Skip to main content
U.S. flag

An official website of the United States government

Quantifying regional effects of best management practices on nutrient losses from agricultural lands

January 12, 2022

Nitrogen (N) and phosphorus (P) losses from agricultural areas have degraded the water quality of downstream rivers, lakes, and oceans. As a result, investment in the adoption of agricultural best management practices (BMPs) has grown, but assessments of their effectiveness at large spatial scales have lagged. This study applies regional Spatially Referenced Regression On Watershed-attributes (SPARROW) models developed for the Midwest, Northeast, and Southeast United States to quantify potential regional effects of BMPs on nutrient losses from agricultural lands. These models were used because they account for specific BMPs in the prediction of instream nutrient loads. The BMPs included in the models were cover crops, no-till, and conservation tillage. Sensitivity testing for the BMPs on agricultural nutrient loads was done using simulations that varied the intensity of BMPs specified in each region. When the BMP intensity was increased 50% relative to the 2012 intensity, the predicted agricultural load of total P decreased across all regions (4% to 14%). The predicted reduction in average P yields in the Midwest, Northeast, and Southeast was 706, 544, and 26 kg km–2, respectively. Increasing BMPs by 50% decreased predicted agricultural total N loads by 3.5% in the Southeast but increased predicted N loads in the Midwest and Northeast by 4.7% and 1.8%, respectively. Model-predicted average N yields increased by 402 kg km–2 and 302 kg km–2 in the Midwest and Northeast, respectively, and decreased in the Southeast by 329 kg km–2. In model simulations, cover crops were more effective at reducing N and P loads than the tillage BMPs despite lower intensity of implementation in 2012. However, at the regional scale of this investigation, implementation of BMPs result in only moderate predicted effects on agricultural nutrient loads

Publication Year 2022
Title Quantifying regional effects of best management practices on nutrient losses from agricultural lands
DOI 10.2489/jswc.2022.00162
Authors Victor L. Roland, Ana María García, David A. Saad, Scott W. Ator, Dale M. Robertson, Gregory E. Schwarz
Publication Type Article
Publication Subtype Journal Article
Series Title Journal of Soil and Water Conservation
Index ID 70227867
Record Source USGS Publications Warehouse
USGS Organization Wisconsin Water Science Center; South Atlantic Water Science Center; Lower Mississippi-Gulf Water Science Center; Maryland-Delaware-District of Columbia Water Science Center