Sustainability of Irrigated Bioenergy Sorghum Across the Continental USA

Agroecosystem models are widely used to predict the impacts of agricultural management practices and environmental changes on biomass yields, soil organic carbon (SOC) dynamics and greenhouse gas (GHG) emissions from bioenergy crops. Applying irrigation to bioenergy crops can enhance carbon capture and storage but may also increase the net GHG emissions of produced biomass and bioenergy. The specific objectives of our study were to i) predict biomass yield, soil carbon changes, and GHG emissions of bioenergy sorghum under different irrigation scheduling across cultivated lands in the continental US, and ii) identify economically optimal, location-specific irrigation treatments for Sorghum cultivation in US. Using multi-location yield data of Sorghum, the process-based agroecosystem model DAYCENT was calibrated, validated, and employed to simulate biomass yield, GHG emissions, and changes in SOC. The DAYCENT model were setup at a 4-km grid scale across the continental US. Long-term weather data, including at least 30 years of temperature and precipitation records, were obtained from the nearest National Oceanic and Atmospheric Administration weather stations. Soil data, including major soil properties were extracted from the SSURGO database by defined soil layers. The model was calibrated using Sorghum yield and SOC data, and further work is under progress to analyze the impacts of irrigation and conduct suitability analysis. Further results including the assessment of irrigated biomass productivity and the economic sustainability of irrigated bioenergy cropping systems will be presented during the meeting.