Impacts of Climate Change on Grain Sorghum Yield in the Ogallala Aquifer Region, USA

The Ogallala aquifer region consists of 232 counties spread over 8 states of United States is facing declining water levels and deteriorating water quality which in turn affects the crop production in these counties. Coupled with the water stress, the changing climatic conditions also has adverse effects on crop production. The objectives of this study was to generate the future scenarios of grain sorghum production in the Ogallala region for plausible future climates. Three RCM's participating in the North American Regional Climate Change Assessment Program (NARCCAP), used in this study are Canadian RCM (CRCM), Regional Climate Model (RegCM3) and the Hadley Regional Model (HRM3). The RCMs were nested within the AOGCMs for the current period 1971-2000 and for the future period 2041-2070 for A2 emission scenario. Grain sorghum yield were simulated across the study region using the CERES-Sorghum model program available in the DSSAT (Decision Support System for Agrotechnology Transfer) crop simulation model suite. Daily data on rainfall, solar radiation, maximum and minimum temperature generated from the RCM were used as meteorological inputs in the current analysis. Grain sorghum hybrid 'Pioneer 8333' planting date and density were set at 5 June and 160,000 plants per hectare respectively. Simulation results show a decrease in the yield of grain sorghum for A2 emission scenario without considering effects of elevated carbon dioxide and changes in genetics. Results of the study provide critical information needed to help decision/policy makers to device long-term strategies to cope with impacts of climate change and variability on water use and crop production for the Ogallala aquifer region.