2007 Annual Report 1a.Objectives (from AD-416) Increase BMP Implementation and reduce nutrient and sediment loads in the Tuckahoe basin through: enrollment of 6,000 acres per year in a commodity cover crop pilot program to determine the feasibility of large-scale implementation; and installation of six drainage management structures at strategic locations within the watershed. Nitrogen reductions are estimated at 31,600 lbs/yr. Development of improved nutrient removal efficiencies for cover crops, commodity cover crops, and drainage control structures using an innovative approach that combines water quality monitoring, remote sensing, and crop modeling on a field scale. Incorporate these nutrient removal efficiencies into a spatially explicit, watershed water quality model (AnnAGNPs) that utilizes detailed land-use and water quality data to estimate current nutrient loading and removal parameters. Utilize the refined model in the development of a flexible, user-friendly BMP planning tool incorporating costs for implementation/nutrient reduction for the Choptank River watershed. This model will be used by MDA staff to cost-effectively design BMP implementation plans that will achieve the greatest reductions in nutrients and sediments. 1b.Approach (from AD-416) This project will increase agricultural BMP implementation in the Tuckahoe sub-basin and reduce overall nutrient and sediment loads to Tuckahoe Creek and the Choptank River. It will result in the development of improved nutrient reduction efficiencies for conventional cover crop, commodity cover crop and drainage control structures by monitoring nutrient transport and fate. This project will also result in the development of a flexible, user-friendly BMP planning tool based on a calibrated AnnAGNPS model. The project will calibrate the AnnAGNPS model to tidal conditions of the Choptank. 3.Progress Report This report documents research conducted under an Interagency Reimbursable Agreement between the ARS and the Maryland Department of Agriculture. Additional details of research can be found in the report for the parent project 1265-12130-002-00D, "Assessing climate, soil and landscape processes affecting agricultural ecosystems.” Substantial progress has been made on this project. Five on-farm drainage control sites have been established where water quality and denitrification effects are monitored on an ongoing basis. Each site has been outfitted with a compound weir to provide flow measurement, a water level detector to continuously monitor water flux through the weir, an automated sampler to record flow data and collect event water samples, and a solar panel power supply. Beginning in October 2006, water samples were collected from each of these sites on an approximately biweekly basis under base-flow conditions (40 samples total). Event samples were collected at two of the sites on January 1st, 2007, and at three of the sites on March 2nd (59 samples total). Overall, monitoring at the drainage control structures has been through an initiation period to address technical difficulties and monitoring operations are now well functioning. Initial difficulties encountered include finding appropriate pre-post monitoring sites (three are currently under consideration), maintaining water level detectors (four units were sent out for certified factory repair) and triggering event sample collection at two of the sites (due to faulty water level detectors). Four of the sites have had pairs of piezometers (stream bank and in-stream) installed upstream and downstream of the drainage control structures to provide groundwater samples for the analysis of nutrients, dissolved gasses, and isotopic ratios of N and O. These wells have been sampled on a monthly basis since October 2006 (153 samples total). Remote sensing and on-farm sampling to support the quantification of cover crop performance in the Tuckahoe Basin of the Choptank River was successfully conducted in December 2006 (fall growth) and in March 2007 (spring growth). In the 2006-2007 cover crop growing season, 317 fields within the Tuckahoe Basin were enrolled in the Cover Crop and Small Grain Enhancement cover crop cost share programs, totaling 10,450 acres of wheat, 1370 of rye, 3210 of barley, and 1110 of canola. Agronomic information and field boundaries were successfully obtained from MDA personnel and homogenous areas within each field were digitized using ArcMap. These areas will be used to compare satellite vegetation indices to ground monitoring data, once sample analysis is complete.