Simulation of nitrogen, tillage, and residue management effects on soil fertility

A comprehensive simulation model of the soil-crop-water system has been developed as a management tool for nitrogen, tillage, and crop residues. The overall model integrates process level submodels for water flow, crop growth (including roots), nitrogen transformations, tillage effects, soil temperature, soil chemistry, and solute transport to provide an Interactive process simulation. The nitrogen-tillage-residue management model is capable of seasonal and longer-term estimates of soil fertility and its effects on crop yield. Model validation and verification have been obtained for each submodel and for the overall model package. Output from the model can be used in farm and extension level management programs and models, in research and engineering studies, and in teaching programs. The NTRM1 model has been made “user friendly” by developing an extensive user operating system, computer graphics capabilities, and user documentation. The model can be directly accessed via remote terminals through Telenet or similar telephone systems, and the ANSI standard FORTRAN source code is available for adaptation to a specific computer.