that without f e r t i l i z a t i o n s u f f i c i e n t K was a v a i l a b l e to the reclaimed plant communities to maintain apparently adequate shoot K l e v e l s .  The  question of what constitutes "adequate" nutrient l e v e l s is d i f f i c u l t to assess. It i s used here with the assumption that the native grasslands are, f o r our purposes, stable and that they would not have persisted so long without "adequate" nutrient supplies.  (  79 Detritus K on both subalpine reclaimed plots rose from 0.1 to about 1.4 g m  between August and October 1976. _2  0.3 and 0.9 g m  These l e v e l s then f e l l o f f to between  f o r the remainder of the study.  No strong f l u c t u a t i o n s were  evident nor were there any differences due to f e r t i l i z a t i o n (Figure  18).  A f t e r the i n i t i a l r i s e in d e t r i t a l K i t soon assumed l e v e l s s i m i l a r to that of the other areas.  On a l l four areas, regardless of f e r t i l i z e r treatment,  d e t r i t u s K remained v i r t u a l l y unchanged averaging around 1.0 g m  throughout  the study. Root K on t h i s area increased s t e a d i l y throughout the study period ( F i g ure 19).  This was probably due to the youth of the root system and consequently  the absence of substantial annual a t t r i t i o n .  Unlike the montane reclaimed area  f e r t i l i z a t i o n of the subalpine reclaimed area resulted in an increase in root K. However, even the u n f e r t i l i z e d p l o t showed a substantial increase in root K during the study. A v a i l a b l e s o i l K, e x c e p t f o r a peak on the f e r t i l i z e d p l o t in May, remained -2 near 5.0 g m  on both plots throughout the study (Figure 20).  s i m i l a r to that of the montane reclaimed area. on the native areas fluctuated widely.  This pattern was  However, a v a i l a b l e s o i l K l e v e l s  This apparent buffering of reclaimed  s o i l K may be due to an equilibrium among unavailable, slowly a v a i l a b l e and a v a i l able forms of K.  This could occur in the presence of large amounts of 2:1 clays  which would f i x additional K between the clay l a t t i c e and remove i t from the a v a i l a b l e pool. 5.7  NITROGEN DYNAMICS The data presented in the preceeding figures were converted to the d i f f e r -  ences within compartments between successive sampling dates.  This permits an  estimate of the magnitude of n u t r i e n t gains and losses and i d e n t i f i e s the periods during which these changes occurred.  The data in the following tables represent  shoot N, d e t r i t u s N, root N and the sum of these which is c a l l e d total N. s o i l N i s also l i s t e d but i s not included in the " t o t a l " f i g u r e .  Total  80 5.7.1  Montane Areas F e r t i l i z a t i o n on the montane native area increased N f l u x through the  shoot compartment and increased the net accumulation of N in the root compartment.  The greater accumulation of d e t r i t u s N in the u n f e r t i l i z e d p l o t was due  to greater inputs between October and May so t h i s difference cannot be a t t r i b u t e d to f e r t i l i z a t i o n .  Between August and October 1977 the f e r t i l i z e d p l o t l o s t  -2  g m  8.1 -2  of shoot and d e t r i t u s N while the u n f e r t i l i z e d p l o t l o s t only 1.5 g m  from these compartments during this i n t e r v a l .  This suggests a higher rate of  decomposition on the f e r t i l i z e d p l o t , apparently commensurate with higher N i n puts, r e s u l t i n g in l i t t l e net change in d e t r i t a l N l e v e l s .  Thus, while f e r t -  i l i z a t i o n accelerated the rates of N exchange among compartments i t apparently, at l e a s t in the short term, did not r e s u l t in any serious depletion of the det r i t u s N pool or cause an overproduction of shoot at the expense of the root system.  Also f e r t i l i z a t i o n did not seriously a f f e c t the' timing of shoot N loss  in f a l l so l i t t l e shoot N was l e f t standing by October (Table 6). The u n f e r t i l i z e d montane reclaimed p l o t accumulated more plant and det r i t u s N over the year than the f e r t i l i z e d p l o t .  Table 6 shows that most of the  u n f e r t i l i z e d p l o t increase occurred in the root compartment and most of that occurred between May and June. During t h i s peak growth i n t e r v a l the f e r t i l i z e d p l o t accumulated much less root N. Had root N on the f e r t i l i z e d plot not increased _2  by 4 g m  between October and May (before f e r t i l i z a t i o n ) the difference in root  N gains of the two plots would have been even greater.  A large portion of the  net N accumulation on the f e r t i l i z e d p l o t occurred as a r e s u l t of shoot N i n creases between August and October 1977.  This l a t e season uptake was accompanied  by an accelerated root N loss and would probably be of minimal benefit to the plant community as i t came during a period of low temperatures which had already caused some f r o s t k i l l i n g by October. The u n f e r t i l i z e d p l o t showed net d e t r i t a l losses from May through October while the f e r t i l i z e d p l o t accumulated d e t r i t a l N from May to August and only l o s t  81 Table 6.  Net change i n N mass between sampling dates in the shoot, d e t r i t u s , root and s o i l compartments. The s o i l data r e present t o t a l N. The l e t t e r s ' F ' and 'NF' i n d i c a t e f e r t i l i z e d and u n f e r t i l i z e d plots r e s p e c t i v e l y .  NITROGEN MONTANE NATIVE F SHOOT DETRITUS AOG-OCT -3.3 0 -1 .94 OCT-MAY 5.77 0.72 MAY-JON 4.48 -4.60 JON-AUG -0.86 3. 38 -3.89 AOG-OCT -4.20 NET(OCT-•OCT) 0.45 MONTANE NATIVE NF AOG-OCT -4.28 OCT-MAY 0.93 MAY-JDN 1.71 JUN-AOG -1.22 AUG-OCT -1.09 NET (OCT-•OCT) 0.3 3  0.35  -6.29 12. 14 -8. 30 2.79 -0.44 6. 19  MONTANE RECLAIMED F AUG-OCT -0.74 -2.43 OCT-MAY 1.09 2.06 MAY-JUN 2. 71 1.29 -3.43 1.26 JUN-AOG AOG-OCT 1.73 -3.45 NET(OCT-•OCT) 2.10  1.16  MONTANE RECLAIMED NF AUG-OCT -3. 17 -2. 47 OCT-MAY 1.67 5.41 MAY-JUN 2. 15 -0.61 JON-AUG -2.58 - 1 . 14 ADG-OCT -0. 25 -1.76 NET(OCT-•OCT) 0.99  1. 90  (G M**-2) ROOT -15.09 -3.93 34.72 -13.32 -7.82  TOTAL -20.33 2.55 34.6 1 - 10.80 -15.90  SOIL 15.01 159.73 25. 18 -157.36 279.80  10.46  307.35  -18.23 5.14 23.66 -0.39 -20.40  684.01 -438.49 -187.46 7.59 273.06  1.48  8.01  -345.30  -4.14 4.39 1 .74 -0.05 -2.61  -7. 32 7.53 5.75 -2.23 -4.31  78.75 -40.77 -40.50 69.51 -98.27  3.47  6.7 4  -1 10.03  -0.87 2.73 5.18 -1.34 -1.93  -6.50 9.79 6.72 -5.05 -3.95  79.88 -153.94 123.51 24.6 3 -241.49  4.64  7.51  -247.29  9.65  -7.66 -7.93 30.25 -1 .97 -18.87  82 d e t r i t a l N from August to October.  This suggests sizeable shoot N inputs to  the d e t r i t u s compartment throughout the summer drought period and may account for the low root N gains on the f e r t i l i z e d p l o t .  The stimulation of shoot growth  due to f e r t i l i z a t i o n may have caused a continual drain on root N reserves which, soon a f t e r entering the shoot compartment, were transferred by water stress to the d e t r i t a l compartment.  Indeed, dead early season growth, p a r t i c u l a r l y of non-  drought-hardy species such as orchard grass and the true clovers, was abundant on the f e r t i l i z e d p l o t i n mid-summer. 5.7.2  Subalpine Areas F e r t i l i z a t i o n on the subalpine native area increased N inputs to the shoot  compartment though most of t h i s N was s t i l l not released to d e t r i t u s by the end of the study.  F e r t i l i z a t i o n accelerated the rates of d e t r i t a l loss though the  net yearly loss was less than on the u n f e r t i l i z e d p l o t due to a large d e t r i t u s N input over the winter.  F e r t i l i z a t i o n enhanced root N accumulation (Table 7).  F e r t i l i z a t i o n resulted in a 300% increase in plant and d e t r i t u s N accumul a t i o n on the subalpine reclaimed area.  Much of the gain in the f e r t i l i z e d p l o t  was in the shoot compartment which maintained a large N pool into October.  How-  ever, f e r t i l i z a t i o n also resulted in a nearly doubled root N accumulation.  Both  plots accumulated d e t r i t a l N.  From October 1976 to October 1977 the f e r t i l i z e d  -2 -2 p l o t gained 1.7 g m of d e t r i t u s N while the u n f e r t i l i z e d p l o t gained 1.2 g m of d e t r i t u s N.  The annual turnover of d e t r i t u s N on the u n f e r t i l i z e d p l o t was  lower than on any other study area.  Only between June and August was there a  net loss of d e t r i t u s N on t h i s p l o t .  Detritus N buildup on t h i s u n f e r t i l i z e d  p l o t was not large r e l a t i v e to those on some of the other study p l o t s , but the low N levels in shoots and roots on this p l o t suggest that d e t r i t u s N accumulation and i t s low rate of release may prove a s i g n i f i c a n t loss of a v a i l a b l e N in the future (Table 7). 5.8 5.8.1  PHOSPHORUS DYNAMICS Montane Areas  83  Table 7.  Net change in N mass between sampling dates i n the shoot, d e t r i t u s , root and s o i l compartments. The s o i l data represent total N. The l e t t e r s F ' and 'NF' indicate f e r t i l i z e d and u n f e r t i l i z e d plots respectively. !  SUBALPINE AUG-OCT CCT-MAT MAY-JUN JUN-AUG AUG-OCT N E T ( O C T - OCT)  SUBALPINE AUG-OCT OCT-MAY HAY-JUN JUN-AUG AUG-OCT  NATIVE SHOOT -1.90 0.77 3.02 -0. 37 -0.84  NITROGEN F DETRITUS -3.04 6.99 -3.57  2.58  N A T I V E NF -1.45 0.81 1.03 -1.11 -1. 05  - 2 . 29 -1.50 -0.37  -4.92 - 1 . 12 0.41 2.88 - 3 . 37  N E T ( O C T - •OCT) - 0 . 3 2  - 1 . 20  SUBALPINE AUG-OCT OCT-MAY MAY-JUN JUN-AUG AUG-OCT  F -0.41  N E T ( O C T - OCT)  SUBALPINE AUG-OCT OCT-MAY MAY-JUN JUN-AUG AUG-OCT  RECLAIMED -2.37 -0.48 6. 1 4 2. 3 8 -4. 14 3.90  RF.CL A I M E D -1.56 -0. 29 1.34 -0.80 -0.37  N E T ( O C T - •OCT) - 0 . 1 2  (G  M**-2) ROOT -14.11 45. 13 1 .02 -2.13 -31.65 12.37  -13.00 14.92 2 7 . 10 -14.06 -20.75 7.21  TOTAL -19.0 5 52.88 0.48 -4.78 -34.00 14.58  -19.36 14.60 . 28.55 - 12.29 -25.17  SOIL -219.46 1 9 8 . 17 . -48.23 -280.40 182.67 52.21  -121.5 8 -22.01 -49.3 6 -101.46 1 5 7 . 19  5.69  -15.64  -2.86 3.0 9 7.90 4.3 9 -6.44  18.29 -10.46 -8.02 -4.07  2.22 0.35 0.63 -1.50  -0.06 1.34 1.41 1.37 -0.80  1.70  3.32  8.94  -25.27  -1.42 1. 3 4 2.54  -0.6 2 0.0 3  -0.16 0.60 0.48 1 .00 -0.47  21 .56 -15.09 - 9 . 42 -12.33 9 .00  1.16  1.61  2.65  -2 . 7 2  NF 0. 3 0 1. 0 4 0.71  -0.43 -0.80  -27.84  84 While the montane native plots both l o s t plant and d e t r i t a l P throughout the study, the loss was twice as high on the f e r t i l i z e d p l o t .  Most of t h i s ad-  d i t i o n a l loss occurred in the d e t r i t u s and root compartments.  While net root P  increases between May and June were s i m i l a r on the two p l o t s , f e r t i l i z a t i o n accelerated root P loss between August and October.  F e r t i l i z a t i o n also resulted  in a nearly 200% increase in shoot P uptake between May and June.  However, the  rate of decline was commensurate so that the f e r t i l i z e d p l o t simply underwent a larger P f l u x though the shoot compartment (Table 8). On the montane reclaimed f e r t i l i z e d p l o t plant and d e t r i t u s compartments gained 0.1 g m  of P from October 1976 to October 1977.  u n f e r t i l i z e d p l o t l o s t 0.3 g m  During t h i s period the  of P from the same compartments.  However, i n -  spection of i n d i v i d u a l compartments (Table 8) revealed that the u n f e r t i l i z e d plot gained more root P while i t l o s t more d e t r i t u s P and p a r t i c u l a r l y shoot P. The loss of shoot P indicates that the u n f e r t i l i z e d p l o t shoot system entered f a l l dormancy more r a p i d l y than did that of the f e r t i l i z e d p l o t .  The periods of  root P increase on the u n f e r t i l i z e d p l o t were May to June and June to August with the greatest increase occurring between June and August.  The f e r t i l i z e d p l o t ,  however, gained root P between October and May (before f e r t i l i z a t i o n ) , l o s t a s l i g h t amount of root P between May and June then gained 40% less root P than did the u n f e r t i l i z e d p l o t between June and August.  The shoot uptake and loss  pattern was s i m i l a r to that of nitrogen in t h i s area.  Shoot P uptake was v i r -  t u a l l y the same on both plots between May and June and both plots l o s t the same amount of shoot P between June and August.  Then, as shoot P on the u n f e r t i l i z e d  p l o t remained constant through October the f e r t i l i z e d p l o t gained 0.3 g m shoot P.  of  Also, between May and June d e t r i t u s P increased strongly on the f e r t -  i l i z e d p l o t while the u n f e r t i l i z e d p l o t l o s t equally as much d e t r i t u s P.  On the  f e r t i l i z e d p l o t coincidence of root P l o s s , a net gain in shoot P s i m i l a r to that of the u n f e r t i l i z e d p l o t and a large increase in f e r t i l i z e d p l o t d e t r i t a l P suggest that f e r t i l i z a t i o n caused a stimulation of shoot growth at the expense of  85 Table 8.  Net change i n P mass between sampling dates in the shoot, d e t r i t u s , root and s o i l compartments. The s o i l data r e present a v a i l a b l e P. The l e t t e r s ' F ' and 'NF' i n d i c a t e f e r t i l i z e d and u n f e r t i l i z e d plots r e s p e c t i v e l y .  PHOSPHORUS MONTANE NATIVE F SHOOT DETRITUS AOG-OCT -0.32 0.39 OCT-MAY -0. 1 1 -0. 43 MAY-JON 0.82 -0.22 JON-AUG -0.39 0. 