Location: Water Quality and Ecology ResearchTitle: Crop conversion impacts on runoff and sediment loads in the Upper Sunflower River Watershed
|MOMM, HENRIQUE - Middle Tennessee State University|
|PORTER, WESLEY - Middle Tennessee State University|
|ELKADIRI, RACHA - Middle Tennessee State University|
|Bingner, Ronald - Ron|
|ABER, JOE - Middle Tennessee State University|
Submitted to: Agricultural Water Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/2/2019
Publication Date: 5/20/2019
Citation: Momm, H.G., Porter, W.S., Yasarer, L.M., Elkadiri, R., Bingner, R.L., Aber, J. 2019. Crop conversion impacts on runoff and sediment loads in the Upper Sunflower River Watershed. Agricultural Water Management. (217):399-412. https://doi.org/10.1016/j.agwat.2019.03.012.
Interpretive Summary: 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 watershed modeling technology, specifically the Annualized Agriculture Non-Point Source (AnnAGNPS) watershed pollution model, 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 type and irrigation applications.
Technical Abstract: The Mississippi River alluvial floodplain is one of the most productive agricultural regions in the United States. In recent decades, factors of economic forces and government policies have driven crop selection and respective farming management changes in this region. This study quantified the effects of changes in crop conversion and farming management practices to discharge and sediment loads at the Upper Sunflower River watershed. Farming and climate conditions were dynamically characterized in space and time by integrating annual crop yield at the county scale, annual crop irrigation at the field scale, and an enhanced description of precipitation. This information was used as input into the Annualized Agriculture Non-Point Source (AnnAGNPS) watershed pollution model to describe existing conditions and simulate alternative scenarios. Simulations considering high irrigation adoption indicated short-term increases in flow at the outlet. Simulations considering a future trend of crop conversion to corn/soybean indicate a potential reduction in average annual sediment loads. As irrigation increases and crop production continues to shift towards corn/soybeans, these findings support the development of responsible irrigation management strategies designed for efficient water usage coupled with implementation of in field conservation practices for reduced sediment loads.