Drivers of spatial and temporal variation in soybean yield and irrigation requirements in the western US Corn Belt

摘要: Abstract Both rainfed and irrigated soybean production are important in Nebraska (western US Corn Belt), accounting for a respective 48 52% of the state's 7 Mt on 55 45% share state area 1.9 Mha. To date, no assessment factors that may account regional inter-annual variation yield irrigation amount has been performed. accomplish objective, we evaluated database containing on-farm field yields total used those fields. These data have collected annually from ca. 1000 fields six regions during past eight years. Distributions farm were analyzed impact selected weather variables key management these two was assessed. For soybean, attainable estimated 95th percentile distribution, gaps then calculated as difference between average yield. The interquartile range measure gap skillfully sub-optimally managed Distribution skewed, indicating many producers achieved relatively close to yield, but also excess needed occurred an fraction Variation strongly related July–August rainfall seasonal water deficit, but, contrast, single meteorological factor could consistently explain In fact, sowing date explained most observed all regions. Amount applied each year depended both reference evapotranspiration. Efficiency use versus produce seed remarkably similar. Across regions, NE averaged 4.7 Mg ha −1 , with averaging about 16% among more than years even Further research is identify causes this field-to-field within same region.