47 AUG-OCT -0.44 -0.59  (G M**-2) ROOT 1.41 -2.12 2.34 -0.09 -1.55  TOTAL 1.48 -2.66 2.9 3 0.0 -2.58  SOIL 1 . 27 2.91 5. 34 -3.06 -6.09  NET (OCT- OCT) -0. 12  -0.77  -1.42  -2.31  -0. 90  HONTANE NATIVE NF AUG-OCT -0.61 GCT-MAY -0.01 MAY-JUN 0.34 JUN-AUG -0. 14 AUG-OCT -0.23  0.48 -0.02 -0.62 0.76 -0.23  1 .60 -2.17 2 .36 -0.26 -0.88  1.49 -2.21 2.07 0.37 -1.34  2. 13 -2.48 4. 20 -4.12 -0.04  NET (OCT- OCT) -0.04  -0. 1 1  -0.95  -1.11  -2.44  -0.29 0.23 -0.01 0.44 -0.51  -0.-14 0.10 0.67 -0.04 -0.64  1.39 -0.71 1. 33 2.47 -2.71  0.15  0.09  • 0.38  0.09 -0.07 0.26 0.73 -0.65  0.71 -0.10 -0.09 0.35 -0.44  1. 29 0.84 -2.09 0.23 0.37  0.27  -0.28  -0.65  MONTANE RECLAIMED F AUG-OCT 0.24 -0.09 OCT-MAY -0.26 0.13 MAY-JUN 0.22 0.47 JUN-AUG -0.33 -0.15 AUG-OCT 0.32 -0.46 NET (OCT-•OCT) -0.05  -0.01  MONTANE RE CLAIMED NF AUG-OCT 0.22 0.41 OCT-MAY -0.3 3 0. 29 MAY-JUN 0.21 -0.57 JUN-AUG -0.30 -0.07 AUG-OCT 0.04 0.17 NET (OCT- OCT) -0.38  -0. 18  86 root P reserves and that the added growth was under environmental control (water stress) which l i m i t e d net gains so that the additional shoot P was r a p i d l y transferred to the d e t r i t u s compartment. Very l i t t l e of the added P was apparent as a v a i l a b l e s o i l P. of the montane native area increased s o i l P by only 1.1 g m  Fertilization  . Fertilization  of the montane reclaimed area, however, increased a v a i l a b l e s o i l P by 3.8 g m . The r e s u l t i n g increase in a v a i l a b l e s o i l P peaked in August when plant uptake was minimal.  As very l i t t l e of t h i s added s o i l P was taken up by plants the _2  loss of 2.7 g m  of a v a i l a b l e s o i l P between August and October was probably  due to phosphate immobilization by Ca. 5.8.2  Subalpine Areas The net accumulation of P i n the subalpine native plant and d e t r i t u s com-  _2 partments between October 1976 and October 1977 was 1.0 g m on the f e r t i l i z e d -2 plot while the u n f e r t i l i z e d p l o t underwent a net loss of 0.7 g m compartments over the year.  in these  Most of the P increase on the f e r t i l i z e d p l o t was  in the root system p r i o r to f e r t i l i z a t i o n so the e f f e c t of f e r t i l i z a t i o n on root P uptake i s unclear.  F e r t i l i z a t i o n accelerated the rate of d e t r i t a l P l o s s .  This  was in part due to the longer retention time of shoot P in the f e r t i l i z e d p l o t for much of i t s P was not added to the d e t r i t u s compartment u n t i l a f t e r the study was completed (Table 9). Most the plant and d e t r i t u s P on the f e r t i l i z e d p l o t accumulated p r i o r to f e r t i l i z a t i o n .  This p r e f e r t i l i z a t i o n increase of 4.2 g m  was l a r g e l y in  -2 the root compartment. A f t e r the addition of 6.9 g m of f e r t i l i z e r P a v a i l a b l e -2 -2 s o i l P rose by 8.0 g m . However, plant P uptake was only 0.7 g m between May and June.  Between June and August a v a i l a b l e s o i l P f e l l at over three times  the rate of root P uptake.  Between June and October, when plant P uptake was  -2 -2 only 0.8 g m , a v a i l a b l e s o i l P f e l l by 4.9 g m .  Most of t h i s was probably  l o s t to the formation of nearly insoluble calcium phosphates.  87  Table 9.  Net change in P mass between sampling dates in the shoot, d e t r i t u s , root and s o i l compartments. The s o i l data r e present a v a i l a b l e P. The l e t t e r s ' F ' and 'NF' i n d i c a t e f e r t i l i z e d and u n f e r t i l i z e d plots r e s p e c t i v e l y .  PHOSPHORUS SD BALPINE NATIVE F SHOOT DETRITUS AUG-OCT -0. 26 0.21 OCT-MAY 0.05 0.06 MAY-JUN 0. 43 0.01 JUN-AUG -0.07 -0.28 AUG-OCT -0. 15 -0.30 NET (OCT-OCT) 0. 26 SUBALPINE NATIVE AUG-OCT -0. 1 4 OCT-MAY 0.01 MAY-JUN 0.26 JUN-AUG -0.21 AUG-OCT -0.22 NET(OCT-•OCT) -0. 16 SUBALPINE AUG-OCT OCT-MAY MAY-JUN JUN-AUG AUG-OCT  TCTAL -0.96 4.23 0.71 0.45 -4. 38  SOIL -1 . 19 1. 17 8.03 -2.78 -1.86  1.27  1.01  4.56  0. 08 -0. 62 0. 02 0. 29 -0. 35  0.02 0.43 2.52 -1.36 -1 .49  -0.04 -0.1 8 2.8 0 -1.28 -2.06  0.26 0.49 -0. 67 1.39 -3.04  -0. 66  0. 10  -0.72  -1 .83  -0.01 0.16 -0.03 0.76 -0.03  -0.36 0.23 0.79 0.92 -0.33  -0.82 0.03 1. 15 0.28 -1.51  0.86  1.61  NF  0. 08  SUBALPINE RECLAIMED NF AUG-OCT -0.33 0. 11 OCT-MAY -0. 11 0. 02 MAY-JUN 0.26 0. 1 1 JUN-AUG -0. 17 -0. 05 AUG-OCT -0.08 -0. 01 NET(OCT- OCT) -0. 10  ROOT -0.92 4.13 0.27 0.80 -3.93  -0.51  RECLAIMED F -0.40 0. 06 -0.06 0. 1 1 0.6 0 0. 22 0. 15 0. 02 -0.03 -0. 27  NIT(OCT-•OCT) 0.66  (G M**-2)  0. 07  -0.05  -0.22 -0.10 0.23 0.08 -0.21  -0.44 -0.19, 0.60 -0.15 -0.29  -0. 30 -0.65 0.41 0.01 -0. 46  0.0  -0.03  -0.69  88 -2 F e r t i l i z a t i o n of the subalpine reclaimed area resulted in a 1.6 g m i n crease in plant and d e t r i t u s P over the year. _2 roots though 0.7 g m  Most of the increase was in the  of the increase remained in the l i v e shoot mass.  The  u n f e r t i l i z e d p l o t l o s t a very s l i g h t amount of plant and d e t r i t u s P (0.03 g m ) with root P l e v e l s remaining unchanged between October 1976 and October 1977. There was a s l i g h t decrease in shoot P l e v e l s r e f l e c t i n g e a r l i e r entry into f a l l dormancy in the u n f e r t i l i z e d p l o t .  Detritus P increased by the same small  amount on both plots (Table 9). Root P on the f e r t i l i z e d p l o t was depleted during the period of maximum shoot growth but increased between June and August.  The major net increases in  root P on the u n f e r t i l i z e d p l o t occurred between May and June in a pattern s i m i l a r to those of the u n f e r t i l i z e d native p l o t s . crease in shoot P.  However, p o s t - f e r t i l i z a t i o n plant net uptake was only 1.5  -2 g m reflecting inefficient P utilization. _2 1.0 g m  F e r t i l i z a t i o n t r i p l e d the net i n -  after f e r t i l i z a t i o n .  Even a v a i l a b l e s o i l P increased only  Between August and October a l l compartments on  both plots l o s t P. The i n e f f i c i e n c y of P f e r t i l i z a t i o n was evident on a l l of the areas and may be unavoidable as methods which could increase e f f i c i e n c y ( i . e . f e r t i l i z e r banding) would be impractical in the rocky, often steep overburden. 5.9  POTASSIUM DYNAMICS  5.9.1. Montane Areas F e r t i l i z a t i o n decreased plant and d e t r i t u s K l e v e l s on the montane native area, while on the u n f e r t i l i z e d plot plant and d e t r i t u s K increased.  Root K net  gains and losses were s i m i l a r throughout the year on both plots except between May and June where the u n f e r t i l i z e d p l o t gained 38% more root K than the f e r t i l i z e d plot.  This was also a period when shoot K increased r a p i d l y and was 59%  greater on the f e r t i l i z e d plot (Table 10).  The stimulation of shoot growth and  K uptake may have been responsible for the lower accumulation of K in the roots. Available s o i l K levels rose a f t e r f e r t i l i z a t i o n but less than the 9.0 g m"'  89  Table 10.  Net change in K mass between sampling dates in the shoot, d e t r i t u s , root and s o i l compartments. The s o i l data r e present a v a i l a b l e K. The l e t t e r s ' F ' and 'NF' indicate f e r t i l i z e d and u n f e r t i l i z e d plots r e s p e c t i v e l y .  MONTANE AOG-OCT OCT-MAY MAY-JON JUN-AUG AOG-OCT  POTASSIUM NATIVE F SHOOT DETRITUS -U.32 0 . 16 0.47 - 0 . 18 6.4 9 -0.23 -3.90 0.18 -2.67 -o. a 1  NET(OCT-OCT)  MONTANE AOG-OCT OCT-MAY MAY-JON JUN-AOG AUG-OCT  0.89 -1.02 - 0 . 57 0.63 0 . 24  0.44  RECLAIMED 0.61 -1 . 3 5 2. 37 - 2 . 72 1.83  NET(OCT-OCT)  MONTANE AUG-OCT CCT-MAY MAY-JUN JUN-AUG AUG-OCT  -0.64  N A T I V E NF - a , 99 0.58 2.66 - 1 . 03 -1.7.7  NET(OCT-OCT)  MONTANE AUG-OCT OCT-MAY MAY-JUN JUN-AUG AUG-OCT  0.39  -0.72  NET(OCT-OCT) - 1 . 2 7  M**-2) ROOT -0.32 -0.30 2.47 -0.63 -1.52  TOTAL -4,48 0.0 8.72 -4.35 -4.60  0.02  - 0 . 23  -0.56 -0.40 3.98 -0.58 -1 . 7 4 1 .26  -4.65 -0.85 6.07 -0.98 -3.28 0.9 6  SOIL 1.66 10.71 15.43 -0.60 - 16.80 8.74  3.62 -8.77 1 .77 9. 87 6.48 9.35  F 0.03 -0.31 0.35 -0.16 - 0 . 10  0.13  RECLAIMED 0.48 -1.14 2.00 -2.68 0.55  (G  -0.22  -0.85 0.61 1.25 -1.00 -0.44  -0.19 -1.06 3.97 -3.88 1 .29  -1.95 4.94 -0.51 8.91 -10.91  0.42  0.32  0.77 -0.68 - 0 . 14 0.10 -0.06  -0.35 0.18 1.60 -0.74 -0.44  C.89 -1.63 3.46 -3.32 0.04  0.87 1.11 -2.85 3. 65 - 4 . 37  - 0 . 78  0.60  -1.45  -2.46  2.43  NF  90 _2 r i s e i n plant K l e v e l s which alone would more than account f o r the 8.3 g m a r t i f i c i a l K input.  Nonetheless, leaching and perhaps K - f i x a t i o n in expanding  l a t t i c e clays brought a v a i l a b l e s o i l K to nearly the same l e v e l s by October 1977 in f e r t i l i z e d and u n f e r t i l i z e d p l o t s . F e r t i l i z a t i o n of the montane reclaimed area increased plant and d e t r i t u s _2 K by 0.3 g m between October 1976 and October 1977 while the u n f e r t i l i z e d p l o t _2 l o s t 1.4 g m  over this period (Table 10).  However, most of t h i s difference  was in shoot K i n d i c a t i n g , as with P, the e a r l i e r entry into f a l l dormancy on the u n f e r t i l i z e d p l o t .  The u n f e r t i l i z e d p l o t gained more root K over the year.  While shoot K gains were s l i g h t l y higher on the f e r t i l i z e d p l o t , root K increased at a lower rate than on the u n f e r t i l i z e d p l o t .  This, combined with the r i s e in  d e t r i t a l K between May and June suggests, again, stimulation of shoot K uptake at the expense of root K and i t s rapid transfer to the d e t r i t a l K pool.  As sug-  gested f o r N and P, water stress probably l i m i t e d the amount of shoot that could be supported at any given time.  Thus, new shoot additions resulted in comensur-  ate additions to the d e t r i t u s compartment. Available s o i l K on the f e r t i l i z e d p l o t increased r a p i d l y between June and August. By then v i r t u a l l y a l l of the plant and d e t r i t u s K that had accumulated -2 -2 between May and June (4.0 g m ) had been l o s t again, releasing 3.9 g m of K to the s o i l .  Additional. K was perhaps released from undissolved KC1 grains that  had not entered solution by the June sample. surface was p a r t i c u l a r l y dry on t h i s s i t e .  This was a dry period and the s o i l Indeed, some of the pink muriate of  potash granules were observed on the surface, two weeks a f t e r a p p l i c a t i o n , during the June sampling.  K losses from plant and d e t r i t u s compartments on the unfert-  i 1 i z e d p l o t between June and August were 3.3 g m-2 and corresponded to a 3.6 g m -2 increase in a v a i l a b l e s o i l K over the same period.  However, a l l of t h i s s o i l K  increase was l o s t between August and October suggesting e i t h e r leaching or f i x a tion of the additional K in expanding-!attice c l a y s .  91 5.9.2  Subalpine Areas F e r t i l i z a t i o n on the subalpine native area resulted in a large net i n -  crease of plant and d e t r i t u s K (Table 11).  As on the other areas, however, most  of this increase was in the shoot compartment r e f l e c t i n g the delay in f a l l mancy caused by f e r t i l i z a t i o n .  dor-  A l s o , as noted on the montane areas, f e r t i l i z a t i o n  resulted i n a smaller increase in root K levels than on the control p l o t .  Fert-  i l i z a t i o n increased d e t r i t a l K between May and June while the u n f e r t i l i z e d p l o t l o s t d e t r i t a l K over the same period. l a t i o n of root K.  F e r t i l i z a t i o n also i n h i b i t e d the accumu-  So f e r t i l i z a t i o n again stimulated shoot growth so that the  r o o t - s o i l system could not supply s u f f i c i e n t water or K.  The r e s u l t was s i m i l a r  to that of the montane reclaimed area where the net shoot increase was s i m i l a r on both f e r t i l i z e d and u n f e r t i l i z e d plots while f e r t i l i z a t i o n increased d e t r i t u s K and depressed the accumulation of root K. Available s o i l K increased r a p i d l y between October and May on the f e r t i l i z e d p l o t and between May and June on the u n f e r t i l i z e d p l o t . was apparent for a v a i l a b l e s o i l P.  The same pattern  This may explain the e a r l i e r i n i t i a t i o n of  rapid growth on the f e r t i l i z e d p l o t and may have been due to a s l i g h t difference in s o i l moisture, snow d r i f t i n g or aspect. F e r t i l i z a t i o n of the subalpine reclaimed area resulted in a large net i n crease of plant and d e t r i t u s K between October 1976 and October 1977.  While  nearly a l l of t h i s increase was in the shoot compartment, root K increased at a greater rate than on the u n f e r t i l i z e d p l o t (Table 11).  This was the only study  area where f e r t i l i z a t i o n did not depress the net increased in root K over the year. 6.0  DISCUSSION  6.1  EFFECTS OF FERTILIZATION In a l l study plots f e r t i l i z e r addition resulted in increased shoot pro-  duction.  This increase was most pronounced on the subalpine reclaimed area.  On  the montane reclaimed area the increased shoot production due to f e r t i l i z a t i o n was  92 Table 11. Net change i n K mass between sampling dates in the shoot, d e t r i t u s , root and s o i l compartments. The s o i l data r e present a v a i l a b l e K. The l e t t e r s ' F ' and 'NF' i n d i c a t e f e r t i l i z e d and u n f e r t i l i z e d plots r e s p e c t i v e l y .  