Simulation as a Tool for Analyzing Crop Response to Climate Change

Simulations of soybean and com (maize) growth for the southeastern U.S.A. were run for 30 baseline years of weather data, 1951-80, for 19 locations with and without supplemental irrigation, using SOYGRO and CERES-Maize crop models. Runs were also made for climatic changes predicted by two General Circulation Models (GCMs) for a doubling of atmospheric carbon dioxide. One climate change scenario resulted in over 50% reduction in rainfed seed yields for both crops, while the impact of the second scenario was negligible. Under irrigation, the simulated results indicated doubled CO2 produced 20% less corn and 14% more soybean, somewhat independent of the climate change scenario. Irrigation water demand was significantly increased.