Assessing the effectiveness of winter cover crop on nitrate reduction in two-paired sub-basins on the Coastal Plain of the Chesapeake Bay Watershed

Tuesday, 16 December 2014
Sangchul Lee1, In-Young Yeo1, Ali M. Sadeghi2, Gregory Mccarty2, W. D. Hively3 and Megan W Lang1, (1)University of Maryland, College Park, MD, United States, (2)USDA ARS, Hydrology and Remote Sensing Laboratory, Beltsville, MD, United States, (3)USGS, Eastern Geographic Science Center, Reston, VA, United States
Best management practices (BMPs) have been widely adopted to improve water quality throughout the Chesapeake Bay Watershed (CBW). Winter cover crops (WCC) use has been highlighted for the reduction of nitrate leaching over the fallow season. Although various WCC practices are currently conducted in local croplands, the water quality improvement benefits of WCC have not been studied thoroughly at the watershed scale. The objective of this study is to assess the long-term impacts of WCC on reducing nitrate loadings using a processed-based watershed model, Soil and Water Assessment Tool (SWAT). Remote sensing based estimates of WCC biomass will be used to calibrate plant growth processes of SWAT and its nutrient cycling. The study will be undertaken in two-paired agricultural watersheds in the Coastal Plain of CBW. Multiple WCC practice scenarios will be prepared to investigate how nitrate loading varies with crop species, planting dates, and implementation areas. The performance of WCC on two-paired watersheds will be compared in order to understand the effects of different watershed characteristics on nitrate uptake by crops. The results will demonstrate the nitrate reduction efficiency of different WCC practices and identify the targeting area for WCC implementation at the watershed scale. This study will not only integrate remote sensing data into the physically based model but also extend our understandings of WCC functions. This will provide key information for effective conservation decision making.

Key words: Water quality, Chesapeake Bay Watershed, Winter Cover Crop, Soil and Water Assessment Tool (SWAT)