SUBALPINE AUG-OCT GCT-HAY MAY-JUN JUN-AUG AUG-OCT NET(OCT-OCT) SUBALPINE AUG-OCT OCT-MAY MAY-JUN JUN-AUG AUG-OCT  POTASSIUM NATIVE F SHOOT DETRITUS -1.39 0. 30 0.56 -0.22 1.67 0. 86 -0. 19 -0.98 -1.10 -0.14 0.94  NET(GCT-OCT) SUBALPINE AUG-OCT CCT-MAY MAY-JUN JUN-AUG AUG-OCT  ROOT -0.38 2.44 0.83 . -0.61 -2.30  TOTAL -1.48 2.79 3.36 -1.77 -3.55  SOIL -12.86 11.68 7.27 5.22 -16.25 7.92  -0.48  0.36  0.33  NATIVE NF -1.34 0.02 0.52 -0.14 1.97 -0.51 -1.59 0.42 -1.39 -0.29  -0.75 1.37 2.88 -2.07 -1.55  -2.07 1 .74 4.35 -3.24 -3.24  -3. 89 7.82 11.72 4.31 -26.58  -0.52  0.63  -0.39  -2.73  RECLAIMED F -1.81 1.55 -2.13 -1.39 5.26 0.58 5.36 0.07 -3.66 -0.15  0.11 0.09 0.82 -0.49 0.19  -0. 16 -3.42 6.67 4.94 -3.6 3  -1.52 8.23 -4.85 -0.72 -2. 10  0.61  4.56  0.56  NET(OCT-OCT)-0.49 SUBALPINE AUG-OCT CCT-HAY MAY-JUN JUN-AUG AUG-OCT  (G M**-2)  4.83  -0.89  RECLAIMED NF -0.97 1.11 -1.42 -0.71 2.63 0.25 -1.35 -0.33 -0.92 0.21  NET(OCT-OCT)-1.06  -0.58  0.05 0.04 0.49 0.14 • -0.31 0.36  0.20 -2.10 3.37 -1.54 -1.0 1  -0. 72 0.60 0.29 0.25 -1.59  -1.28  -0.45  93 not apparent u n t i l October because shoot masses on both f e r t i l i z e d and u n f e r t i l i z e d plots were equally depressed by the mid-summer drought. Larger shoot standing crops were also maintained into October on the f e r t i l i z e d plots.  This e f f e c t was apparent on both native and reclaimed areas  i n d i c a t i n g that the tendency of reclaimed areas to remain green very l a t e in the year was mainly due to maintenance f e r t i l i z a t i o n and only to a lesser extent the r e s u l t of poor adaptation of the agronomic species.  Evidence f o r some genetic  component in f a l l dormancy l i e s in the somewhat greater shoot masses l e f t in the u n f e r t i l i z e d reclaimed plots in October 1977 as opposed to the native p l o t s . Also, f e r t i l i z a t i o n delayed flowering on the subalpine reclaimed area where no mature seed could be found by mid-September 1977. F e r t i l i z a t i o n stimulated shoot production to a greater degree than root production.  This resulted in a narrowing of root:shoot r a t i o s even on native  areas though the e f f e c t was most pronounced on the subalpine reclaimed area. Also, while net root production was stimulated by f e r t i l i z a t i o n on the subalpine reclaimed area, f e r t i l i z a t i o n resulted in diminished gains in root mass, root N, root P and root K on the montane reclaimed area. The explanation l i e s in the e f f e c t s of drought at the montane area where no s i g n i f i c a n t p r e c i p i t a t i o n f e l l between the second week of June and the f i r s t week of August 1977. temperatures.  This was also a period of clear skies and high daytime  By the f i r s t week of August several species on the montane r e -  claimed area had died to the ground. clovers.  Those included orchard grass and the true  Red fescue was also damaged by drought while the wheatgrass, smooth  brome and a l f a l f a showed no adverse e f f e c t s .  Since t h i s study was conducted at  the community level the responses of a l l plant species within a given p l o t were integrated.  F e r t i l i z a t i o n of the montane reclaimed area resulted in increased  shoot production, decreased root production and increased inputs i n t o d e t r i t u s as compared to the u n f e r t i l i z e d montane reclaimed p l o t .  That shoot standing  crop on both plots were s i m i l a r u n t i l early f a l l suggests factors other than  94 nutrient a v a i l a b i l i t y l i m i t e d the mass of shoot that could be supported through the summer.  Water stress seems the most l i k e l y explanation as many species had  died back to the ground by e a r l y August.  Since an e f f e c t of water stress i s to  l i m i t d i f f u s i o n and mass flow of nutrients from the s o i l to the roots, increased a c t i v i t y of nutrient ions due to f e r t i l i z a t i o n could p a r t i a l l y o f f s e t t h i s e f f e c t and allow continued production while the d e f i c i t between water uptake and t r a n s p i r a t i o n would be aggravated.  This would, under s u f f i c i e n t l y severe conditions,  r e s u l t in shoot death. No drought e f f e c t s were apparent on the subalpine reclaimed area.  This  could have been due to greater s o i l moisture storage from the greater winter snowpack as well as lower temperatures throughout the summer.  The native areas,  as w e l l , showed l i t t l e effect.due to the mid-summer drought. In cold regions the d e t r i t u s pool often acts as a "sink" for n u t r i e n t s . This i s the r e s u l t of i n h i b i t e d decomposition and has been a major problem in high elevation and high l a t i t u d e reclamation.  For t h i s reason d e t r i t a l  dynamics,  p a r t i c u l a r l y on the subalpine reclaimed area, were important in assessing n u t r i e n t s t a b i l i t y in the study. F e r t i l i z a t i o n increased the rate of d e t r i t u s decomposition.  However, i t  also tended to increase both shoot production and d e t r i t a l nutrient q u a l i t y . Consequently, in most cases d e t r i t a l organic matter l e v e l s f e l l while d e t r i t a l N and P levels rose on f e r t i l i z e d p l o t s .  F e r t i l i z a t i o n narrowed the n u t r i e n t :  carbohydrate r a t i o s of d e t r i t u s , thus accelerating decomposition.  On u n f e r t i l i z e d  plots d e t r i t a l organic matter e i t h e r increased dramatically (subalpine reclaimed) or decreased at a slower rate than on the f e r t i l i z e d p l o t (subalpine n a t i v e ) . The aberrant behavior of the montane reclaimed area i s a t t r i b u t e d to the stimul a t i o n of shoot and d e t r i t u s production during the drought period at the expense of the root system.  For example, between May and June 1977, the period of peak  shoot and root production as well as d e t r i t u s decomposition, the f e r t i l i z e d p l o t gained only h a l f as much root mass as the u n f e r t i l i z e d p l o t .  During the same  95 period the u n f e r t i l i z e d plot l o s t 128 g m plot gained 4 g m .  of d e t r i t u s while the f e r t i l i z e d  Also, during t h i s period net shoot standing crops were  nearly i d e n t i c a l on both p l o t s . The accelerated d e t r i t a l decomposition on the native areas could have profound e f f e c t s i f a long-term program of heavy f e r t i l i z a t i o n was employed to o f f set losses in ungulate range due to mining.  Effects would probably include  accelerated n u t r i e n t c y c l i n g with attendant losses in surface d e t r i t u s .  Also,  i t i s l i k e l y that plant community composition would change to the detriment of legumes in p a r t i c u l a r .  On the p o s i t i v e side, such a program would increase both  shoot and root p r o d u c t i v i t y and the carrying capacity of the range.  A l s o , in a  r e a l i s t i c native range f e r t i l i z a t i o n program much lower rates of f e r t i l i z a t i o n would be used. at most.  A l s o , f e r t i l i z a t i o n would l i k e l y occur at 2-3 year i n t e r v a l s  This would minimize the chances of adverse changes while assuring i n -  creased p r o d u c t i v i t y . On the subalpine reclaimed area d e t r i t a l accumulation over the year exceeded net shoot production on the u n f e r t i l i z e d p l o t .  On the adjacent f e r t i l i z e d  plant, however, d e t r i t u s l e v e l s dropped s l i g h t l y over the year. Detritus behaves as a mulch and moderates the s o i l thermal and moisture environment by reducing incident r a d i a t i o n and wind.  Brink e_t al_. (1967) i n -  dicated the problems in plant establishment posed by needle-ice on bare, high elevation s o i l s .  S o i l coverage by l i v e or dead vegetation mitigates t h i s hazard.  However, in cold regions excessive d e t r i t a l buildup can have adverse e f f e c t s as well.  For example, i n s u l a t i o n of the s o i l from the a i r can aggravate f r o s t i n -  jury to plants (Geiger, 1965). ductivity.  This r e s u l t s from i n h i b i t e d upward thermal con-  On c l e a r , cool and calm nights, when convection i s low and r a d i a t i o n  losses to the sky are r a p i d , the r e s t r i c t e d conduction of heat from the s o i l (and the s o i l ' s r e s t r i c t e d a b i l i t y to absorb heat during the day) increase the l i k e l i hood of freezing at the interface between a i r and s o i l .  The i n s u l a t i n g q u a l i t i e s  of d e t r i t u s i n h i b i t thermal inputs during the day and, in cold regions, retard  96 microbial a c t i v i t y c r i t i c a l in nutrient m i n e r a l i z a t i o n . i s strongly dependent on s o i l temperature.  A l s o , root metabolism  Nutrient uptake, p a r t i c u l a r l y that  of P, i s strongly i n h i b i t e d by low s o i l temperatures. Perhaps even more c r i t i c a l than the thermal e f f e c t s of d e t r i t u s accumul a t i o n are the attendant e f f e c t s of nutrient immobilization in undecomposed d e t r i tus.  The rates of d e t r i t a l accumulation, however, were not i n d i c a t i v e of nut-  r i e n t accumulation in d e t r i t u s .  For example, on the subalpine reclaimed area  net accumulation of d e t r i t u s over the year was 122 g m plot while the f e r t i l i z e d p l o t l o s t 17 g m  of d e t r i t u s .  showed the greatest increase on the f e r t i l i z e d p l o t .  on the u n f e r t i l i z e d However, d e t r i t u s N  So the more rapid d e t r i t u s  decomposition on the f e r t i l i z e d p l o t was more than compensated for by the i n crease in d e t r i t a l N concentration.  The concentration in d e t r i t u s also i n -  creased on the f e r t i l i z e d p l o t so that the accumulation of d e t r i t a l P was s i m i l a r in both p l o t s .  D e t r i t a l N also increased on both montane reclaimed plots while  d e t r i t a l P decreased. The greater accumulation of d e t r i t a l nutrients on f e r t i l i z e d plots may be misleading.  For with higher N and P concentrations and consequent narrowing of  C:N, P r a t i o s decomposition w i l l l i k e l y proceed at a higher rate than on the unfertilized plots.  So, on the u n f e r t i l i z e d plots nutrients contained in de-  t r i t u s were less mobile and d e t r i t u s was more l i k e l y to act as a n u t r i e n t sink. Another c r i t i c a l area l i e s in the r e l a t i v e amounts of nutrients bound in d e t r i t u s . On the subalpine reclaimed area more N accumulated in d e t r i t u s on the f e r t i l i z e d p l o t than on the u n f e r t i l i z e d p l o t .  However, on the f e r t i l i z e d p l o t d e t r i t a l N  accumulation amounted to 20% of the y e a r ' s shoot N uptake while 86% of shoot N uptake was s t i l l i n the d e t r i t u s pool by October on the u n f e r t i l i z e d p l o t . Both montane and subalpine reclaimed areas showed large net increases in d e t r i t a l N over the year.  However, the October to May period was one of s i g n i f i -  cant d e t r i t a l decomposition and nutrient release on the montane area while v i r t u a l l y no d e t r i t a l decomposition occurred on the subalpine reclaimed  97  area during t h i s period. Unlike N and P, K did not accumulate in d e t r i t u s .  Although d e t r i t u s mass  varied widely throughout the study period d e t r i t a l K l e v e l s on a l l plots generally _2 remained near 1 g m shoots.  .  This suggests that K leaches r e a d i l y from newly-fallen  Also, K may leach from l i v e shoots and may be e f f i c i e n t l y translocated  to l i v e plant parts p r i o r to senescence. These r e s u l t s suggest that, r e l a t i v e to both shoot and root N requirements, a substantial amount of previously mobile N w i l l be immobilized in d e t r i t u s on the subalpine reclaimed area i f f e r t i l i z a t i o n i s discontinued.  P i s bound to a  lesser extent in d e t r i t u s and K i s not immobilized to any s i g n i f i c a n t degree. The paucity of legumes on the high-elevation area w i l l aggravate  N-deficiencies  in the future. On the montane reclaimed area net production continued at high l e v e l s without f e r t i l i z a t i o n and nutrients showed no evidence of accumulating to any great extent.  Also, f e r t i l i z a t i o n of the montane reclaimed area affected the  a l l o c a t i o n of photosynthate and n u t r i e n t s .  F e r t i l i z a t i o n tended to increase  shoot and d e t r i t u s production at the expense of root production. of t h i s new shoot material i s taken as the explanation.  Drought-killing  A l s o , the large legume  component of the montane reclaimed area w i l l help maintain nutrient s e l f - s u f ficiency. 6.2  FATE OF APPLIED NUTRIENTS Nutrients applied to a plant community are subject to s i x f a t e s :  1) plant  uptake, 2) erosion, 3) deep leaching, binding in the s o i l in e i t h e r 4) a v a i l a b l e or 5} unavailable forms and, in the case of N, 6) v o l a t i l i z a t i o n .  Fates 1 and 4  represent gains to the plant community while the r e s t are i r r e v e r s a b l e losses and some may even degrade surrounding surface or ground waters. Nutrient losses, p a r t i c u l a r l y those of deep leaching, v o l a t i l i z a t i o n and s o i l tieup are nearly impossible to measure d i r e c t l y . r i e n t losses and gains were estimated by inference.  