Proceedings of the 2019 Mississippi Water Resources Conference

Year: 2019 Authors: Bingner R.L., Momm H.G., Porter W.S., Yasarer L., ElKadiri R., Aber J.

The Mississippi River alluvial floodplain is one of the most productive agricultural regions in the United States and the Upper Sunflower River watershed is an important part of this region. Over the past decade, land-use patterns in the Upper Sunflower River watershed have shifted to include more corn and soybean cropland and less cotton. In addition, irrigation adoption has increased from approximately 26% of the watershed in 2001 to 43% in 2015. This study uses the USDA Annualized Agriculture Non-Point Source (AnnAGNPS) watershed pollution modeling technology to assess the impacts of these land-use and irrigation changes on runoff and sediment loads in the Upper Sunflower River watershed. Modeling simulations demonstrated that the increase in irrigation adoption increased runoff during the irrigation season, while conversion of cotton to corn and soybean cropland reduced average annual suspended sediment loads. These results provide a starting point for understanding watershed sensitivity to changes in crop and irrigation management practices.