A three-dimensional spatial model for plant competition in an heterogeneous soil environment

Abstract The model described in this paper, the three-dimensional model for the interaction of plants and soil (3DMIPS), was developed to explore how the growth and competitive ability of plants is affected by the interactions between the size and scaling properties of their root systems and the spatial properties of the resources they consume. The main characteristics of the model are as follows. (1) The soil model simulates the spatiotemporal dynamics of temperature, water and solutes (nutrients) in a heterogeneous, 3-dimensional (3-D) soil profile. (2) The plant model has a 3-D simulation of root architecture and plasticity (the ability of certain plants to redirect root growth to areas with high soil nutrient concentration). Plant root architecture is a key component in the simulation of plant nutrient uptake and transpiration. (3) The model simulates the spatiotemporal dynamics of live root, dead root, live shoot, standing dead, and litter biomass and nutrients of individual plants. It simulates the translocation of biomass and nutrients between roots and shoots as a function of plant growth, nutrient uptake, defoliation, regrowth, senescence, and changes in environmental condition. The author presents two set of simulation results. The first set consist of model validation experiments where the author compares model results with data from experiments designed to test the model's ability to predict plant growth and competition in a heterogeneous soil nutrient environment. Model and experimental results were statistically similar in 297 of the 408 variables analyzed. Experimental and modeled variables that were statistically different, were nevertheless highly correlated, with the difference between model and experimental results averaging ±28%. The second set of simulations was designed to assess how plant growth can be affected by an interaction between root lateral spread and the supply rate and spatial distribution of soil nutrients. Results showed that the competitive ability, distribution, and performance of plants could be linked in part to interactions among the size, uptake rates, and scaling properties of their root systems and the supply rate and spatial distribution of the nutrients they utilize. Comparisons are made with the SPUR, PHOENIX, CENTURY, and GEM grassland models. Computer codes and instructions for the implementation of 3DMIPS are available from the author.

[1]  D. Tarzia,et al.  ON THE FREE BOUNDARY PROBLEM FOR THE MICHAELIS‐MENTEN ABSORPTION MODEL FOR ROOT GROWTH , 1990 .

[2]  M. Noordwijk,et al.  MASS FLOW AND DIFFUSION OF NUTRIENTS TO A ROOT WITH CONSTANT OR ZERO‐SINK UPTAKE II. ZERO‐SINK UPTAKE , 1994 .

[3]  H. Reisenauer,et al.  Plant nitrogen fractions as indicators of growth rate , 1985 .

[4]  G. Ågren,et al.  The relationship between the growth rate of young plants and their total-N concentration is unique and simple: a comment , 1995 .

[5]  Theodore C. Hsiao,et al.  Simulation of soil temperature in crops , 1992 .

[6]  William H. Press,et al.  The Art of Scientific Computing Second Edition , 1998 .

[7]  F. Chapin,et al.  A model of nitrogen uptake by Eriophorum vaginatum roots in the field: Ecological implications , 1997 .

[8]  H. Lambers,et al.  Carbon and nitrogen economy of 24 wild species differing in relative growth rate. , 1990, Plant physiology.

[9]  Per Moldrup,et al.  Solute Diffusion and Adsorption in Six Soils along a Soil Texture Gradient , 1999 .

[10]  M. Palmer,et al.  The Coexistence of Species in Fractal Landscapes , 1992, The American Naturalist.

[11]  P. Keddy,et al.  Root and shoot competition intensity along a soil depth gradient , 1995 .

[12]  R. Brown,et al.  A Difference in N Use Efficiency in C3 and C4 Plants and its Implications in Adaptation and Evolution1 , 1978 .

[13]  Robert B. Jackson,et al.  PLANT COMPETITION UNDERGROUND , 1997 .

[14]  W. Parton,et al.  Analysis of factors controlling soil organic matter levels in Great Plains grasslands , 1987 .

[15]  D. Tilman.  Resource competition and community structure. , 1983, Monographs in population biology.

[16]  G. Campbell,et al.  The Effects of Texture on the Resistance to Water Movement within the Rhizosphere , 1984 .

[17]  D. Tilman.  Constraints and tradeoffs: toward a predictive theory of competition and succession , 1990 .

[18]  G. Ågren,et al.  The Influence of Plant Nutrition on Biomass Allocation. , 1991, Ecological applications : a publication of the Ecological Society of America.

[19]  Donald A. Klein,et al.  Simulation model for the effects of climate change on temperate grassland ecosystems , 1991 .

[20]  L. Pan,et al.  Improving Numerical Modeling of Two-Dimensional Water Flow in Variably Saturated, Heterogenous Porous Media , 1997 .

[21]  Erkki Aura.  Modelling non-uniform soil water uptake by a single plant root , 1996 .

[22]  François Tardieu,et al.  Modeling Root Water Potential and Soil‐Root Water Transport: II. Field Comparisons , 1991 .

[23]  W. Parton,et al.  A multi-species model for rangeland plant communities , 1988 .

[24]  Allocation of carbon and nitrogen as a function of the internal nitrogen status of a plant: Modelling allocation under non-steady-state situations , 1993 .