To avoid this, problem nutF i r s t , shoot and root "uptake"  98 were estimated by adding the nutrient increases in these compartments for each sampling i n t e r v a l between October 1976 and October 1977 which showed a net gain. Shoot and root uptakes of u n f e r t i l i z e d and f e r t i l i z e d paired plots were then subtracted to y i e l d an estimate of " f e r t i l i z e r e f f e c t " .  F e r t i l i z e r e f f e c t was  then divided by the amount of added nutrient and m u l t i p l i e d by 100 to y i e l d an estimate of " f e r t i l i z e r e f f i c i e n c y " . This approach was taken with the understanding that net uptake as used here is l a r g e l y a function of sampling frequency and the integration i n t e r v a l . And, as the i n t e r v a l increases, estimates of net uptake become less  sensitive  to short term f l u c t u a t i o n s . Mindful of these constraints, n u t r i e n t uptake, f e r t i l i z e r e f f e c t and f e r t i l i z e r e f f i c i e n c y are discussed in the following s e c t i o n . 6.2.1  Nitrogen A l l areas except for the montane reclaimed area registered high f e r t i l i z e r  N e f f i c i e n c i e s (Table 12).  The highest e f f i c i e n c y was apparent in the subalpine  reclaimed area where 71% of added N was u t i l i z e d by the plant community. ever, 78% of N uptake was s t i l l  in shoots at the end of the study while the r e -  maining 22% went to the root compartment.  While t o t a l N uptake increased 370%  on the subalpine reclaimed area, f e r t i l i z a t i o n also caused root:shoot r a t i o s to reverse.  How-  N-uptake  On the f e r t i l i z e d p l o t the rootrshoot N-uptake r a t i o was 35:  65 while i t was 60:40 i n the u n f e r t i l i z e d p l o t . On the native plots f e r t i l i z a t i o n resulted in a s l i g h t s h i f t in the d i s t r i b u t i o n of N-uptake.  For example, on the montane native area the root:shoot  N-uptake r a t i o changed from 92:8 to 87:13 as the r e s u l t of f e r t i l i z a t i o n .  These  data indicate the dominant r o l e played by roots of these mountain grasslands in N-uptake, storage and release. Only the montane reclaimed area showed a net loss of N due to f e r t i l i z a t i o n . F e r t i l i z a t i o n resulted in a large gain in shoot N but an even larger loss in root N r e l a t i v e to the u n f e r t i l i z e d p l o t .  Thus, the net f e r t i l i z e r e f f e c t was -0.07 g m  99  Table  12.  Estimated f e r t i l i z e r and e f f i c i e n c y .  SHOOT UPTAKE (g m-2)  N uptake,  effect  ROOT TOTAL PLANT + UPTAKE = UPTAKE ( g m-2) ( g rn- ) 2  Montane N a t i v e Fertilized '  cr .20 j  34 .72  39.92  Nonfertilized  2 .64  30 • 25 4 .47  32.89  "Fertilizer  Effect"  "Fertilizer  Efficiency"  Montane  2 .56  54 .1%  Reclaimed  Fertilized  5,.53  Nonfertilized  3..82  "Fertilizer  Effect"  "Fertilizer  Efficiency"  Subalpine  7.03  1..71  .6, .13 7.• 9 1 - 1 . .78  11.66 11.73 -  .07 0%  Native  Fertilized  3 . 79  4 6 . 15  49 .94  Nonfertilized  1. 84  4 2 . 02  43.86  1. 9 5  4 . 13  6.08  "Fertilizer "Fertilizer Subalpine  Effect" Efficiency"  46.8%  Reclaimed  Fertilized  8. 52  4 . 12  Nonfertilized  1. 34  2 . 08  3. 4 2  7 . 18  2. 04  9 .22  "Fertilizer  Effect"  "Fertilizer  Efficiency"  12.64  70.9%  . 100 y i e l d i n g 0% f e r t i l i z e r e f f i c i e n c y .  The influence of drought on t h i s phenomenon  has been discussed i n previous sections. Perhaps as surprising as the negative f e r t i l i z e r e f f i c i e n c y on the montane reclaimed area were the high e f f i c i e n c i e s on the other areas.  Fertilizer  e f f i c i e n c y was probably a function of two major f a c t o r s : s o i l moisture and nutr i e n t competition from non-vascular users (decomposers).  S o i l s on the two native  areas and the subalpine reclaimed area seemed to remain at l e a s t palpably moist throughout the summer.  The native area s o i l s were r i c h in organic matter which  tended not only to capture and hold moisture but also served as substrate f o r decomposers.  Thus, f e r t i l i z e r N-efficiency was lower on the native areas than  on the subalpine reclaimed area which was w e l l - s u p p l i e d with s o i l moisture throughout the summer while nearly devoid of s o i l organic matter. A high rate of f e r t i l i z e r N (130 kg ha~^) was applied in t h i s study. This i s roughly 500% of Kaiser Resources' normal rate of N - f e r t i 1 i z a t i o n .  That  even at this level high N uptake e f f i c i e n c i e s were achieved suggests several conclusions. F i r s t , in vigorously growing reclamation plant communities normal rates of N - f e r t i l i z a t i o n w i l l be quickly incorporated by the plants r e s u l t i n g in i n s i g n i f i c a n t N-losses v i a v o l a t i l i z a t i o n , leaching or f i x a t i o n .  Of p a r t i c u l a r con-  cern p r i o r to the study were the extent of N-losses due to the v o l a t i l i z a t i o n of NHg.  The reclamation " s o i l s " were basic and tended to become warm and dry  in mid-summer, perfect conditions for the oxidation of NH^.  F e r t i l i z e r was ap-  p l i e d during a very l i g h t rain so that nearly optimal conditions for f e r t i l i z a t i o n prevailed.  Also, because the three plant communities were able to accelerate  N-uptake rates l i t t l e applied N v/as a v a i l a b l e f o r leaching or v o l a t i l i z a t i o n . S i g n i f i c a n t loss of t h i s sort may well have occurred on the montane reclaimed area where enough N entered the plants to shrink the root systems and accelerate shoot growth.  However, this probably represented only a f r a c t i o n of applied N.  In order to make f e r t i l i z a t i o n more e f f i c i e n t N should be applied, along with  101 the other n u t r i e n t s , e a r l i e r in the season.  Regular maintenance f e r t i l i z a t i o n  of these areas i s usually applied sometime in June.  This caused the f e r t i l i z e d  area to begin rapid shoot growth j u s t before the drought period began.  Con-  sequently, that N which was u t i l i z e d tended to work to the detriment of the plant community while most of the applied N was probably l o s t via v o l a t i l i z a t i o n .  In  a wetter year t h i s l a t e a p p l i c a t i o n date might not have had such adverse e f f e c t s . However, the c l i m a t i c data indicate that the July drought i s a regular occurrence. In order to maximize u t i l i z a t i o n of added N p r i o r to the drought period future f e r t i l i z a t i o n of the low to mid-elevation s i t e s should, i d e a l l y , be completed by the t h i r d week of May.  Thus, the plants would have both moisture and nutrients  during the maximum growth period of l a t e May to l a t e June.  F e r t i l i z a t i o n of sub-  alpine areas should be completed by the f i r s t week of June. 6.2.2  Phosphorus Compared to N, the u t i l i z a t i o n of applied P was extremely low.  The highest  f e r t i l i z e r P e f f i c i e n c y was measured on the subalpine native p l o t at 36%. subalpine reclaimed area was 16% and the montane native area only 7%.  The  As was  the case with N the montane reclaimed area showed a net decrease in P uptake due to f e r t i l i z a t i o n (Table 13). The high l e v e l s of Ca i n a l l of these s o i l s undoubtedly influenced the low P uptake rates.  High s o i l Ca l e v e l s combined with surface a p p l i c a t i o n would  tend to maximize calcium phosphate formation and thus remove a large part of the added P from the nutrient cycle. That f e r t i l i z a t i o n resulted in a doubling of shoot P uptake in the montane native area yet a s l i g h t decrease i n root P uptake suggests that the plant community was already w e l l - s u p p l i e d with a v a i l a b l e P without f e r t i l i z a t i o n .  The ad-  d i t i o n of f e r t i l i z e r caused a doubling of shoot mass and the P demands of the added mass were met with no increase of shoot or root P concentration. The rate of shoot P uptake also doubled on the montane reclaimed area after f e r t i l i z a t i o n .  However, the rate of root P uptake dropped f a r below that  102  Table 1 3 .  Estimated f e r t i l i z e r and e f f i c i e n c y .  P uptake,  SHOOT UPTAKE + (g rn" ) 2  effect  ROOT TOTAL PLANT UPTAKE = UPTAKE ( g m-2) ( -2) g  m  Montane N a t i v e Fertilized  .82  Nonfertilized "Fertilizer  Effect"  "Fertilizer  Efficiency"  Montane  2 .34  3.16  .34  2 .36  2.70  .48  — • .02  .46  6.7%  Reclaimed  Fertilized  .  Nonfertilized "Fertilizer  Effect"  "Fertilizer  Efficiency"  Subalpine  '  .54  .67  1.21  .25  .99  1.24'  .29  - • 32  -  .03  .0 58  Native  Fertilized  .48  5 .20  5.68  Nonfertilized  .27  2 .95'  3.22  . 21  2 .25  2.46  "Fertilizer  Effect"  "Fertilizer  Efficiency"  Subalpine  -  35:M  Reclaimed  Fertilized  .75 •  .92  Noiif e r t i l i z e d  .26  • 31  .49  .61  "Fertilizer  Effect"  "Fertilizer  Efficiency"  1.67 .'57 1.10 16.0%  .  103 of the u n f e r t i l i z e d plot y i e l d i n g a s l i g h t net decline in P uptake due to f e r t ilization.  As was true of N uptake on t h i s area f e r t i l i z a t i o n had l i t t l e e f f e c t  on the net plant P uptake.  Rather, f e r t i l i z a t i o n influenced the p a r t i t i o n i n g  of the incorporated n u t r i e n t s . In the case of both N and P the r e p a r t i t i o n i n g involved a massive diversion of nutrient to the shoots at the expense of the roots.  Since the root systems of the reclaimed plant communities were already  small t h i s trend could have an adverse e f f e c t on i t s a b i l i t y to withstand f u r ther drought and to store carbohydrates and nutrients over winter.  Also, i f  continued, t h i s phenomenon would tend to drive the plant processes away from those displayed in the native areas.  So, f e r t i l i z a t i o n induced, on the reclaimed  areas at l e a s t , a detritus-based nutrient c y c l e .  Whereas n u t r i e n t exchanges v i a  the d e t r i t u s compartment were minor in r e l a t i o n to those of the root compartments of native areas, on reclaimed areas nutrient f l u x v i a the d e t r i t u s pool was only s l i g h t l y smaller than root f l u x for N and was equal to root f l u x for P.  Part-  i c u l a r l y on the montane reclaimed area, f e r t i l i z a t i o n tended to accelerate t h i s process.  In short, i f the nutrient exchange processes of the native grasslands  were i n d i c a t i v e of stable grasslands in t h i s region then continued f e r t i l i z a t i o n , at l e a s t of the montane reclaimed area, i s a d e s t a b i l i z i n g f a c t o r . The case of the subalpine reclaimed area was quite d i f f e r e n t .  There, N  and P levels in the plant community were so low that f e r t i l i z a t i o n resulted in large gains to the root system.  Also, s o i l moisture was s u f f i c i e n t that drought  e f f e c t s did not confound f e r t i l i z a t i o n e f f e c t s .  The subalpine area may well r e -  present a plant community in the early stages of development, as evinced by the n e g l i g i b l e annual root a t t r i t i o n .  The montane reclaimed area, however, underwent  a large root a t t r i t i o n in the f a l l of 1976 and 1977.  This suggests that the mon-  tane reclaimed area has reached a degree of maturity and supports as much biomass as i t possible under the circumstances.  In other words, the montane reclaimed  area has developed to the point where factors other than nutrient a v a i l a b i l i t y l i m i t sustainable biomass.  The dominant factor among these i s , doubtless, s o i l  104 moisture.  Thus, any increment in a v a i l a b l e s o i l nutrient l e v e l s has no influence  on standing crop.  Rather, i t merely r e p a r t i t i o n s the standing crop.  In t h i s  case, the r e p a r t i t i o n i n g occurred to the detriment of the plant community. For the subalpine reclaimed area, in contrast, a v a i l a b l e s o i l n u t r i e n t s , p a r t i c u l a r l y N and P, were s t i l l the dominant l i m i t i n g f a c t o r s .  Consequently,  f e r t i l i z a t i o n increased net production and sustainable standing crop.  As the  previous discussions i n d i c a t e d , decomposition and n u t r i e n t m i n e r a l i z a t i o n were r e s t r i c t e d on this area.  This tendency w i l l probably continue.  Thus, N and P  a v a i l a b i l i t y w i l l continue to be c r i t i c a l l i m i t i n g factors to production on the subalpine reclaimed areas. 6.2.3  Potassium The e f f i c i e n c y of f e r t i l i z e r K uptake was high on only the subalpine r e -  claimed area.  On the subalpine native area i t was 0% while only 26% on the mon-  tane native area (Table 14).  K was the only nutrient which showed any e f f i c i e n c y  of uptake on the montane reclaimed area. c l i n e d due to f e r t i l i z a t i o n .  On both native areas root K uptake de-  Except for the subalpine native area a l l areas  showed strong increases i n shoot K uptake due to f e r t i l i z a t i o n .  The low u t i l i -  zation rate of K in the native areas and the montane reclaimed area supports the argument, presented in e a r l i e r sections, that f e r t i l i z e r K entered into an e q u i l ibrium between slowly a v a i l a b l e and a v a i l a b l e form.  This explanation would pre-  suppose the presence of expanding-lattice clays in substantial q u a n t i t i e s .  That  f e r t i l i z a t i o n resulted in a net p o s i t i v e uptake on the montane reclaimed area r e f l e c t s i t s strong translocation to the shoots.  