COMPARISON OF WHEAT SIMULATION-MODELS UNDER CLIMATE-CHANGE .1. MODEL CALIBRATION AND SENSITIVITY ANALYSES

A comparison of the performance of 5 wheat models was carried out for 2 sites in Europe with considerably different agroclimatic conditions: Rothamsted, UK, and Seville, Spain. The models were calibrated agains t field data sets from both sites. For Rothamsted the measured time co urses of crop growth, evapo-transpiration and nitrogen uptake were rep roduced reasonably well by the different models, except for leaf area index. For Seville, the experimental data set was insufficient for suc h a detailed comparison and mainly simulated results were compared. Th e sensitivity of the model results to stepwise changes in individual w eather variables was then determined. In the different model runs a te mperature rise generally resulted in lower yields, an increase in prec ipitation and atmospheric CO2 concentration resulted in higher yields, and increased variability of weather variables often resulted in lowe r yields with increased yield variability.