[25]  F. Tardieu,et al.  Carbon nutrition, root branching and elongation: can the present state of knowledge allow a predictive approach at a whole-plant level? , 1993 .

[26]  P. J. Smethurst,et al.  SIMULATING NUTRIENT UPTAKE BY SINGLE OR COMPETING AND CONTRASTING ROOT SYSTEMS , 1993 .

[27]  M. van Noordwijk,et al.  MASS FLOW AND DIFFUSION OF NUTRIENTS TO A ROOT WITH CONSTANT OR ZERO-SINK UPTAKE II. ZERO-SINK UPTAKE , 1994 .

[28]  H. W. Hunt,et al.  Phoenix, a model of the dynamics of carbon and nitrogen in grassland soils , 1981 .

[29]  S. A. Barber,et al.  Simulation Model for Nutrient Uptake from Soil by a Growing Plant Root System1 , 1976 .

[30]  A. Fitter.  11 – Architecture and Biomass Allocation as Components of the Plastic Response of Root Systems to Soil Heterogeneity , 1994 .

[31]  F. A. Seiler,et al.  Numerical Recipes in C: The Art of Scientific Computing , 1989 .

[32]  M. Biondini,et al.  Effects of nitrogen fertilization in leafy spurge root architecture , 2000 .

[33]  François Tardieu,et al.  Modeling root water potential and soil-root water transport. I. Model presentation , 1991 .

[34]  J. H. Cushman.  An Analytical Solution to Solute Transport Near Root Surfaces for Low Initial Concentration: I. Equations Development1 , 1979 .

[35]  S. A. Barber,et al.  Sensitivity Analysis of Parameters Used in Simulating K Uptake with a Mechanistic Mathematical Model1 , 1983 .

[36]  J. P. Grime,et al.  Plant Strategies and Vegetation Processes. , 1980 .

[37]  W. D. Evans,et al.  PARTIAL DIFFERENTIAL EQUATIONS , 1941 .

[38]  J. H. Edwards,et al.  Phosphorus Uptake Rate of Soybean Roots as Influenced by Plant Age, Root Trimming, and Solution P Concentration1 , 1976 .

[39]  Aristotelis Mantoglou,et al.  A theoretical approach for modeling unsaturated flow in spatially variable soils: Effective flow models in finite domains and nonstationarity , 1992 .

[40]  Thomas J. Givnish,et al.  On the economy of plant form and function. , 1988 .

[41]  Gaylon S. Campbell,et al.  Soil physics with BASIC :transport models for soil-plant systems , 1985 .

[42]  Harold A. Mooney,et al.  Modelling optimal plant biomass partitioning , 1994 .

[43]  Don Kulasiri,et al.  A root-morphology based simulation for plant/soil microbial ecosystem modelling , 1997 .

[44]  Christopher B. Field,et al.  photosynthesis--nitrogen relationship in wild plants , 1986 .

[45]  D. DeAngelis,et al.  Competition and Coexistence: The Effects of Resource Transport and Supply Rates , 1994, The American Naturalist.

[46]  G. Stanhill.  Book reviewTerrestrial nitrogen cycles: F.E. Clark and T. Rosswall (Editors), Ecological Bulletins 33, NFR (Swedish National Research Council), Stockholm, 1981, 714 pp., US $56.00, ISBN 91-546-0290-4 , 1982 .

[47]  J. H. Manwaring,et al.  Rapid physiological adjustment of roots to localized soil enrichment , 1990, Nature.

[48]  H. Reynolds,et al.  An Analytical Treatment of Root-to-Shoot Ratio and Plant Competition for Soil Nutrient and Light , 1993, The American Naturalist.

[49]  I. R. Johnson,et al.  A model of water flow through plants incorporating shoot/root ‘message’ control of stomatal conductance , 1991 .

[50]  MASS FLOW AND DIFFUSION OF NUTRIENTS TO A ROOT WITH CONSTANT OR ZERO‐SINK UPTAKE I. CONSTANT UPTAKE , 1994 .

[51]  M. Caldwell.  12 – Exploiting Nutrients in Fertile Soil Microsites , 1994 .

[52]  D. Tilman.  Plant Strategies and the Dynamics and Structure of Plant Communities. (MPB-26), Volume 26 , 1988 .

[53]  I. Burke,et al.  Spatial patterns of roots in a semiarid grassland: Abundance of canopy openings and regeneration gaps , 1994 .

[54]  E. Bresler,et al.  Simultaneous transport of solutes and water under transient unsaturated flow conditions , 1973 .

[55]  R. B. Jackson,et al.  Integrating Resource Heterogeneity and Plant Plasticity: Modelling Nitrate and Phosphate Uptake in a Patchy Soil Environment , 1996 .

[56]  E. Mccoy.  A bioenergetic model of plant root growth in soil , 1991 .

[57]  Landscape Distribution of Organisms and the Scaling of Soil Resources , 1994, The American Naturalist.

[58]  R. Grant.  Simulation in ecosys of root growth response to contrasting soil water and nitrogen , 1998 .