Thus, even though f e r t i l i z a t i o n  caused a loss in net root production on t h i s area, t h i s had l i t t l e e f f e c t on the net plant uptake of K. In conclusion, f e r t i l i z a t i o n had a s l i g h t p o s i t i v e e f f e c t on root K uptake on the reclaimed areas while i t caused a minor decrease in root K uptake in the native areas.  In contrast, f e r t i l i z a t i o n tended to increase shoot K uptake.  Whether t h i s increase in shoot K uptake was merely "luxury consumption" or  105  T a b l e '14 .  Estimated f e r t i l i z e r and e f f i c i e n c y .  K uptake,  effect  SHOOT ROOT TOTAL PLANT UPTAKE + UPTAKE = UPTAKE (g rn" ) ( g m-2) (g - 2 ) 2  m  Montane N a t i v e Fertilized  6 .96  2 .47  9.43  Nonfertilized  3 .24  3 .98  7 . 22  - l .51  2 . 21  "Fertilizer  Effect"  "Fertilizer  Efficiency"  Montane  3 .72  26.5%  Reclaimed  Fertilized  4 .20  1 .86  6.06  Nonfertilized  2 .55  1 .78  4.33  1 .65  .08  1.73  "Fertilizer  Effect"  "Fertilizer  Efficiency"  Subalpine  Native  Fertilized  .  Nonfertilized "Fertilizer  Effect"  "Fertilizer  Efficiency"  Subalpine  20.8%  s  2 .23  3 .27  5-50  2 .49  4 .25  6.74  - .26  - .98 .  -1.24 0 35  Reclaimed  Fertilized  10 . 6 2  Nonfertilized "Fertilizer  Effect"  "Fertilizer  Efficiency"  1 .10  11.72  2 .63  .67 •  3.30  7 .99  .43  8.42 101.6%  106  benefited the plant community i s uncertain. 6.3  SUMMARY OF DISCUSSION A c l e a r picture of two types of grass-forb communities emerged in the  foregoing discussion.  The two community types appear s i m i l a r from the surface  and even maintained s i m i l a r shoot standing crops in summer.  However, in terms  of community function (net production, decomposition and nutrient cycling) they were very d i f f e r e n t . The native areas represent the f i r s t functional type.  Its most outstanding  feature was the dominance of below-ground plant structures in the storage and release of carbohydrates and n u t r i e n t s .  This root-based carbohydrate and nut-  r i e n t cycle i s t y p i c a l of temperate grasslands and becomes even more pronounced at high elevations and high l a t i t u d e s .  The rapid turnover of carbohydrates and  nutrients deep in the s o i l r e s u l t s in the c h a r a c t e r i s t i c Ah horizon of grassland soils.  The advantages of such a system are many.  For example, even though most  of the system's nutrients are " l o s t " each f a l l through root a t t r i t i o n the Ah horizon in r i c h in root-supplied organic matter capable of holding the mineralized cations in exchangeable form.  Also, the sloughed roots provide an a v a i l a b l e  energy source f o r decomposers which allow rapid m i n e r a l i z a t i o n so that the c y c l i n g rate of sloughed nutrients remains high. leaves the s o i l surface dry.  In these areas the dry summer often  This i n h i b i t s the decomposition of surface d e t r i t u s  and desiccates shallow rooted plants.  However, the organic matter of the native  s o i l s hold considerable moisture even during extended drought periods.  This not  only serves the plant water demands but maintains microbial a c t i v i t y and n u t r i e n t mineralization.  Also, t h i s functional type i s capable of storing a large pool  of carbohydrates and nutrients for immediate use by the plant in spring.  The a v a i l -  a b i l i t y of t h i s store i s c r i t i c a l since in t h i s region, the optimal growth period i s compressed between the long winter and the dry summer.  Consequently, the plants  must be able to photosynthesize most of t h e i r annual carbohydrate needs within a roughly four-week period ( l a t e May to l a t e June).  107  The reclaimed areas represent the other functional type which became evident in t h i s study.  The type was characterized by narrow root:shoot r a t i o s .  In this type the magnitude of carbohydrate and nutrient f l u x through roots and d e t r i t u s were s i m i l a r .  Thus, while the magnitude of d e t r i t u s compartment ex-  change processes was minor in r e l a t i o n to t o t a l community f l u x on the native areas, i t was a major contributor to t o t a l f l u x on the reclaimed areas. dicated previously, this phenomenon can have two adverse e f f e c t s .  As i n -  F i r s t , the  surface d e t r i t u s dries out r a p i d l y and thus decomposition and nutrient minerali z a t i o n are i n h i b i t e d .  Also, since a major portion of the communities' nutrients  leach down from the s o i l surface the root system would tend to develop near the surface.  This would retard the formation of an Ah horizon and increase the  s u s c e p t i b i l i t y of the community to drought.  In short, t h i s type of plant com-  munity would be more susceptible to natural perturbations and would, therefore, be less s t a b l e .  For convenience, t h i s functional type w i l l be c a l l e d a d e t r i t u s -  root nutrient c y c l e . The causes behind the development of a root-based nutrient cycle on the native areas and a d e t r i t u s - r o o t cycle on the reclaimed areas are not c l e a r . In the early stages of primary succession p r i s t i n e grasslands may possess c y c l i n g systems s i m i l a r to those of the reclaimed areas and the root-based system may only be i n d i c a t i v e of mature grasslands on mature s o i l s .  However, i t is possible  that the d e t r i t u s - r o o t type was the r e s u l t of revegetation with agronomic forage crops which have been selected to produce l a r g e , n u t r i e n t - r i c h shoot masses. However, the r e s u l t s of this study cannot answer t h i s question since s o i l s , species and community age were unavoidably confounded. It i s c l e a r , however, that f e r t i l i z a t i o n resulted in greater carbohydrate and n u t r i e n t c y c l i n g through the d e t r i t u s compartment and narrowed root:shoot ratios.  These e f f e c t s were s l i g h t on the native areas and profound on the r e -  claimed areas.  The long-term, heavy a p p l i c a t i o n of f e r t i l i z e r to the native  areas would probably r e s u l t in changes in community composition and perhaps even  108  in a d r a s t i c s h i f t in the community's c y c l i n g system.  Such change could occur  through the invasion of species better able to u t i l i z e the highly a v a i l a b l e i n organic nutrients and to convert them into enough shoot mass to out-compete the climax perennials for l i g h t .  Indeed, the f e r t i l i z a t i o n of native ranges  has occasionally led to the invasion of "weedy" species._  F e r t i l i z a t i o n would  change the root-based c y c l i n g system from an asset to a l i a b i l i t y i n that the apportionment of most of the p l a n t ' s photosynthate to the roots at the expense of the shoots would be unnecessary for nutrient accumulation and storage.  Thus,  plant species possessing the minimum necessary root mass and maximum shoot mass would soon shade the previous climax species.  This phenomenon may e x p l a i n , in  large p a r t , the absence of s i g n i f i c a n t native grass invasion on f e r t i l i z e d r e claimed areas.  Conversely, i t seems l i k e l y that i f f e r t i l i z a t i o n on reclaimed  areas i s discontinued a f t e r adequate s o i l enrichment has occurred that the rootbased system would slowly encroach.  The encroachment process would, of course,  be accelerated by d i s t r i b u t i o n of the appropriate propagules. The tendency of f e r t i l i z a t i o n to induce a d e t r i t u s - r o o t cycle figures in the development of the reclaimed areas as w e l l .  Within these plant communities  there appeared to be a development phase, when maintenance f e r t i l i z a t i o n resulted in a net accumulation of perennating structure and n u t r i e n t s , and a mature phase when maintenance f e r t i l i z a t i o n was unnecessary and even i n h i b i t e d further development.  The subalpine reclaimed area represented development phase and the  montane reclaimed area the mature phase. In the development phase the plant community has not accumulated enough carbohydrate and n u t r i e n t s ; nor has i t s u f f i c i e n t l y enriched the s o i l that i t can survive the interruption of maintenance f e r t i l i z a t i o n without serious d i s ruption.  Thus, during the development phase maintenance f e r t i l i z a t i o n is  critical.  The adverse e f f e c t s of f e r t i l i z a t i o n of a mature area have already been discussed though, in t h i s case, drought aggravated the e f f e c t s of f e r t i l i z a t i o n .  Proof  that these two reclaimed area are in the suggested developmental states w i l l be  109 i n t h e i r future performance without f e r t i l i z a t i o n . Monitoring data on these areas are now a v a i l a b l e f o r the summer of 1978 (Fyles, 1979).  The data i n d i c a t e that, indeed, the montane reclaimed area main-  tained i t s 1977 level of net production without f e r t i l i z a t i o n while net production continued to decline on the subalpine reclaimed p l o t . Though these two areas both received i n i t i a l reclamation treatments in 1974 t h e i r l e v e l s of development were very d i f f e r e n t between 1976 and 1978.  This  was due to the retarding e f f e c t of the c o l d , dry subalpine environment on the development of reclamation plant communities.  The combination of cold and sur-  face dessication aggravated problems associated with the d e t r i t u s - r o o t n u t r i e n t cycle in that a large part of the system's nutrients were t i e d up in undecomposed surface d e t r i t u s .  Indeed, the subalpine climate of this region may ensure that  these reclaimed areas w i l l never reach the mature stage of the montane reclaimed areas.  The solution to t h i s problem may well l i e in the use of adapted native  herbaceous species which w i l l a l l o c a t e a greater portion of t h e i r photosynthate to the root system and, s a c r i f i c i n g shoot production, thus develop a root-based nutrient c y c l e . The persistance of the mature phase on the montane reclaimed area i s not certain.  It is possible that, for example, with i t s shallow root system a three  to four year period of very dry summers could cause severe damage.  However, i t  seems more l i k e l y that these plant communities w i l l p e r s i s t f o r a considerable time.  Eventually they w i l l probably be supplanted by l o c a l ecotypes which are  p h y s i o l o g i c a l l y , reproductively and morphologically better adapted to the region. 7.0  IMPLICATIONS FOR RECLAMATION Perhaps the most s i g n i f i c a n t r e s u l t of t h i s study was the development of  a method by which the degree of nutrient s t a b i l i t y and maturity of reclaimed areas can be assessed.  Two d i s t i n c t phases in the development of reclamation  plant communities were i d e n t i f i e d . The immature phase i s characterized by a small root system that undergoes  110  l i t t l e y e a r l y a t t r i t i o n , and a major portion of the system's a v a i l a b l e nutrients are transferred from the shoots to the d e t r i t u s in the f a l l .  Consequently, un-  less rapid d e t r i t a l decomposition occurs the plant community becomes nutrient d e f i c i e n t and quickly loses p r o d u c t i v i t y .  N and P are immobilized to the great-  est extent in surface d e t r i t u s while K i s leached from the d e t r i t u s . decomposition of d e t r i t u s i s aggravated by cold and dry conditions.  The slow Therefore,  the high elevation areas are most l i k e l y to experience N and P d e f i c i e n c i e s and require longer periods of maintenance f e r t i l i z a t i o n , p a r t i c u l a r l y with N and P. The mature phase i s recognized by a larger root system which undergoes a high rate of turnover each year.  Since the large root turnover places in the  s o i l a large cycling pool of nutrients which mineralize r a p i d l y , these communities no longer require maintenance f e r t i l i z a t i o n .  Indeed, f e r t i l i z a t i o n in a drought  year can damage a mature reclaimed area. Knowing that root and d e t r i t a l dynamics are the key areas f o r nutrient c y c l i n g in these reclaimed areas i t i s necessary only to sample shoots, roots and d e t r i t u s f o r a f u l l year or more.  Chemical analysis of this material pro-  vides helpful information and should be carried out in an area where no previous work has been done.  However, once the n u t r i e n t concentrations are established  further analyses may be unnecessary as nutrient concentrations tended to remain stable for given phenological events.  Estimates of s o i l nutrient l e v e l s tended  to vary widely and were d i f f i c u l t to i n t e r p r e t due to t h e i r low p r e c i s i o n . Generally, there was l i t t l e c o r r e l a t i o n between s o i l nutrient estimates and plant behavior or d e t r i t a l decomposition.  In future studies t h i s aspect should  receive less a t t e n t i o n . Mature reclamation plant communities should not be f e r t i l i z e d . plant communities should be.  Immature  While there i s no i n d i c a t i o n of how long the mature  communities w i l l p e r s i s t , they w i l l l i k e l y p e r s i s t at l e a s t several years a f t e r f e r t i l i z a t i o n i s discontinued with l i t t l e drop in p r o d u c t i v i t y .  