Quantify Effects of Integrated Land Management on Water Quality in Agricultural Landscape in South Fork Watershed, Iowa River

Abstract:

Sustainable biofuel feedstock production — environmental sustainability and economic sustainability — may be achieved by using a multi-faceted approach. This study focuses on quantifying the water sustainability of an integrated landscaping strategy, by which current land use and land management, cropping system, agricultural Best Management Practices (BMPs), and economics play equal roles. The strategy was applied to the South Fork watershed, IA, including the tributaries of Tipton and Beaver Creeks, which expand to 800-km² drainage areas. The watershed is an agricultural dominant area covered with row-crops production. On the basis of profitability, switchgrass was chosen as a replacement for row crops in low-productivity land. Areas for harvesting agricultural residue were selected on the basis of soil conservation principals. Double cropping with a cover crop was established to further reduce soil loss. Vegetation buffer strips were in place at fields and in riparian areas for water quality control, resource conservation, and eco service improvement. The Soil and Water Assessment Tool (SWAT) was applied to evaluate source reduction under various management schemes and land use changes. SWAT modeling incorporated 10-yr meteorological information, soil data, land slope classification, land use, four-year crop-rotation cycle, and management operations. Tile drain and pothole parameters were modeled to assess the fate and transport of nutrients. The influence of landscape management and cropping systems on nitrogen and phosphorus loadings, erosion process, and hydrological performance at the sub-watershed scale was analyzed and key factors identified. Results suggest strongly that incorporating agricultural BMPs and conservation strategies into integrated landscape management for certain energy crops in row-crop production regions can be economical and environmentally sustainable.