Report: Conservation Work Minimizes Sediment, Nutrient Runoff
Agriculture Secretary Tom Vilsack announced a new U.S. Department of Agriculture (USDA) report that shows farmers have significantly reduced the loss of sediment and nutrients from farm fields through voluntary conservation work in the lower Mississippi River basin. Secretary Vilsack highlighted the value of conservation programs to these efforts, and called on Congress to pass a comprehensive Food, Farm and Jobs Bill that would enable USDA to continue supporting conservation work on farms and ranches.
The report, released by USDA’s Natural Resources Conservation Service (NRCS) this week, marks the completion of a watershed-wide assessment of conservation efforts in the Mississippi River watershed. Its findings demonstrate that conservation work, like controlling erosion and managing nutrients, has reduced the edge-of-field losses of sediment by 35%, nitrogen by 21% and phosphorous by 52%.
“Farmers and ranchers work hard to conserve the land and water, and today’s report shows the tremendous impact they’ve had for the Mississippi River and Gulf of Mexico,” Vilsack said. “We need to keep up the momentum by providing scientific and technical expertise that supports conservation in agriculture. To continue these efforts, we need Congress to act on a comprehensive Food, Farm and Jobs Bill as soon as possible.”
While the report shows the positive impacts of conservation, it also signals the need for additional conservation work. The most critical conservation concern in the region is controlling runoff of surface water and better management of nutrients, meaning the appropriate rate, form, timing and method of application for nitrogen and phosphorous.
Model simulations show that an increase in cover crops will have a significant impact on reducing edge-of-field losses of sediment and nutrients and improve water quality.
The information in the report will help further develop NRCS’ work in the Mississippi River Basin Healthy Watersheds Initiative and Gulf of Mexico Initiative, aimed at helping producers improve water quality, restore wetlands and sustain agricultural profitability.
The report is part of USDA’s Conservation Effects Assessment Project, or CEAP, which uses advanced modeling techniques to assess the effects of conservation practices. The lower Mississippi report covers cropland in Louisiana, Arkansas, Kentucky, Mississippi, Missouri and Tennessee.
By comparing losses of sediment and nutrients from cultivated cropland to losses that would be expected if conservation practices weren’t used, CEAP reports give science-based insight into the techniques that most benefit water quality, soil health and other resource concerns.
“These assessments are part of the scientific backbone that helps us work with farmers to get the right conservation techniques on the right acres,” said NRCS Chief, Jason Weller. “A focus on the most effective conservation techniques means that we’re helping to deliver the best results for farmers and our natural resources.”
Over the past few years, similar assessments were completed in the upper Mississippi River, Tennessee-Ohio, Missouri and Arkansas-Red-White basins. As a whole, assessments in this project have shown:
- Conservation on cropland prevents an estimated 243 million tons of sediment, 2.1 billion pounds of nitrogen and 375 million pounds of phosphorus from leaving fields each year. These figures translate to a 55 percent, 34 percent and 46 percent reduction in sediment, nitrogen and phosphorus edge-of-field losses, respectively, compared to what would have been lost if no conservation practices were in place.
- Similarly, conservation has resulted in an estimated 17 percent reduction in nitrogen and 22 percent reduction in phosphorus entering the Gulf of Mexico annually. An additional reduction of 15 percent of nitrogen and 12 percent of phosphorus can be achieved by implementing comprehensive conservation plans on all cropland in the basin in areas that have not adequately addressed nutrient loss.
The scientific-based modeling also pointed out that higher rainfall and more intense storms lead to higher edge-of-field losses of sediment and nutrients in the lower Mississippi River basin than the other four basins in the Mississippi River watershed. Because of this, more soil erosion control and better management of nutrients are important in the basin.