The immature  communities w i l l decline r a p i d l y in p r o d u c t i v i t y immediately a f t e r the discontinuance  Ill  of f e r t i l i z a t i o n .  They w i l l not, however, die o f f immediately.  Most of the  plants w i l l survive for at l e a s t two years though production w i l l f a l l  drast-  ically. Immature reclamation plant communities do not necessarily become mature plant communities.  At subalpine and alpine locations reclamation plant commu-  n i t i e s may never become mature u n t i l adpated native species become established. This i s an area of research that requires a great deal more a t t e n t i o n . The overburden in t h i s area i s calcareous. applied P i s bound in unavailable form in the s o i l .  So, most of the surfaceIn the currently-used f e r t -  i l i z e r mix (13-16-10) there i s only h a l f as much P as N. zation even less P i s a v a i l a b l e to the plant.  Due to s o i l immobili-  Therefore, 13-16-10 a p p l i c a t i o n  provides the plant with a disproportionate amount of N and very l i t t l e P.  Since  surface broadcast application is the only p r a c t i c a l method of applying maintenance f e r t i l i z a t i o n this problem might only be a l l e v i a t e d by using a f e r t i l i z e r with a higher percentage of P. supply.  K cycles r a p i d l y and did not appear to be in short  However, even with K additions each year the legumes have become dras-  t i c a l l y less abundant on a l l reclaimed areas.  This may not be due to competition  with the grasses for K, but as long as N i s added y e a r l y , K should be added as well i f only as a precaution. on reclaimed areas.  K-deficiency symptoms were observed i n legumes  Therefore, a f e r t i l i z e r grade or mixture y i e l d i n g approxi-  mately 10-40-10 i s recommended. Maintenance f e r t i l i z a t i o n should be completed by the t h i r d week of^May on the low elevation areas and the f i r s t week of June on the high elevation areas.  These dates usually coincide with the f i r s t evidence of shoot growth on  the reclaimed areas. eral weeks.  Since large areas are f e r t i l i z e d the process can take sev-  Therefore, some areas are f e r t i l i z e d too early and some too l a t e .  For this reason dates were suggested for the completion of f e r t i l i z a t i o n since waiting for the evidence of shoot growth w i l l guarantee that some areas are not f e r t i l i z e d u n t i l l a t e June.  Early f e r t i l i z a t i o n w i l l r e s u l t in some f e r t i l i z e r  . 112 loss but this i s considered minor compared to the damage done by l a t e f e r t i l i zation.  A l s o , e l i m i n a t i o n of maintenance f e r t i l i z a t i o n on many of the montane  areas w i l l shorten the time required to complete the annual f e r t i l i z a t i o n program.  E a r l i e r f e r t i l i z a t i o n w i l l mitigate the tendency of f e r t i l i z a t i o n to ex-  tend the growth period into the summer drought period at low elevations and i n t o f a l l at high elevations. "Top dressings" of ammonium sulphate or ammonium n i t r a t e are sometimes applied in mid-summer when the plants begin to look c h l o r o t i c .  This p r a c t i c e  should be discontinued as the chlorosis i s the r e s u l t of drought-induced dormancy.  Any attempt to break t h i s dormancy by top dressing to cause a "greening"  of the reclaimed area only damages the root systems. The immature plant community monitored in t h i s study was capable of absorbing much more f e r t i l i z e r than i s usually added i n maintenance a p p l i c a t i o n s . However, most of the additional N remained in the shoots u n t i l f a l l when i t was f r o s t k i l l e d , whereas a majority of the added P resided in the roots by the f a l l This suggests that greater additions of P could be retained by the plants while large N additions are wasted.  Therefore, the current rate of 200 kg 13-16-10  ha~* should be raised to about 300 kg 10-40-10 h a " * .  This would increase added  N s l i g h t l y and increase P by 370% thereby accelerating development of a vigorous root system.  Also, by stopping the practice of top dressing the onset of f a l l  dormancy should be hastened. 8.0 1.  CONCLUSIONS F e r t i l i z a t i o n stimulated the production of shoot mass on both native and reclaimed areas.  Where s o i l moisture was l i m i t i n g (montane reclaimed area)  the increase in shoot production did not r e s u l t in greater mid-summer standing crops.  Rather, i t merely accelerated nutrient and carbohydrate  f l u x through the shoot compartment and increased additions to the d e t r i t u s pool.  The maintenance of a high shoot production caused a reduction of net  root production.  On the other study areas, though f e r t i l i z a t i o n narrowed  113 root:shoot ratios i t also increased net root production. tended to accelerate d e t r i t a l decomposition.  F e r t i l i z a t i o n also  On a l l study s i t e s  fertilization  caused l a r g e r shoot masses to p e r s i s t into the f a l l , thus f a l l dormancy was delayed. 2.  Even at the high f e r t i l i z a t i o n rates used in t h i s study plant uptake of N was high suggesting l i t t l e N-loss v i a v o l a t i l i z a t i o n or leaching. drought-affected montane reclaimed area did not follow t h i s trend.  The Rather,  f e r t i l i z a t i o n resulted in a net loss of N to the plant community.  P uti-  l i z a t i o n was low due to the surface a p p l i c a t i o n of P on calcareous  soils.  Thus, phosphates were immobilized by Ca and Mg.  K u t i l i z a t i o n was high on  the subalpine reclaimed area and low elsewhere. 3.  The native and reclaimed areas d i f f e r e d dramatically in net p r o d u c t i v i t y and the a l l o c a t i o n of photosynthate.  The native areas were much more pro-  ductive with most of the photosynthate translocated to t h e i r massive root systems. 4.  The differences in plant phenology and morphology between native and reclaimed areas resulted in d i f f e r e n t systems f o r nutrient and carbohydrate c y c l i n g . The native areas possessed a root-based cycle i n which the bulk of the annual turnover of nutrients and carbohydrates occurred below-ground.  On the r e -  claimed areas roughly equal portions of the system's nutrients and carbohydrates were released via the d e t r i t u s and root pools. 5.  Factors which affected surface d e t r i t u s decomposition were, thus, c r i t i c a l in determining the rate of nutrient c y c l i n g and the degree of nutrient s e l f s u f f i c i e n c y on the reclaimed areas. another c r i t i c a l f a c t o r .  The p r o d u c t i v i t y of root systems was  Reclaimed areas which, without maintenance f e r t -  i l i z a t i o n , showed vigorous root growth in spring and nearly equal f a l l a t t r i t i o n and which apparently reached steady state d e t r i t u s l e v e l s were considered "mature".  Reclaimed areas with small root systems which under-  went neither rapid spring growth nor major f a l l a t t r i t i o n and which accumulated  114  d e t r i t u s throughout the study were considered "immature". Immature reclamation plant communities of t h i s area accumulate, with annual f e r t i l i z a t i o n , carbohydrates in the root and surface d e t r i t u s pools.  If the  communities develop s u f f i c i e n t l y , a mature stage i s reached where, without f e r t i l i z a t i o n , decomposition roughly matches shoot inputs to d e t r i t u s and d e t r i t u s ceases to accumulate upon reaching steady state l e v e l s .  Also, as  the root systems develop to a mature state a large r o o t - s o i l - r o o t exchange system develops. Immature plant communities require maintenance f e r t i l i z a t i o n , mature communities do not. Even the mature reclamation plant communities are not as stable as native grasslands.  They w i l l continue to be more susceptible to drought and do not  have the massive carbohydrate and nutrient pools c h a r a c t e r i s t i c of the native areas.  At the mature stage, when maintenance f e r t i l i z a t i o n i s discontinued  e f f o r t s can be made to introduce native species to the reclaimed area. At l e a s t in subalpine and montane areas of southeastern B r i t i s h Columbia e f f o r t s to introduce native species while f e r t i l i z a t i o n i s s t i l l practiced w i l l r e s u l t in minimal success unless competition from the agronomic species  is  reduced. Immature reclamation areas w i l l not necessarily develop into mature plant communities.  Factors retarding d e t r i t a l decomposition, low temperatures  and moisture may ensure that, with current reclamation p r a c t i c e s , subalpine and alpine reclaimed areas w i l l never mature or w i l l do so very slowly. Native and reclaimed plant community dynamics w i l l change even short d i s tances from the study area.  Therefore, s i m i l a r studies done elsewhere should  begin with a s i m i l a r l y high sampling i n t e n s i t y . While the results of this study w i l l be important to reclamation planning on the study area, the main contribution of this work l i e s in the i d e n t i f i c a t i o n of a method which, within a r e l a t i v e l y short time, can give a better  115 understanding of the development c f reclamation plant communities than has hitherto been possible.  The applications outside the f i e l d of reclamation  are numerous, though i t is s u f f i c i e n t that a method now exists by which s e l f s u f f i c i e n t reclamation plant communities can be i d e n t i f i e d . 9.0  AREAS FOR FURTHER RESEARCH The methods developed in this study have wide application.  In the f i e l d  of reclamation the following research may now y i e l d valuable results: A.  The contribution of genetics in determining plant phenology and eventual nutrient s e l f - s u f f i c i e n c y . 1.  Do native herbaceous species posses adaptive features which accelerate the development of nutrient s e l f - s u f f i c i e n c y ( i . e . greater internal- ' cycling, more rapid entry into winter dormancy, greater a l l o c a t i o n of photosynthate and nutrients to the roots)?  2.  If these characteristics e x i s t , are they s i g n i f i c a n t at the community level of integration?  B.  What maintenance f e r t i l i z a t i o n programs optimize the development of nutrient s e l f - s u f f i c i e n c y ? 1.  Effects of f e r t i l i z e r grade, rate and maintenance period on community function.  2.  The r e l a t i v e nutrient requirements c f native and agronomic reclamation plant communities.  These questions could be answered in simple, though long-term, studies. Mixtures of appropriate native and agronomic species could be sown on overburden and mature, devegetated s o i l .  The use of a range of f e r t i l i z e r rates, grades  and maintenance periods would complete the treatments.  Monitoring of the shoot,  root and detritus pools over time wou'd illuminate most of the questions answered by t h i s study.  left  116 10.0  LITERATURE CITED  Ahlgren, I.F. and Ahlgren, C E . 1960. f i r e s . Bot. Rev. 26:483-533.  Ecological e f f e c t s of forest  Aleksandrova, V.D. 1970a. 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Annual increase of underground materials in three range grasses. Ecology 27:115-127. Woodwell, G.M. and Botkin, D.B. 1970. Metabolism of t e r r e s t r i a l ecosystems by gas exchange techniques: the Brookhaven approach. J_n. D.E. Reichle (ed.). Analysis of Temperate Forest Ecosystems. Springer-verlag. New York, N.Y. Younkin, W.E. 1976. (ed.). Revegetation Studies in the Northern MacKenize Valley Region. A r c t i c Gas Biophysical Rep. Series 38:4-20.  128  Appendix I.  The d i s t r i b u t i o n of N, P, K, Ca and Mg (g m~ ) i n the shoot, d e t r i t u s , root and s o i l compartments from August 1976 to October 1977, the s o i l data represent the means of three samples and are followed by the standard dev i a t i o n of the mean and the 90% confidence l i m i t s . F and NF designations represent f e r t i l i z e d and n o n - f e r t i l i z e d plots respectively.  129  NITROGEN (G M**-2) MONTANE NATIVE F  AUG OCT MAY JUN AUG OCT  DETSHOOT+RITUS+ROOT=TOTAL 4.48 7. 88 31. 28 43. 64 1. 18 5. 94 16. 19 23.31 1.90 1 1. 71 12. 26 25.86 6.38 7.11 46.98 60.47 5.52 10. 49 33. 66 49. 67 1. 63 6. 29 25. 84 33. 77  90% CONFIDENCE LIMITS X SX LOWER UPPER 740. 32 107. 77 425.63 1055.01 755.33 78. 46 526.23 984.43 915. 06 75. 34 695.07 1 135.05 940.24 36. 71 833.05 1047.43 782. 88 75. 98 56 1. 02 1004.74 1062. 68 57.00 896.24 1229.12 SOIL  MONTANE NATIVE NF AUG 4. 98 10.82 28. 85 44. 65 606. 59 108. 38 290. 12 OCT 0.70 4.53 21.19 26.42 1290.60 93. 02 101 8.98 MAY 1. 63 16. 67 13.26 31. 56 852. 11 95. 55 573. 10 JUN 3. 34 8. 37 43.51 55. 22 664. 65 149. 09 229.31 AUG 2.12 11.16 41.54 54.83 672.24 32. 79 430.49 OCT 1.03 10.72 22.67 34.43 945.30 120. 46 593.56  923.06 1562.22 1 13 1. 12 1099.99 913.99 1297.04  MONTANE RECLAIMED F AUG 2. 53 4. 19 5. 09 OCT 1. 79 1 .76 0. 95 MAY 2. 88 3. 82 5. 34 JUN 5. 59 5. 11 7. 08 AUG 2. 16 6. 37 7. 0 3 OCT 3. 89 2. 92 4. 42  1 1. 82 4. 50 12. 03 17. 78 15. 55 11. 24  176.58 255. 33 214.56 174.06 243.57 145. 30  3. 97 48. 80 40. 56 38. 70 41.71 38. 89  164.99 112.83 96. 12 6 1.06 12 1.78 3 1.74  188. 17 397.83 333.00 287.06 365.36 258.86  MONTANE RECLAIMED NF 4. 05 AUG 3. 69 2. 02 OCT 0. 88 1 .22 1. 15 MAY 2. 55 6. 63 3. 88 JUN 4. 70 6. 02 9. 06 AUG 2. 12 4. 88 7. 72 OCT 1. 87 3. 12 5. 79  9.76 3. 26 13. 05 19.77 14. 72 10.77  407. 19 487.07 333. 