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United States Department of Agriculture

Agricultural Research Service

Research Project: Comparative Model Simulations with Agricultural Policy Extender (Apex) to Assess the Effects of Management Practices

Location: Crop Systems & Global Change

Project Number: 1245-61660-007-16
Project Type: Specific Cooperative Agreement

Start Date: Feb 10, 2014
End Date: Dec 01, 2015

Objective:
1) Investigate and analyze comparative model simulations with APEX (Agricultural Policy EXtender) to assess the effects of management practices on leaching and runoff of nitrogen and phosphorus, and movement of sediments to the Chesapeake Bay. The project will utilize the APEX model and USDA-NRCS databases used in the Conservation Effects Assessment Program (CEAP); 2) Develop improved algorithms for APEX where simulation results are found to be incorrect; and 3) Communicate methods and results to the EPA's Chesapeake Bay modeling program to help improve their modeling efforts.

Approach:
1. Coordinate with ARS, NRCS, and EPA on refinement needs of CEAP/APEX models to simulate cover crop effects on nutrient and sediment movement in the Chesapeake Bay Watershed and communicate to EPA the CEAP technologies and data used to simulate conservation practices. 2. Define and parameterize APEX scenarios for the 12 major regions in the Chesapeake Bay watershed, e.g., information on tillage, nutrient application, crops, planting dates, cover crops, and weather (approx 47 years). 3. Set up management practice scenarios (cover crops, tillage) to determine the relative effects of management on nutrient (nitrogen, phosphorus) and sediment loss at the edge-of-field or bottom-of-root zone boundary. 4. Carry out model runs and analyze and report results. Compare nitrogen, phosphorus and nutrient dynamics with and without cover crops. 5. Models and results will be reviewed by expert panels and discussed with EPA.

Last Modified: 7/24/2014
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