A recently released U.S. Department of Agriculture study shows that conservation practices applied to cultivated cropland in the Ohio-Tennessee River Basin are reducing losses of sediment, nitrogen and phosphorus from farm fields and decreasing the movement of these materials into the Mississippi River and other waterways.
The Ohio-Tennessee River Basin Conservation Effects Assessment Project (CEAP) study examines nearly 204,000 square miles in the river basin, including parts of Alabama, Georgia, Illinois, Indiana, Kentucky, Maryland, Mississippi, New York, North Carolina, Ohio, Pennsylvania, Tennessee, Virginia and West Virginia.
Prepared by NRCS, the Ohio-Tennessee River Basin report estimates conservation practices have reduced edge-of-field losses of waterborne sediment by 52%, nitrogen in surface runoff by 35%, nitrogen in subsurface flows by 11% and phosphorus, both attached and soluble, by 33%. Additional model simulations show that from 2003 to 2006, conservation practices in the basin reduced loads of waterborne sediment, nitrogen and phosphorus entering the Mississippi River by 16, 15 and 21%, respectively.
NRCS and its partners determined these losses and loadings by computer model simulations based on scientific data that compare farming and conservation practices from 2003 to 2006 to conditions that would be expected if no conservation practices were in place. USDA’s National Agricultural Statistics Service provided data for the simulations.
The study also shows that nearly 6 million acres – nearly 24% of cultivated cropland in the basin – now have a high level of need for conservation treatments to reduce losses of sediment and nutrients. Modeling simulations show that the most cost-effective way to address these losses is through planning and implementation of appropriate suites of erosion-control and nutrient management practices.
Excessive loss of phosphorus from farm fields is the most critical agricultural conservation concern in the basin. This finding contrasts with findings from the previous studies in other river basins in this series, which found that nitrogen loss through leaching was the most critical agricultural conservation concern.
CEAP cropland studies come from a partnership of NRCS, USDA’s Agricultural Research Service and the Texas AgriLife Research and Extension of Texas A&M University. The Upper Mississippi River Basin, Chesapeake Bay and Great Lakes Region CEAP studies and additional information about the Ohio-Tennessee River Basin project is available on the CEAP Web page at http://go.usa.gov/QWv. Additional regional cropland studies on the effects of conservation practices will be forthcoming over the next several months.