13 456.64 481.27 239.78  77. 12 94. 84 37. 33 31. 38 27. 70 71.79  182.00 210. 14 224.13 36 5.01 40 0.39 30. 15  632. 38 764.00 442. 13 548.27 562. 15 449.41  130  NITROGEN (G M**-2) SUBALPINE NATIVE F DETSHOOT+aiTUS+ROOT- TOT AL 2. 53 7. 02 2 1.03 30. 63 0. 68 3. 98 6.92 11. 58 1. 45 10. 97 52.05 64. 46 4. 47 7. 40 53. 07 64. 94 4. 10 5. 11 50. 94 60. 16 3. 26 3. 61 1 9. 2926. 16  SOIL  90% CONFIDENCE LIMITS LOWER UPPER 546.54 950.60 327. 92 73 0.30 466.06 98 8.50 576.30 781.80 -133.05 930.35 55.22 1 107. 42  X 748. 57 529.11 727.28 679.05 39R.65 581.32  SX 69. 19 68. 90 89. 46 35. 19 182. 09 180. 17  32. 54 13. 18 27. 78 56.33 44. 04 18. 87  655.30 533. 72 511.71 462.35 360.89 518.08  39. 51 72. 62 59. 62 105.79 6 1. 82 80. 79  53 9.93 321.67 33 7. 62 153. 44 180.38 282.17  770. 67 745. 77 685. 80 771. 26 54 1. 40 753. 99  SUBALPINE RECLAIMED F AUG 3. 55 0. 46 0. 57 4. 59 OCT 1. 18 0. 05 0.51 1. 73 MAY 0. 70 2. 27 4. 82 1.85 6,84 JON 3. 26 12.72 2. 62 AUG 9. 22 3. 25 4. 6 3 17. 11 OCT 5. 08 1. 75 3.83 10. 67  47. 53 65. 82 55. 36 47. 34 43.27 40. 55  2. 65 8.72 2. 57 3. 31 6. 37 1.62  39.79 40,36 47. 86 37.67 24. 67 35.82  55. 27 9 1.28 62. 86 57. 01 61. 87 45. 28  SUBALPINE RECLAIMED NF AUG 2. 45 0. 35 0. 64 OCT 0. 89 0. 65 0. 48 MAY 0. 60 1. 69 1. 08 1.94 JUN 2. 40 1. 56 1.14 AUG 1. 78 2. 56 OCT 0. 77 1. 81 2. 09  48.77 70. 33 55.24 45. 82 33. 49 42. 49  6. 98 9. 59 0. 57 2. 05 5. 02 2. 14  28.39 42.33 53. 53 3 9.83 18.83 36.24  69. 15 9 3.33 56.90 51.81 48.15 48.74  :  AUG OCT MAY JUN AUG OCT  SUBALPINE NATIVE NF 2. 16 9. 10 2 1.29 AUG OCT 0. 71 4. 18 8. 29 MAY 1. 52 3. 06 23. 21 JUN 2. 55 3. 47 50. 31 AUG 1. 44 6. 35 36.25 OCT 0.39 2. 98 15. 50  .3. 44 2. 02 3. 36 5. 90 5. 47 4. 67  131  PHOSPHORUS MONTANE NATIVE F  AUG OCT MAY JUN AUG OCT  (G M**-2)  DETSHOOT+RITUS+ROOT=TOTAL 0.73 1. 12 1.85 3. 70 0.41 1. 51 3. 26 5. 18 0. 30 1 .08 1.14 2. 52 1. 12 0. 86 3. 48 5. 45 0. 73 1. 33 3.39 5. 45 0. 29 0.74 1. 34 2. 87  SOIL X 5. 27 6.54 9.45 14. 79 1. 73 5. 64  SX 0, 49 0. 62 2. 82 4. 09 1. 49 0.46  MONTANE NATIVE NF AUG 0. 85 1 . 12 1. 87 OCT 0.24 1.60 3. 47 MAY 0. 23 1 . 58 1. 30 JUN 0. 57 0. 96 3.6 6 AUG 0. 43 1.72 3. 40 OCT 0. 20 1. 49 2. 52  3. 83 5. 32 3. 11 5. 18 5. 55 4. 21  5.76 7. 89 5. 41 9.61 5. 49 5. 45  1. 03 0. 94 1. 03 4. 37 0. 92 1.55  MONTANE RECLAIMEDi F 0. 34 0.41 AUG 0.32 OCT 0. 53 0.32 0. 53 MAY 0. 32 0. 45 0.76 JUN 0. 54 0.92 0. 75 AUG 0.77 0.21 1.19 OCT 0. 53 0.31 0. 68  1. 57 1. 43 1. 53 2. 20 2. 16 1. 52  1. 59 2. 98 2.27 3. 60 6.07 3.36  0. 16 0. 63 0.30 0.79 0. 45 0. 48 .  MONTANE AUG 0. OCT 0. MAY 0. JUN 0. AUG 0. OCT 0.  1. 28 1. 99 1. 39 1. 80 2. 15 1. 71  1.72 3. 01 3. 85 1. 76 1, 99 2. 36  0. 57 0. 80 1. 44 0. 50 0. 10 0.79  RECLAIMED' NF 40 0. 40 0. 48 62 0. 81 0. 57 29 1. 10 0.50 50 0. 53 0. 76 20 0.46 1.49 24 0. 63 0. 84  90% CONFIDENCE LIMITS LOWER UPPER 3. 84 6.70 4.7 3 8. 35 1. 22 17.68 2. 85 26.73 7.38 16.08 4. 30 6.98  2.75 5. 15 2. 40 -3.15 2.80 0.92  8.77 1 0.63 8.42 22.37 8.18 9.98  1.12 1.14 1. 39 1.29 4. 76 1.96  2.06 4.82 3.15 5. 91 7.38 4.76  k  0.06 0.67 -0.35 0.30 1.70 0.05  3.38 5.35 8.05 3. 22 2. 28 4.67  132  PHOSPHORUS (G M**-2) SUBALPINE NATIVE F  AUG OCT MAY JUN AUG OCT  DETSHOOT+RITUS+ROOT= TOTAL 0.41 0.72 1.52 2. 65 0. 15 0.93 0.60 1.69 0. 20 0.99 4.73 5.92 0. 63 1. 00 5.00 6. 63 0. 56 0. 72 5. 80 7. 08 0.41 0. 42 1.87 2.70  90? X 4. 94 3.75 4. 92 12. 95 10. 17 8.31  SX 1. 96 0. 48 1. 36 2. 02 1. 98 2. 28  CONFIDENCE LIMITS LOWER UPPER -0.78 10.66 2.35 5.15 0.95 8. 89 7.05 18.85 4. 39 1 5.95 1 4.97 1.65  SOIL  SUBALPINE NATIVE NF 0. 37 0. 95 1. 54 AUG OCT 0. 23 1.03 1. 56 MAY 0. 24 0.41 1. 99 JUN 0.50 0. 43 4. 51 AUG 0.29 0.72 3. 15 0. 07 0. 37 1. 6 6 OCT  2. 86 2. 82 2. 64 5. 44 4. 16 2. 10  3. 50 3. 76 4. 25 3. 58 4. 97 1. 93  0. 63 1. 18 1. 35 0.50 2. 15 0. 91  1.66 0.31 0.31 2. 12 -1.31 -0.73  5. 34 7. 21 8. 19 5. 04 1 1.25 4. 59  SUBALPINE RECLAIMED F AUG ; 0. 64 0. 06 0. 1 1 OCT 0. 24 0. 12 0. 10 0. 18 0. 23 0. 26 MAY JUN 0. 78 0. 45 0.23 AUG 0. 93 0.47 0.99 OCT 0. 90 0. 20 0. 96  0. 81 0. 45 0. 68 1. 47 2. 39 2. 06  1. 90 1. 08 1. 11 2. 26 2. 54 1. 03  0. 0. 0. 0. 0. 0.  53 19 56 41 59 15  0.35 0.53 -0.53 1.06 0. 8 2 0.59  3.45 1.6 3 2.75 3.46 4.26 1.47  SUBALPINE RECLAIMED NF AUG 0. 56 0. 08 0. 49 OCT 0. 23 0. 19 0. 27 MAY 0. 12 0.21 0. 17 0.38 JUN 0. 32 0. 40 AUG 0. 21 0. 27 0. 43 OCT 0. 27 0. 13 0.26  1. 13 0. 69 0. 50 1 .10 0. 95 0. 66  1. 59 1.29 0. 64 1. 05 1. 06 0. 60  0. 11 0.31 0. 09 0. 26 0. 08 0. 03  1. 27 0.38 0. 3 8 0.29 0.83 0.51  1.91 2.20 0.90 1.81 1.29 0.69  133  POTASSIUM (G M**-2) MONTANE NATIVE F X 39. 48 41.34 52.05 67. 48 66. 88 50. 08  90f. CONFIDENCE LIMITS LOWER SX UPP ER 4. 98 24.94 54. 02 35.79 1. 90 46. 89 8. 59 26. 97 77. 13 107. 16 1 3. 59 27.80 4. 77 5 2.95 80. 81 25.79 74. 37 3. 32  MONTANE NATIVE NF 5. 64 1. 60 2. 42 9. 66 AUG 0. 65 2.49 5. 0 1 OCT 1 .36 4. 16 1. 23 1. 47 1. 46 MAY JUN 3. 89 0. 90 5. 44 10. 23 4. 86 9. 25 AUG 2. 36 1.53 1.77 1.09 5. 97 OCT 3. 12  39. 43. 34. 36. 46. 52.  56 18 41 18 05 53  1. 93 4. 53 5. 27 1 2. 71 7. 99 1 1. 40  MONTANE RECLAIMEDi Fl 1. 08 AUG 2. 53 0.64 OCT 3. 14 0. 67 0. 2 3 1.79 0. 36 0. 84 MAY 4. 16 0.71 JUN 2. 09 1. 44 0. 55 1. 09 AUG 3. 27 0.45 0. 65 OCT  4. 24 4. 05 2. 99 6. 96 3. 08 4. 37  7.36 5. 41 10. 35 9. 84 18. 75 7. 84  MONTANE RECLAIMEDi NF AUG 2. 42 0.49 0. 69 OCT 2. 90 1 . 26 0. 34 1. 76 0.58 MAY 0. 52 JUN 3. 76 0. 44 2. 12 1.08 0. 54 1. 38 AUG 0. 94 OCT 1.6 3 0.48  3. 61 4. 50 2, 37 6. 33 3. 01 3. 05  7. 19 8. 06 9. 17 6.32 9. 97 5.60  AUG OCT MAY JUN AUG OCT  DETSHOOT+RITUS+ROOT=TOTAL 5. 37 1 .05 2. 0 1 8. 43 1. 05 1. 21 1. 69 3. 95 1. 52 1.03 1. 39 3. 95 8.01 0. 80 3. 86 12. 67 8. 32 4. 11 0.98 3. 23 1. 44 0.57 1. 71 3. 72  SOIL  33.92 29.95 19.02 -0.93 22.72 19.24  45. 20 56. 41 49. 80 73. 29 69. 38 85. 82  1. 35 0. 64 1. 60 2. 49 1. 68 1. 15  3.42 3.54 5.68 2.57 13.84 4. 48  11. 30 7. 28 15. 02 17. 1 1 23. 66 1 1.20  1.91 1. 68 1. 47 1. 32 1. 61 0. 82  1.61 3. 15 4. 88 2.47 5.27 3.21  12.77 12. 97 1 3.46 10. 17 14. 67 7. 99  134  POTASSIUM (G M**-2) SUBALPINE NATIVE F  AUG OCT MAY JUN AUG OCT  DETSHOOT+RITUS+ROOT=TOTAL 1.88 0.91 1. 25 4. 04 0.49 1.21 0. 87 2. 56 1. 05 0. 99 3.31 5. 35 2. 72 1. 85 4. 14 8. 71 2. 53 0. 87 6. 94 3. 53 1. 43 0. 73 1. 23 3. 39  SUBALPINE NATIVE NF AUG 2. 08 1. 10 T. 67 OCT 0. 74 1 . 12 0.92 MAY 1.26 0. 98 2. 29 JUN 3. 23 0. 47 5. 17 AUG 1. 64 0. 89 3. 10 OCT 0. 25 0.60 1.55  SOIL  X 37.69 24. 83 36. 51 43.78 49. 00 32. 75  SX 6. 20 4.71 2.38 15. 21 4. 81 8.24  90% CONFIDENCE LIMITS LOSER UPPER 19.59 55.79 1 1.08 38. 58 2 9.56 43.46 -0.63 88. 19 34. 95 6 3.05 8.6 9 56.81  4. 85 2. 78 4. 52 8. 87 5. 63 2. 39  29. 50 25.61 33. 43 45. 15 49. 46 22. 88  5. 46 6.33 8. 05 7. 5 3 4.36 1. 18  1 3. 56 7. 13 9.92 23. 16 36.73 19.43  45.44 44.09 56. 94 67.14 62.19 26.33  SUBALPINE RECLAIMED F AUG 4. 80 0.09 0. 19 5. 08 OCT 2. 99 1 . 64 0. 30 4. 92 MAY 0. 86 0. 25 0. 39 1. 50 JUN 6. 12 0. 33 1.21 8. 17 AUG 11.48 0. 90 0.72 13. 11 OCT 7. 82 0. 75 0.91 9. 48  5.64 4. 12 12. 35 7.50 6.78 4.68  0. 70 0. 40 2.20 0. 66 0. 51 0.81  3.60 2. 95 5. 93 5.57 5.29 2. 31  7.68 5.29 18.77 9.43 8.27 7.05  4. 96 4. 24 4. 84 5. 13 5. 38 3.79  0. 77 0. 56 0. 42 0. 84 0. 32 0. 36  2.71 2. 60 3. 61 2. 68 4.45 2.74  7.21 5.88 6.07 7.58 6.31 4.84  SUBALPINE RECLAIMED NF AUG 0. 07 3. 19 0. 15 OCT 2. 22 1.18 0. 20 MAY 0. 80 0. 47 0.24 JUN 3.43 0. 72 0.73 AUG 2. 08 0. 39 0.87 OCT 1. 16 0.60 0. 56  3. 41 3. 61 1. 51 4. 88 3. 34 2. 33  135  CALCIUM {G M**-2) MONTANE NATIVE F  AUG OCT MAY JUN AUG OCT  DETSHOOT+RITUS+ROOT=TOTAL 6. 66 6.2 3 18.84 31. 74 0. 63 3.72 11. 00 15. 35 0. 23 5.4 3 8. 27 13. 93 1. 32 6. 42 33.46 41 .20 1. 50 6. 43 22. 1 4 30. 06 0. 56 4. 05 1 3. 85 18. 47  MONTANE NATIVE NF 3. 26 6. 22 17. 13 AUG OCT 0. 39 4.69 13.77 0. 22 12. 63 11.06 MAY JUN 0. 72 5. 62 35.65 1. 54 4. 54 36. 68 AUG 0. 18 6. 79 12. 19 OCT  26. 62 18. 85 23. 91 42. 00 42. 76 19. 15  90% CONFIDENCE LIMITS SX LOWER UPPER 96. 32 42 1. 24 983. 74 60. 22 482. 79 834.47 884. 84 37. 80 664.08 64. 39 58 5. 4 4 96 1.48 11 2. 12 387.24 1042. 02 76. 87 55 3. 25 100 2. 17  SOIL X 702.49 658.63 774. 46 77 3. 46 714.63 777.71  586.82 960.97 673.33 628.31 6 57.25 700. 90  34. 00 3 0, 79 58. 46 8. 46 47. 18 34. 37  487. 54 686. 10 87 1.06 1050. 88 502.63 844. 03 603.61 653. 01 51 9.48 795. 02 600. 54 80 1.26  MONTANE RECLAIMED F AUG 2. 80 3. 91 1.88 0. 49 OCT 1. 82 1.68 1. 10 3. 53 1. 33 MAY JUN 2. 85 3. 28 3. 26 1. 97 4.22 1.92 AUG 1.27 0.86 1.75 OCT  8. 59 3. 98 5. 97 9. 39 8. 10 3. 88  201.06 245.93 209.27 186.91 253. 43 312.38  2. 01 195. 19 42. 52 121.82 20. 89 148.27 8 1. 29 36. 17 2 9. 97 165.92 35.70 208. 14  206. 93 37C. 14 270. 27 292. 53 340. 94 416. 62  MONTANE RECLAIMED NF AUG 2. 74 3. 19 0.88 1.16 2. 88 0. 49 OCT 0. 59 6. 48 0. 96 MAY JUN 2. 91 3. 30 3. 31 1. 44 1. 20 6. 85 AUG 3. 20 1.78 OCT 0.65  6. 80 4. 53 8. 03 9. 52 9. 49 5. 63  375.32 414.79 308.31 3 95.90 417.93 428.64  51. 46 28. 01 2 4. 90 33. 96 17.75 36. 16  225.06 333.00 235.60 296.74 366. 10 323.05  525. 58 496. 58 381. 02 495. 06 469. 76 534. 23  136  CALCIUM (G M**-2) SUBALPINE NATIVE F 90%  AUG OCT MAY JUN AUG OCT  DETSHOOT+RITUS+ROOT= TOTAL 1. 46 5. 41 1 5. 70 22. 57 0. 43 4. 30 5.60 10.32 0. 25 9. 14 52. 27 61. 66 4. 41 51.34 56. 36 0.61 1. 74 4. 95 49.77 56. 45 0. 87 2. 43 13. 90 17.21  _ SOIL _ X SX 765.04 66. 70 577.85 115. 16 761.94 3 8. 12 684.46 45. 40 764.84 51. 03 634. 11 12 4. 35  CONFIDENCE LIMITS LOSER UPPER 570. 28 95 9.80 241.58 914.12 650. 63 873.25 55 1. 39 817.03 615.83 913.85 27 1.0 1 997.21  SUBALPINE NATIVE NF AUG 1. 51 7. 26 14.63 23. 40 734. 77 OCT 0. 88 5. 34 6.35 12. 56 641.60 MAY 0. 41 1. 81 20.75 22. 96 522.43 JUN 0.69 2. 90 51. 35 54. 95 591.91 AUG 0. 92 6. 56 3 1. 48 38. 96 726. 25 OCT 0. 28 3. 19 14.98 18. 46 61 1.79  26. 58 657. 16 108. 33 325.28 41.93 399.99 82. 45 351. 16 38. 71 61 3.23 53. 65 455. 13  SUBALPINE RECLAIMEDi F 1. 55 0.42 AUG 0. 34 OCT 0. 59 0. 92 0. 52 MAY 0. 10 1. 42 1. 02 JUN 0. 51 1.39 2. 80 1. 20 1.84 AUG 3. 6 1 OCT 1. 07 0.69 4. 74  2. 31 1247.63 2. 03 1016.98 2. 53 1119.57 4. 69 968. 63 6. 64 942.29 6. 50 715.54  56. 50 1082.65 1412.61 54. 43 858.04 1175.92 83. 51 37 5.72 1363.42 30. 85 878.60 1058.76 91. 35 675.55 1 20 9. 0 3 279. 39 - 100.28 1531.36  SUBALPINE RECLAIMED NF AUG 0. 31 0. 93 0. 32 OCT 0. 52 0. 69 0. 39 MAY 0.09 0. 91 0. 63 JUN 0. 47 1 .62 1. 13 AUG 0. 30 2. 02 1. 53 0.37 OCT 3. 27 1 .26  1. 56 1046.60 855. 14 1. 60 1. 63 846.73 3. 22 731.24 4. 36 725.38 4. 90 714.04  177.22 149. 95 1 1 8.94 239. 27 5 1. 55 33.09  529.12 417.29 499.43 3 2.57 57 4. 85 617.42  812.38 957.92 644.87 832.66 839.29 768.45  1564. 08 1292.99 1194.03 1429.91 87 5.91 810.66  137  MAGNESIUM (G M**-2) MONTANE NATIVE F  AUG OCT MAY JUN AUG OCT  DETSHOOT+RITUS+ROOT=TOTAL 0.54 0.68 2. 32 3. 53 0. 11 0.45 1.69 2. 25 0. 1 1 0.71 1. 26 2. 08 0. 47 0. 56 4. 25 5. 27 0. 37 0.78 4. 23 3.09 0. 20 0. 39 1.51 2. 10  SOIL  X 6 3.33 57. 38 65. 40 74. 59 56.26 75. 10  SX 15.51 1. 31 5. 15 7. 21 8. 66 1 1. 64  MONTANE NATIVE NF AUG 0.64 0.71 2. 42 OCT 0. 08 . 0.55 1. 98 MAY 0. 09 0.99 1.37 JUN 0. 25 0.63 4. 20 AUG 0. 33 0. 66 3. 86 OCT 0. 06 0. 74 1.67  3. 78 2. 61 2. 45 5. 08 4. 84 2. 47  52. 49 94. 12 77. 23 59.09 71.28 64.51  6.72 9. 50 16. 73 5. 33 12. 02 6. 84  MONTANE RECLAIMEDi F AUG 0. 69 0.61 0.59 OCT 0.51 0.39 0.05 MAY 0. 32 0.33 0.50 JUN 0. 55 0. 37 0.73 AUG 0. 28 0.49 0.54 OCT 0. 28 0. 21 0.31  1. 89 0. 94 1. 14 1. 65 1. 32 0. 80  24. 18 31. 16 25. 57 23. 59 29.17 42. 19  MONTANE RECLAIMED NF AUG 0. 86 0. 56 0. 37 OCT 0. 46 0. 65 0. 14 MAY 0. 27 0.73 0. 34 JUN 0. 65 0.39 0. 74 AUG 0. 29 0.31 1. 10 OCT 0. 20 0.51 0.48  1. 78 1. 26 1. 34 1. 78 1. 70 1. 20  55. 96 58. 82 42.76 67. 04 67. 20 66. 42  90^ CONFIDENCE LIMITS LOWER UPPER 2 3.04 113. 62 53.55 6 1.21 50.36 80. 44 53. 54 95. 64 30.97 3 1.55 41.11 10 9.09  32.87 66.38 2 3.38 43.53 36.18 44.54  72. 1 1 121. 86 126. 0 8 74. 65 106. 38 84. 48  1. 76 6. 85 3. 36 4.33 6. 03 8. 67  19.04 11.16 15.76 10.95 1 1. 56 16.87  29. 32 5 1.16 35. 38 36. 23 46. 78 67. 51  13. 05 6. 48 5.67 8.25 4. 12 6. 41  1 7. 85 39.90 26.20 42.95 55. 17 47.70  94. 07 77. 74 59.32 91. 13 79. 23 85. 14  138  MAGNESIUM (G M**-2) SUBALPINE NATIVE F  AUG OCT MAY JUN AUG OCT  DETSHOOT+BITUS+ROOT=TOTAL 0. 30 0.72 1. 99 3. 01 0. 09 0. 58 0. 82 1. 49 0. 09 0. 97 6.5 9 7. 65 0. 24 0. 55 5.72 6.51 0. 41 0. 58 5.6 0 6.59 0. 20 0.33 1.60 2. 12  SUBALPINE AUG 0. 32 OCT 0. 12 MAY 0. 11 JUN 0. 22 AUG 0. 24 OCT 0.05  NATIVE 0. 97 0. 70 0. 45 0. 37 0. 72 0. 40  NF 2. 18 3. 48 0. 85 1. 68 2. 64 3. 19 5.72 6.31 3. 98 4. 95 1. 52 1. 97  _ SOIL X SX 82. 65 3. 24 63. 86 1 0. 60 92. 79 0. 65 85. 13 9. 06 89. 40 1 1. 46 78.55 14.81  90%  CONFIDENCE LIMITS LOWEB UPPEH 73. 19 92. 1 1 32.91 94.81 90.89 94.69 58. 67 11 1.59 5 5.94 122. 86 35.30 12 1.80  76.33 67.51 57.93 70. 94 81. 70 58. 93  3. 52 7.50 6. 37 12. 52 8. 84 8. 04  SUBALPINE RECLAIMED F AUG 0.43 0.09 0.11 0.63 OCT 0. 24 0.31 0. 10 0. 66 MAY 0. 06 0.18 0. 26 0. 49 JUN 0. 36 0.41 0.65 1.41 AUG 0. 86 0.45 0. 90 2.22 OCT 0.59 0.21 1. 05 1. 85  33.62 27.20 27. 96 35. 87 32.71 26.78  2. 39 3.59 1. 84 2. 55 2. 22 0. 15  26.64 16.72 22.59 28.42 26.23 26.34  40.60 37.68 33.33 43.32 3 9.19 27.22  SUBALPINE RECLAIMED NF AUG 0. 27 0 .07 0. 10 0. 45 OCT 0.19 0.22 0.06 0.48 MAY 0.05 0.22 0.13 0. 46 JUN 0.21 0.34 0.21 0. 77 AUG 0. 24 0. 33 0.40 0. 97 OCT 0.15 0.31 0.62 1.08  37.25 30. 85 28. 10 30. 02 29. 78 23.69  5. 58 4. 15 2. 82 6. 04 3. 06 1. 36  20.96 18.73 1 9.87 12.38 20. 84 19.72  53.54 42.97 36.33 47.66 38.72 27.66  66.05 86.6 1 45.61 89.41 39.33 7 6.53 3 4. 3 8 107.50 55.89 107.51 3 5.45 82.41  1  139  Appendix II.  Net change i n Ca and Mg mass (g m ) between sampling dates i n the s h o o t , d e t r i t u s , r o o t and s o i l compartments, the s o i l data r e p r e s e n t exchangeable l e v e l s .  