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
FY-2008 represents the first full year of activity under 1902-11130-011. Research under all objectives was initiated and all milestones successfully met. Progress on objectives was maintained via daily contact between scientists, periodic meetings, ad hoc meetings of scientists working on individual projects. Objective 1. To quantify the impacts of fertilizer and manure impacts at plot and field scales, field plots were established at sites across Pennsylvania and Maryland and research initiated with six different liquid manure application systems, a litter injection system and a crop nitrogen sensor. Preliminary results indicate that prudent use of precision application methods can minimize environmental losses of nutrients while supporting, even improving, nutrient use efficiency. With the purchase of a new inductively coupled plasma optical emission spectrometer we initiated studies on trace element transport, finding a likely interaction between phosphorus and trace elements during transport from heavily-manured soils of the Delmarva Peninsula. Objective 2. To evaluate landscape controls on nutrient transport, runoff and leaching experiments were conducted in which manures were mixed with rare earth elements and amended to packed boxes and soil columns that were subjected to rainfall simulations. A study involving electrical resistivity tomography was implemented in the USDA-ARS FD-36 watershed from which gaining and losing stream reaches were identified. Additionally, soil and sediment samples were obtained and submitted for 137-Cs analysis as part of a study to identify sources of sediment from the larger WE-38 watershed. Objective 3. To better understand the modifying effect of within-stream processes on watershed nutrient transport, sediments were obtained from the Princess Anne, MD research site and subjected to flume experiments. A purpose-built drainage ditch filter was tested at the site, with preliminary results suggesting at least 40% phosphorus removal efficiency for an 8 ha catchment. After completing baseline monitoring of drainage ditches on the Eastern Shore of Maryland, initiated testing of ditch dredging. Objective 4. Continued to participate in CEAP and have successfully completed the transfer of WE-38 watershed data to the STEWARDS database. Supported a workshop sponsored by the New York City Department of Environmental Protection featuring work from the National Sedimentation Laboratory. This workshop will support the next phase of New York’s water quality protection program. Objective 5. Completed two modeling studies of manure incorporation as an alternative to broadcasting manure to no-till soils on Pennsylvania dairy farms. One preliminary study extended field results from objective 1 to determine the feasibility of adopting new technologies. Results suggest shallow disk injection has the greatest potential. The other study evaluated the effect of using rainfall simulation results in evaluating environmental trade-offs in no-till systems, finding that temporal fluctuations in nutrient and sediment transport must be considered before system level conclusions can be made. NP211 Problem Area 1, and Problem Area 6
1. Few management recommendations exist for agricultural drainage ditches even though they are a critical landscape feature that can be managed to protect water quality: Agricultural drainage ditches are ubiquitous features that are often ignored in agricultural management even though they link fields with downstream water bodies. Our research on the Eastern Shore of Maryland demonstrates that ditches are much more than simple conduits of agricultural runoff and that they can be managed to buffer downstream water quality impacts. Traditional ditch management practices such as dredging and vegetation removal must be reevaluated in this light, as they may actually exacerbate nutrient and sediment losses from fields. Through monitoring and field testing we demonstrate that nutrient and sediment transfers in ditches are regulated by dynamic processes that can be managed with conventional and novel approaches. This research culminated in the first national conference on drainage ditch management and is the basis for new ditch management practices that are currently being tested. Addresses NP211 Problem Area 6: "Water quality protection systems;" Output/Product 1: "Scientific information regarding nutrient retention, transformation and transport processes, and field management techniques that reduce off-site nutrient movement."
2. Low cost filtration methods for agricultural drainage water: The loss of nutrients from heavily manured fields is a major water quality concern and its remediation a national priority. A novel approach to drainage water management is to filter the runoff using low cost materials in areas where diffuse flow in concentrated. Building upon more than a decade of research on alternative uses of industrial byproducts, we evaluated various designs for filtering phosphorus from drainage water. The result is a series of recommendations for filter development that served as the basis for the University of Maryland’s USDA EQIP Conservation Innovation Grant to improve the quality of drainage water from Maryland ditches. Addresses NP211 problem area 6: "Water quality protection systems"; Product 4: "New and improved technologies that remove nutrients from surface or subsurface water."
3. The influence of preferential flow pathways on water movement through soil is difficult to determine, even though these pathways can greatly increase the transfer of fertilizer nutrients and pesticides to groundwater: Using two types of water sampling devices can elucidate the role of preferential flow in leaching processes. We evaluated water and solute movement in fields under no-till and conventional tillage using two different sampling devices. Contrary to the conventional wisdom that no-till increases preferential flow, we found that water flow and solute transport from conventional till were as great or greater than from no-till by comparing results from the two samplers. Findings from this research provide guidance for interpreting results from other research studies in which only one type of sampling device was used. Addresses NP211 Problem Area 6: "Water Quality Protection Systems" Output/Product 1: "Scientific information regarding nutrient retention, transformation and transport processes, and field management techniques that reduce off-site nutrient movement."
5. Significant Activities that Support Special Target Populations