| The CERES-Maize model was evaluated in its capacity to predict both regional maize yield and water use within the United States Department of Agriculture (USDA) Economic Research Service (ERS) Region 1 between the years 1997--2007. A grid based, geospatially explicit method was developed to express the various rainfed and irrigated maize cultivars grown across the region. Overall, the calibrated model compared well for both physiological and yield parameters, producing significant linear relationships (p<0.05) between observed and predicted values for days to anthesis, days to maturity, and total yield under both rainfed and irrigated conditions. The validation results also produced strong correlations for days to anthesis and total yield; however days to maturity did not compare as well (R2<0.5). After the calibration and validation process, regional estimates of evapotranspiration and irrigation for eastern Nebraska and South Dakota were produced. The results were comparable to previous studies in the region.;The calibrated and validated CERES-Maize model was used to predict potential evapotranspiration and yield under three IPCC weather scenarios for the year 2050 to evaluate crop production under climate change. Regional evapotranspiration was predicted to increase for both rainfed and irrigated maize; however, declines were predicted in rainfed evapotranspiration for the states of Indiana and Ohio. Regional maize yields were predicted to increase under both rainfed and irrigation conditions compared to the baseline (1997--2007) conditions. Despite the increases in overall maize yield projected across the region as a whole, large declines were observed in certain areas such as Illinois, Indiana, and Ohio under rainfed conditions and South Dakota under irrigated conditions. Overall irrigation demands declined in Nebraska and South Dakota. The results suggest that maize production could improve under climate change scenarios, and shifts in production to western locations could maximize production in 2050. |
