PREPARING THE EROSION PRODUCTIVITY IMPACT CALCULATOR (EPIC) MODEL TO SIMULATE CROP RESPONSE TO CLIMATE CHANGE AND THE DIRECT EFFECTS OF CO2

The adaptation of a crop simulation model to deal with the impacts of rising CO2 and climate change is described in this paper. Algorithms that represent the direct effects of atmospheric CO2 on crop photosynthetic efficiency and water use were developed for use with the erosion productivity impact calculator (EPIC), a mechanistic crop simulation model. Representative farms were designed to reflect the major cropping systems in the MINK (Missouri-Iowa-Nebraska-Kansas) region and data were assembled to simulate them in EPIC. Climate data were compiled to represent conditions under the control (1951-1980) and analog (1931-1940) climates. Actual daily temperature and precipitation data from a number of climatological stations across the MINK region were used in the simulations. Daily values of solar radiation, relative humidity, and wind speed were simulated stochastically from monthly First Order Weather Station records.