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Ag Field Management Model Now Better, FasterBy Amy Spillman
October 28, 2002
Soil erosion is a major concern to farmers, so many have adopted reduced-tillage or no-till practices that help retain residue on fields and conserve soil moisture.
Although mulching has become common in the real world, the effect of doing so has not been included in a computer model used by many researchers to gain insight into complex agricultural systems--until now.
Simon van Donk, formerly of the University of Georgia (UGA) and currently an agricultural engineer at the Agricultural Research Service's Grain and Marketing Production Research Center in Manhattan, Kan., and his collaborators at UGA and ARS have updated the ENergy and WATer BALance computer model. It now simulates the effects of a mulch layer on soil water content and temperature, soil water evaporation, and crop transpiration--that is, water lost from living plant surfaces.
Development of the ENWATBAL model started more than 25 years ago. The model evaluates the effects that different management practices have on water conservation and soil temperature in the field. The soil temperature is important because it affects nutrient availability, disease development and crop growth.
The model has been a useful tool for investigating questions that are difficult and costly to examine through field studies. However, until it was modified, it could not take into account the effect that mulch might have on a crop system. Among other things, mulch modifies soil temperature, which may be favorable or unfavorable for the growth of a specific crop.
In addition to adding the mulch option, the researchers adjusted some of the mathematical equations in the computer model, making it approximately 50 times faster.
The scientists' modifications have increased the model's applicability, making it even more helpful to agricultural researchers who are working to improve soil, crop and water management practices.
ARS is the chief scientific research agency of the U.S. Department of Agriculture.