1a. Objectives (from AD-416)
The overall goal of research is to identify chemical and hydrologic processes controlling nutrient export at farm and watershed scales, locate where they occur on the landscape, quantify what changes occur during transport in stream to receiving waters, and develop, implement, and assess cost-effective Best Management Practices (BMPs) control of nutrient export at farm and watershed levels. Specific objectives are: 1. Quantify impacts of current and alternative fertilizer, manure, crop, and grazing management practices on nutrient cycling within soils at point and field scales. Effective June 15, 2007, research on Objective 1.3: “Quantify NH3 and N2O emissions from urine deposition during grazing” was terminated, and this effort was redirected to Objectives 3.2 and 3.3. 2. Evaluate landscape-scale controls on nutrient transfers to quantify aggregate N and P losses from farming systems and watersheds typical of the Northeast. 3. Identify and quantify processes occurring in the stream channel that control the transfer of nutrients lost from the farm to lakes, reservoirs, and estuaries. Effective June 15, 2007, resources previously allocated to Objective 1.3 were redeployed to accelerate work on Objectives 3.2: “Selecting chemical amendments to reduce P mobility in terrestrial and aquatic systems” and Objective 3.3: “Control nutrient export from ditch drained agriculture” with a focus on the use of industrial byproducts coupled with drainage practices in agricultural and urban landscapes to minimize impact on water quality within the Chesapeake Bay watershed. 4. Determine effectiveness of BMPs in the Cannonsville/Town Brook Watershed and other appropriate watersheds (CEAP-related). 5. Develop, enhance, and apply models and user-oriented indices at field, farm, and watershed scales to evaluate BMPs and N and P export from watersheds.
1b. Approach (from AD-416)
Most of the proposed research will be conducted at three sites in the Northeast U.S.: Mahantango Creek Watershed, PA; Town Brook Watershed, NY; and Manokin River Watershed, MD (Figure 3). These sites are located in agriculturally important areas of the Northeast and reflect the local land use practices. We already have established contacts with landowners at each site and have developed an infrastructure for routine measurement and chemical sampling of surface runoff, subsurface flow, and streamflow. Lease agreements already in place make it easy for us to change management and/or implement alternative practices for cause-and-effect studies on water quality impacts. Also included in this section is a description of the National P Research Project (NPRP) rainfall simulation protocol. Experimental design will vary as a function of each specific research objective and site characteristics. In all cases, appropriate experimental design and statistical analyses will be used.
3. Progress Report
Progress was made on all five objectives and their subobjectives, which fall under National Program 211, Problem areas 1 (Effectiveness of Conservation Practices), 3 (Drainage Water Management Systems) and 5 (Watershed Management, Water Availability and Ecosystem Restoration). Under objective 1, we completed planned data collection efforts related to alternative manure management practices, enhanced nitrogen fertilizers and precision nitrogen management. This research supports regional (Chesapeake Bay Watershed) and national initiatives to develop and transfer next generation nutrient management practices, and is of interest internationally in areas where anthropogenic eutrophication is a concern (European Union, Australia/New Zealand, China). Under objective 2, monitoring activities in Pennsylvania and Maryland were summarized, elucidating sources of sediment and nutrient export at landscape and watershed scales. This research supports the targeting of remedial practices to improve the health of the Chesapeake Bay and its tributaries, and serves as the basis for new model development in Objective 5. Under objective 3, we made significant progress toward improving our understanding of the processes controlling nutrient and trace element transport in ditches and streams of the Eastern Shore of Maryland and in developing new practices to improve ditch water quality. Permeable reactive barriers were installed along field edges to trap groundwater phosphorus before it enters the drainage ditch system. A grant was obtained to test these barriers under real world conditions on farms in the area. Under objective 4, progress was made toward the compilation, formatting and transfer of 25 to 40 years of flow, precipitation, water quality and GIS data from the Mahantango, PA WE-38 Watershed for the STEWARDS database, a national database of Conservation Effects Assessment Project watersheds. Under objective 5, progress was made toward developing a new runoff forecasting model, using weather forecast data from the Pennsylvania climatologist. This model will serve as the basis for a next-generation nutrient management tool to provide tactical (daily) support to farmers on field suitability for manure application.
1. Improving fertilizer nitrogen use by corn in mid-Atlantic landscapes: The sloping landscapes of the mid-Atlantic region have a distinct hydrology that can result in substantial differences in soil moisture availability during the growing season. ARS scientists (at University Park, PA) demonstrated that improving nitrogen use efficiency by corn requires a better agronomic understanding of the interaction between water at a particular landscape position and nitrogen availability to the crop. Our findings show that when adequate soil moisture is maintained during the growing season, corn grain yield is directly related to nitrogen availability, but when soil water availability is low, nitrogen fertilizer has little effect on grain yield. Results support the ongoing improvement of precision nitrogen recommendations in sloping, mid-Atlantic landscapes.
2. Balancing environmental and agronomic trade-offs with new poultry manure applicators: New technologies are being adopted to improve the incorporation of manures into soils with minimal disturbance. ARS scientists (at University Park, PA) evaluated phosphorus losses in surface and subsurface flow as well as crop yields from a novel poultry manure applicator developed by USDA-ARS. In the unique soils of the Delmarva Peninsula, a spit of land forming the eastern banks of the Chesapeake Bay and home to a robust poultry industry, subsurface placement of dry poultry manure can exacerbate the leaching of phosphorus compared to conventional methods. However, minor modifications are likely sufficient to prevent this process.
3. Closing the curtains on phosphorus losses from agricultural fields to drainage ditches: The loss of phosphorus in shallow groundwater leaving fields of the Delmarva Peninsula can account for more than 90% of the phosphorus exported by drainage ditches to tributaries of the Chesapeake Bay. ARS scientists (at University Park, PA) installed a curtain of gypsum along the border of a field from which high loads of phosphorus had previously been recorded in groundwater. The new curtain, or permeable reactive barrier, removed 38-59% of the dissolved phosphorus in groundwater in the first rain storms after it was installed. New efforts are underway to expand the testing of this water quality enhancement practice in other areas of the region.
5. Significant Activities that Support Special Target Populations
Scientists have participated in activities targeting minority, historically under-served operators/stakeholders including: 1) collaborator on development of a Capacity Building Grant proposal; $500,000 was awarded to the University of Maryland Eastern Shore (UMES) to conduct a “Watershed Level Examination of Urea Use as Fertilizer and the Production of the Biotoxin Domoic Acid;” 2) collaborator on development of a Capacity Building Grant proposal; $600,000 was awarded to UMES to assess “Development of a Subsurface Application Technology for Dry Poultry Litter to Protect Air and Water Quality;” 3) collaborator on development of a Conservation Innovation Grant proposal; $1,000,000 plus $1,000,000 matching was awarded to UMES to transfer the new technology “Gypsum Curtains: Reducing Soluble Phosphorus (P) Losses from P-Saturated Soils on Poultry Operations;” (4) co-sponsoring the 2010 Manure Expo where research from ARS-UMES collaboration was highlighted.