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
Activities for this project fall under ARS National Program 211, and contribute to NP211 Problem Areas 1 (Effectiveness of Conservation Practices), 3 (Drainage Water Management Systems) and 5 (Watershed Management, Water Availability and Ecosystem Restoration). Under objective 1, publications were developed on novel practices to improve manure and fertilizer application. We developed a special issue of Journal of Environmental Quality on novel manure management practices, as well as papers on a active leaf sensor to improve split application of nitrogen in corn. These findings support state (PA, DE, MD, NY and VA) efforts to respond to the Chesapeake Bay TMDL and are expected to impact over 10,000 acres of farmland in the Chesapeake Bay watershed. Under objective 2, publications were developed that quantify sources of stream sediment discharge and pathways of nutrient transport from hillslopes to streams. Our finding that field erosion accounts for the majority of watershed sediment loads, derived from research in the Ridge and Valley region of the Chesapeake Bay watershed, provides an important contrast to previous studies in the Piedmont region of the Bay watershed that found bank erosion to be most important. Research on critical flow pathways of nutrients and short-term predictions of runoff generation serves as the basis for next-generation site assessment tools. Under objective 3, we presented and/or published findings on field, edge-of-field and within-ditch practices to minimize nutrient and trace element transfers in ditch drained areas of the Coastal Plain region. New methods to filter runoff developed under this objective are now featured in USEPA’s 2010 Chesapeake Bay TMDL as next generation nutrient management practices. Under objective 4, five papers were published summarizing information related to the Mahantango Creek watershed database. This database includes 40 years of flow and water quality information and is available on-line as part of ARS’s STEWARDS database. Our approach to formally publishing watershed meta-data sets precedent for other watersheds in the STEWARDS database. Under objective 5, presentations and publications were developed on farm-scale model evaluations of alternative manure management strategies and on the development of a runoff forecasting model tied to daily weather forecasts. Findings from this objective demonstrate that new manure injection technologies are economically benign or advantageous while improving air and water quality and prove that weather forecasts can be modified to provide daily support of nutrient management decisions.
1. Quantified environmental and economic benefits of manure injection technologies. ARS scientists in University Park, PA, Booneville, AR, and Auburn, AL, along with their colleagues at land grant universities in five mid-Atlantic states, conducted research on new methods to incorporate manure into soils as an alternative to the more common method of applying manure to the soil surface. The researchers quantified the benefits of injecting manures into soils with different technologies, demonstrating the potential of new shallow injection technologies to lower odor to background levels within 3 hours, decrease ammonia emissions by more than 70% and reduce phosphorus in runoff to levels comparable to soils that did not receive manure. Manure injection also results in minimal soil disturbance which reduces erosion in comparison to conventional tillage. Research showed that costs of purchasing and maintaining manure injectors were balanced, even outweighed, by improved manure nutrient use by crops. As a result of this work, state and federal initiatives in the Chesapeake Bay watershed include plans to expand the use of manure injection technologies to more than 47,500 acres of agricultural land. The USDA and university researchers received the 2011 Mid-Atlantic Regional Educational Institution and Federal Laboratory Partnership Award and their work is cited in the Watershed Implementation Plans developed by MD, NY, PA and VA.
2. New sensor shown to improve fertilizer nitrogen use efficiency by corn across Pennsylvania. USDA-ARS research with a canopy sensor provides the basis for matching corn nitrogen requirements with nitrogen fertilizer rates that will yield the optimum economic return and minimize nitrogen losses to the environment. Traditional fertilizer management practices deliver less than 50% of nitrogen in fertilizer to growing corn crops. ARS scientists at University Park, PA, showed that, compared with other methods of guiding nitrogen fertilizer rates, a canopy reflectance sensor provided recommendations that best matched the economic optimum fertilizer rate. Besides providing more accurate nitrogen recommendations, the sensor provides immediate results and can be used to tailor fertilizer application rates to variable soil conditions within a field. This technology, while still new to PA, provides a way to improve nitrogen applications to corn, thus improving return for the farmer and reducing environmental losses in critical watersheds such as the Chesapeake Bay.
Penn, C.J., Bryant, R.B., Callahan, M.P., Mcgrath, J.M. 2011. Use of industrial by-products to sorb and retain phosphorus. Communications in Soil Science and Plant Analysis. 42:633-644.