140  MONTANE AUG-OCT OCT-MAY MAY-JUN JUN-AUG AUG-OCT  CALCIUM  M**-2)  SHOOT  DETRITUS  -6.03 - o . ao 1.09 0.18 -o.9a  -2. 1. 0. 0. -2.  51 71 99 01 38  ROOT -7.8a -2.73 25.19 -11 . 3 2 -8.29  TOTAL -16.39 -1.42 27.27 -11.14 -11.59  SOIL -43.86 115.83 -1 . C O -58.83 63 , C 8  0 . 33  2 .85  3 . 12  1 19.08  - 1 . 53 7 . 94 -7. 01 - 1 . 08 2. 25  -3.36 -2.71 24.59 1.03 •24.49  -7.77 5.06 18.09 0.76 -23.61  374 . 1 5 -287.64 -45.02 28.94 43.65  2. 10  -1.58  0.30  -260.07  23 85 25 94 47  -1.39 0.84 1.93 -1 . 3 4 -0.65  -4.61 1.99 3.42 -1.29 -4.22  44.92 -36.71 -22.36 66.52 56.95  0 . 07  0.78  - 0 . 10  6 6 . 40  31 60 18 10 00  -0.39 0.47 2.35 3.54 -5.07  -2.27 3.50 1 .49 -0.03 -3.86  39.47 -106.48 87.59 22.03 10.71  0 . 32  1 .29  1. 10  1 3 . 85  NATIVE  P  NET (OCT--OCT) - 0 . 07  MONTANE AUG-OCT OCT-MAY MAY-JUN JUN-AUG AUG-OCT  N A T I V E NF - 2 . 87 - 0 . 17 0.50 0.82 -1.36  NET (OCT-•OCT) - 0 . 2 1  MONTANE AUG-OCT OCT-MAY MAY-JUN JUN-AUG AUG-OCT  RECLAIMED -0.98 -0.72 1.75 -0.88  F -2. 1. -0. 0. -2.  -1.11  N E T ( O C T - •OCT) - 0 . 9 6  MONTANE AUG-OCT OCT-MAY MAY-JUN JUN-AUG AUG-OCT  RECLAIMED -1.58 -0.57 2. 32 -1.47 -0.79  N E T ( O C T - OCT) - 0 . 5 1  NF -0. 3. -3. -2. 2.  141  SUBALPINE AUG-OCT OCT-MAY MAY-JUN JUN-AUG AUG-OCT  CALCIUM (G M**-2) NATIVE F SHOOT DETRITUS RCOT -1.03 -1.11 -10.10 -0. 18 4. 84 46.67 0.36 -4.73 -0.93 1.13 0. 54 -1 .57 -0. 87 -2.52 -35.87  NET(OCT-•OCT) 0. 44 SUE ALPINE AUG-OCT OCT-MAY MAY-JUN JUN-AUG AUG-OCT  -1.87  NATIVE NF -0.63 - 1 . 92 -0.47 -3.53 0.28 1.09 0.23 3. 66 -0.64 -3. 37  NET(OCT- OCT) -0.60  8.30  -8.28 14 .40 30.60 -19.87 -16.50  TOTAL - 12.25 51.34 -5.30 0.09 -39.24  S GIL -187.19 184.09 -77.48 80.38 -13C.73  6.89  56. 26  -10.84 10. 40 31.99 -15.99 -20.50  -93.17 -119. 17 69.48 134.35 -114.47  -2. 15  8.63  5.90  -29.81  SUBALPINE RECLAIMED F AUG-OCT -0.96 0.50 OCT-MAY -0.49 0.50 MAY-JUN 0.4 1 -0.03 JUN-AUG 0.69 0.45 AUG-OCT -0. 13 - 1 . 15  0.18 0.50 1.78 0.81 1.13  -0.28 0.50 2.16 1.95 -0.1 4  -230.65 102.59 -150.89 -26.39 -226 .75  NET(OCT- OCT) 0.48  4.22  4.47  -301.44  0.07 0.24 0.50 0.89 1.25  0.04 0.03 1.59 1. 14 0.54  -191.46 -8.41 -115.49 -5. 86 -11 .34  2.88  3.30  -141. 10  SUEALPINE AUG-OCT OCT-MAY MAY-JUN JUN-AUG AUG-OCT  -0.23  RECLAIMED NF -0.41 0.38 -0.43 0. 22 0.71 0. 38 0.33 -0. 09 -0.43 -0.27  NET(OCT- OCT) -0. 15  0.57  142  MAGNESIUM MONTANE NATIVE F SHOOT DETRITUS AUG-OCT -0.43 -0.23 OCT-MAY 0.0 0.26 MAY-JUN 0.36 -0.15 JUN-AUG -0.10 0.22 AUG-OCT -0.17 -0.39 NET (OCT-OCT)  0.0 9  MONTANE NATIVE NF AUG-OCT -0.56 OCT-MAY 0.01 MAY-JUN 0.16 JUN-AUG 0.08 AUG-OCT -0.27 NET (OCT-OCT) -0.0 2  ROOT -0.63 -0.43 2.99 -1.16 -1.58  TOTAL -1.28 -0.17 3.19 -1.04 -2.13  SOIL -10.95 8.02 9.19 -18.33 18.84  -0.06  -0.18  -0.15  17.72  -0.16 0.44 -0.36 0.03 0.08  -0.44 -0.61 2.83 -0.34 -2.19  -1.17 -0.16 2.63 -0.24 -2.37  41.63 -16.89 -18.14 12.19 -6.77  0.19  -0.31  -0.14  -29.61  -0.54 0.45 0.23 -0.19 -0.23  -0.95 0.20 0.5 1 -0.33 -0.52  6.98 -5.59 -1.98 5,58 13.02  0.26  -0.14  11 .03  -0.23 0.20 0.40 0.36 -0.62  -0.52 0.08 0.44 -0.08 -0.50  2. 86 -16 . G6 24.28 0. 16 -0.78  0.34  -0.06  MONTANE RECLAIMED F AUG-OCT -0.18 -0.22 GCT-MAY -0. 19 -0.06 MAY-JUN 0.23 0.04 JUN-AUG -0.27 0. 12 AUG-OCT 0.0 -0.28 NET(OCT-•OCT) -0.23  -0. 18  MONTANE RECLAIMED NF AUG-OCT -0.40 0.09 OCT-MAY -0. 19 0.08 MAY-JUN 0.38 -0.34 JUN-AUG -0.36 -0.08 AUG-OCT -0.0 9 0.20 SET(OCT- OCT) -0.26  (G M**-2)  -0.14  7.60  143  MAGNESIUM SUBALPINE NATIVE F SHOOT DETRITUS AUG-OCT -0.21 -0.14 OCT-MAY 0.0 0.39 MAY-JUN 0.15 -0.42 JUN-AUG 0.17 0.03 AUG-OCT -0.21 -0.25 NET(OCT-OCT) 0.11 SUBALPINE AUG-OCT OCT-MAY MAY-JUN JUN-AUG AOG-OCT  NATIVE NF -0.20 -0.27 -0.01 -0.25 0.11 -0.0 8 0.02 0. 35 -0.19 -0.32  NET(OCT-OCT) -0.07  AUG-OCT OCT-MAY MAY-JUN JUN-AUG AUG-OCT  -0.25  -0. 30  (G M**-2) ROOT -1.17 5.77 -0.87 -0.12 -4.00  TOTAL -1.52 6.16 -1.14 0.08 -4.47  SOIL -18.79 28.93 -7.66 4.27  0.78  0.63  14.69  -1.33 1 .79 3.08 -1 .74 -2.46  -1.80 1.51 3.12 -1.36 -2.98  -8.82 -9.58 13,01 10.76 -22.77  0.67  0.29  -8.58  10.85  F  -0.19 -0.18 0.30 0.50 -0.27  0.22 -0. 13 0.23 0.04 -0.24  -0.01 0.16 0.39 0.25 0.15  0.03 -0. 17 0.92 0.81 -0.37  -6.42 0.76 7.91 -3. 16 - 5 . S3  NET(OCT-OCT) 0. 35  -0. 10  0.95  1.19  - 0 . 42  0.15 0.0 0. 12 -0.0 1 -0.02  -0.04 0.12 0.03 0.19 0.22  0.03 -0.02 0.31 0.20 0.1 1  -6.40 -2.75 1.92 -0.24 -6 .09  0. 09  0.56  0.60  -7. 16  AUG-OCT OCT-MAY MAY-JUN JUN-AUG AUG-OCT  -0.08 -0. 14 0. 16 0.03 -0.09  NET(OCT-OCT) -0. 04  144  Appendix III.  P r e c i p i t a t i o n data (cm rLO) over the study period measured at the v a l l e y bottom (Natal) and the ridge top (Harmer). These data represent the range of p r e c i p i t a t i o n regiernes found within the study area. The hatchures represent p r e c i p i t a t i o n f a l l i n g as rain and the white as that f r a c t i o n of t o t a l p r e c i p i t a t i o n which f e l l as snow.  145  146  J F M A M J  J A S  1976  '  O N D J  F M A M J J A S O N 1977  147  Appendix IV.  P r e c i p i t a t i o n which f e l l as rain or snow during the study period as well as average maximum and minimum a i r temperatures. The Natal and Harmer stations were at 1030 and 2100 m ASL respectively.  148  Month  Rain (cm E 0) o  Snow (cm HoO)  Total.  rT.emp(s r a t u r . e X i-i i n X Hax..  N a t a l 1976J  0.20  6.15  F  0.03  M i\ ±s.  -0.6  -1Q..0  6.43  6.35 6.4-6  0.  -7.3  2.46  1.65  4-. 06  1.7  -8.9  1.30  0.20  1.50  -1.1  M  6 ..86  0  6.86  11.7 17.2  J  3.05  0  3-05  17.8  3-3  J  3.56  0.  3 • 56  23.3  7-2  A.  16.51  0  16.51  21.7  7.8  o  1.25  0  1.25  21.1  0  3-30  0.20  3-50  11.7  3.3 -1. L  N  2.21  1.57  3.81  3.9  -6.7  D  1.37  0.81  2 ..18  2.2  -7-2  Total.  4-2.16  17.02  59.18  -4.X7  -12.50  1.7  Natal. 1977 J  1.09  1.4-0  2.4-9  j?  Q.ia  0.-30  0...48  3-78  -6.33  2.77 0  3.30  4.21  A  0.53 1.63  1.63  14.50  -5.95 -2.76  M  3.01  0  3.01  ,14.28  3.33.  J  4.65  0.  4.65  23-78  J  2.69  0  2.69  23-37  5.17 ' 6.36  xi.  11.30  0.  11-30  23.35  5.67  S>  5.4-1  0  5.41  15-39  2.48  0.  3.73  0.06  3.81.  11.-94  -2.74  N  2.36  2.18  4.55  0.1-7  -9.67  H  149  Month.  Rain (cm EUO)  Snov; (cm IlpO)  Total.  _Temp e r a t u r e . X' Max X Min  Harmer. 1976 J  0.  11.05  F  o..  M  -3-5 -5.0  -12.0  16.51  11.05 16.51  0  7.62  7.62  0  M  0^0.8  1.17 3.10  1.17 3-18  -4.5 5.0  -12.0  ii. -  9.5  -0.5  J  2.21  0.74  2.95  10.5  J  4.-57  0  4-, 57 •  18.0  1.5 7.0  A i i  31.50  .  o.  16.0  1..61  1.5.0 .0.5 0  -1.5 -7.0  -4.5.  -10.0  1.25 0  a. 51  2.82  N  0.71 ' 0  3-05  3-33 3.76  5.92  5.92  52.3^  9.3.17.  Total..  40.33  -4..0  31.50  0.36 •  D  -12...0  5-5 5.0  Earmer 1 9 7 7 J  0,  3.66  3.65  -8.17  -14.91  E  0  3 . .81  3.-81.  0,  9.52,  9.52  -1.37 -1.68  -8.91  M A  1.-.0.7  1.40  2.47  6.57  -4.47  M  1.42  5.00.  6.42  -2.04  J  2.08  0.38  2.46  7.^9 I6.15  J  3.25 8.26  0.51  3.76  16.92  4.27  17-24  4.64  A_ S 0 T-.T  11  D  10.16  a. 1 3 0  0.18  -  8.-44  -11..09  4.24  1.35  II..5I.  9.56  0.24  2.79  2.92.  5.18  -4.23  8.89  8.89  -4.83  -11.78  150  Appendix V.  Mean monthly temperatures at Natal (1030 M ASL) and Harmer (2100 m ASL) from 1973.to 1977.  MEAN MONTHLY TEMPERATURE - NATAL 70 •  ! ITTI.T ; ! : ! I I I I !. ! ] 1  1  1  R  I ;  1  :  i i  ST t I  i  1  i  !I II ] i ! |  i i i : i  I I M 'I "I I . i III I |l ! 60' I i 'l i I i l M i" I i i iMiii ri ' I'l'ITi ' I ! I ! i I ! '! I T i |T  i i •i . ' ' 'r rrn i r r r I "r i T T ! r i TTirr I  50'J  |  :i; : :..L r|  ,  '.T ! i r r n t i r t i i rrii !I r rTIT'Tl i r I rri r i i i i i • 'I I I I T ! i i n H i"! I : ri "i I T T IT I T T T ' i ! I"IT r t t h . 1  n  1  1  40' •  i ri r r r '  ""  i ITTTT  'Vi n i i :i i i ii i i i rri r IT i i r n rr""' i i n i rr i r IT n r r r n i ITT r; i i I i r n , i' IT I I I' rrr i r n IT : rt i i ri r r n 3 0  1 T T Ii i !I Vf IT I ! i i ! ri IT"]'" ! M !I I rri! r n  Month  153  Appendix VI.  Monthly snowfall at Natal (1030 m ASL) and Harmer (2100 m ASL) from 1973 to 1977.  wa.tci ( x 10= 4now)  •<0WrH/./ SNOWFALL - hi AT A L  M  .1  ^rrrrJJ^n LU.TJ i "u "j .1 i.i , , ! U  Month  0  Q  > MONTHLV SNOWFALL - WARMER  V  Mill  LU. !  i  I i T r n I I.I I.I.I ! i s  ' < 1  i I i i i s i I i i..i M M . " M I I I i Ii , I || | | O N  . ••  !  S  . I I . II I I i I i II I I M Ii I  i i  r rI I I"I i || | |i (  I  .I  !  156  Appendix VII.  Net change in oven dry organic matter (g rn" day" ) between sampling dates f o r the shoot, d e t r i t u s and root compartments. 2  1  shoot  d e t r i tus  root  •total  Montane native F Aug/Oct  -4.33  -5.12  -8.25  -17.70  Oct/May  -0.07  1.74  -0.96  0.71  May/June  5.51  -7.63  68.02  65.90  June/Aug  0.13  3.36  -18.61  -15.12  Aug/Oct  -2.49  -5.45  -13.93  -21.88  Montane native NF Aug/Oct  -5.66  -6.61  -8.30  -20.57  Oct/May  0.01  2.74  -1.13  1.63  May/June  3.11  -13.05  57.41  47.46  June/Aug  0.26  2.03  -6.61  -4.32  -2.25  -2.02  -20.33  -24.60  Aug/Oct  Montane reclaimed F Aug/Oct  -0.49  -3.03  -7.40  -10.92  Oct/May  -0.37  0.82  1.93  2.38  May/June  2.69  0.12  3.47  6.27  June/Aug  -1.83  -0.10  0.48  -1.46  Aug/Oct  0.74  -2.32  -4.39  -5.96  Montane reclaimed NF Aug/Oct  -0.73  -1.28  -5.49  -7.50  Oct/May  -0.38  0.69  1.13  1.43  May/June  2.93  -3.65  7.39  6.13  June/Aug  -1.46  0.79  2.12  1.45  Aug/Oct  -0.26  -1.80  -3.71  -5.77  158  shoot  d e t r i tus  root  total  Subalpine native F Aug/Oct  -2.62  0.78  -12.94  -14.79  Oct/May  0.04  1.22  13.16  14.43  May/June  2.84  -9.47  8.33  1.69  June/Aug  0.91  -0.51  -10.23  -9.83  Aug/Oct  -1.43  -3.21  -31.73  -36.37  Subalpine native NF Aug/Oct  -1.48  -3.04  -11.40  -15.91  Oct/May  -0.06  0.08  5.59  5.61  May/June  2.25  -4.85  48.60  46.00  June/Aug  -0.56  4.18  -21.66  -18.03  Aug/Oct  -1.54  -3.97  -21.45  -26.96  Subalpine reclaimed F Aug/Oct  -2.70  2.65  0.40  0.35  Oct/May  -0.53  0.05  0.59  0.11  May/June  3.95  3.27  4.12  11.34  June/Aug  5.36  -0.14  4.55  9.77  Aug/Oct  -1.02  -2.30  -1.54  -4.86  Subalpine reclaimed NF Aug/Oct  -1.20  1.89  0.37  1.06  Oct/May  -0.49  0.36  0.38  0.25  May/June  2.74  2.78.  3.34  8.95  June/Aug  -0.25  -1.38  2.19  0.56  Aug/Oct  -0.32  0.30  -1.88  -1.89  159  Appendix VIII.  Nutrient concentrations in the shoot, root and d e t r i t u s compartments throughout the study.  160  Nitrogen Concentration Shoot  F  Detritus  NF  F  1.24 1.01  1.05 1.32 1.46  NF  (%) F  Root NF  Montane N a t i v e Aug Oct May June Aug Oct  1.25  1.15 2.15 2 . 27  2.29 1. 85  1.22 0.91 1.58  1.19 0. 52 1.77 2.44 1.71  0.95 0.93 1.02 1.15 1.10 1.22  0.44 0.84 1.06 1.45 1.06 1.17  1.40  1.69 1.43  1.66 1.36 1.33 1.46  1.40 1.60  1.31 1.10  1.94 0.53  3.08 2.35  2.75 2.13  1.38 1.42 1.31 1.73 2.19 2.02  1.77  1.71  1.81  1.50  1.33  1.67 1. 31 1.21 1.54 1.60  1.10 2.02  1.92 1.25  2.02 1.53 1. 42 1.46 1.46  1.88  Montane R e c l a i m e d Aug Oct May Jun Aug Oct  3.29  2.81  Subalpine Aug Oct May Jun Aug Oct  Aug Oct May Jun Aug Oct  2.25  1.81  Native  1.22 1.20 2.21 2. 71 1.96 2.73  Subalpine  2.92  1.20 0.'8l 2.00 1.65  1.13 1.30  1.47 0 .76 1.42 1.68 1.23 1.69  0.89  0.63 1.10 1. 22 1.10  1.65  1.54 1.73 2.04  . 1.50  0.63 0.45 0.79 0 .86 0.77 0.76  0. 74 0.44 0.58 0.51 0.62 0 .71  1.52  Reclaimed  1.15 0.78 1.65  3.79 2.08 1. 28  1.18 0.65 1.60  1.46 0.94 0.76  1.25  0.02 1.17 0.85 1.08 1.12  1. 21 0.46 0.79  0.77  0.73 0.69  161  Phosphorus Shoot • NF  F  Concentration F  Detritus  (%)  NF  F  Root'  NF  Montane N a t i v e Aug Oct May Jun Aug Oct  0.20 0 .40 0 . 34  0.40  0 .26 o .22  0.21 0.36 0 . 32 0 . 32 0 . 22 0.39  '  0 0 0 0 0 0  .16 .19 .21  0 0 0 0 0 0  .13 • 32 .15 .16 .25 .26  0 0 0 0 0 0  .12 .31 .13 .11 .15 .13  0 0 0 0 0 0  .15 .34  .14  .11 .28 .13 . 21 .13 .18  Montane R e c l a i m e d Aug Oct May Jun Aug Oct  0.18 0 .35 0.37 0.30 Q.23 0.38  Subalpine Aug Oct May Jun Aug Oct  Aug Oct May Jun Aug Oct  0 0 0 0 0 0  .13 .25 .15 .31 .26 .21  0 0 0 0 0 0  .13 .35 .29 .22 .16 .37  0 0 0 0 0 0  .15 .'52 .15 . 12 .19 .19  0 0 0 0 0 0  0.21 0.26 0.32 0 . 32 0.23  0 0 0 0 0 0  .15 .18 .13 .23 .17 .20  0 0 0 0 0 0  .15 .22 .08  .14 .14 .14  0 0 0 0 0 0  .12 .12 .15  . 20 . 20  0 0 0 0 0 0  .12 .26 .11 .13 .13 .16  0 0 0 0 0 0  .29 .13 .10 .10 .11 .10  0 0 0 0 0 0  .12 .09 .11 .06 .16 .19  0 0 0 0 0 0  .57 .25 .09 .13 .12 .09  .10  .41 .14 .12 .20 .17  Native  0 .19 0.27 0 . 30 0.38 0.27 0 . 34  Subalpine  0.19 0.37 0.33 0.29 0.20 0.29  0.24  .14  Reclaimed  0 .21 0 .16  0.42  0.43 0 .21 0 .23  0 . 27 0 .17 0 . 31 0.28 0.17 0.13  0 .17 0 .06 0 .12 0. .14 0 .16 0 .13  '  •  162  Potassium Shoot  F  NF  Concentration F  Detritus  NF  (%) F  .Root NF  Montane N a t i v e Aug Oct May Jun Aug Oct  1. 50 1.02 1.73 2.85 1.43 1.10  1.40 0.95 1.73 2.16 1.48 2.13  0.14 0 . 27 0 .13 0.15 0 .14 0.16  1.16 1.75 2.02 2. 20 1.09 1.96  0 .21 0 . 54 0.12 0 .24 0 .19  1.16 0.84 1.66 2.09  0 .19 0 .23 0.13 0.42 0.21 0 .34  0.17 0.24 0.20 • 0 .15 0.17 0.22  0.23 0. 89  0.23  0.18  0.13  0.14 0.15 0.15  0 . 50 0.14 0 .15 0 .22 0 . 31  0.16 0 .16  0.16  0. 20 0 .23 0 .17 0.34 0.17 0 .18  0.15 0 .25 0.14 0 . 34 0 .19 0 .19  0.10  0.13 0.15 0 .13 0 .15 0 .13 0 .15  0.12 0 .14 0.12  0.18 0 .18  0 .22  Montane R e c l a i m e d Aug' Oct May Jun Aug Oct  1.31 1.92  2.04 2.29  1.57 2.36  Subalpine Aug Oct May Jun Aug Oct  Aug Oct May Jun Aug Oct  0.18  0 .19 0.28  Native  0. 89 0.86 1.60  1.65 1. 21 1.20  Subalpine  0.31  0.54 0 .16  1.29 0.82  0.18  0 .10 0.12 0 .12 0 .13  Reclaimed  1.55 1.99 2.03 3.39 2.59 1.97  1.54 1.63 2.15 2.58 1. 72 1.15  0.13 0 .27 0 .30 0.48  0.84 0.22 0.23 0 .16 0.23  0.21 0.26 0.17 0 . 32 0 .12 0.18  0.18  0 .19 0.13 0.24 0 .21 0 .19  

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