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A Simplified Soil and Plant Phosphorus Model: I. Documentation
Author(s) -
Jones C. A.,
Cole C. V.,
Sharpley A. N.,
Williams J. R.
Publication year - 1984
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1984.03615995004800040020x
Subject(s) - mineralization (soil science) , chemistry , fertilizer , agronomy , soil organic matter , organic matter , tillage , humus , environmental science , plough , environmental chemistry , soil science , soil water , biology , organic chemistry
Abstract The structure of a simple soil and plant P model designed for use in the Erosion‐Productivity Impact Calculator (EPIC) agriculture management model is described. The model maintains pools of stable, active, and labile inorganic P; fresh organic and stable organic P; and grain, stover and root P. The model has a daily time step, simulates P uptake and transformations in up to ten soil layers of variable thickness, and is sensitive to soil chemical and physical properties, crop P requirements, tillage practice, fertilizer rate, soil temperature, and soil water content. Fertilizer P is added to the labile inorganic P pool which is in rapid equilibrium with the active inorganic P pool. The relative sizes of the labile and active inorganic pools are soil specific and are based on soil classification, texture, and chemical properties. Movement of active inorganic P to the stable inorganic P pool simulates slow adsorption of inorganic P. Crop P uptake from a soil layer is sensitive to crop P demand and the amounts of labile P, soil water, and roots in the layer. Stover and root P are added to the fresh organic P pool upon their death and/or incorporation into the soil. Decomposition of fresh and stable organic matter may result in net immobilization of labile P or net mineralization of organic P.