1a. Objectives (from AD-416):
The overall objective of our research is to sustain agriculture and water resources in the northeastern US. Our basic research provides fundamental information on processes (chemical, physical, hydrologic), linking agricultural management with water resources. Our applied research advances nutrient management practices and strategies that balance production and agroecological services, helping agriculture to adapt to emerging water resource issues and, ultimately, promoting resilient agroecosystems that can respond to long-term challenges occurring at scales beyond the farm gate. Specific objectives are: (1) Describe and quantify processes controlling agriculturally related environmental contaminants (nutrients, trace metals, and sediments). (2) Adapt and develop management practices and strategies that farmers can use to reduce the environmental impacts of agriculturally derived contaminants. (3) Conduct watershed scale research to understand the long-term impacts of changing management and climate on water resources.
1b. Approach (from AD-416):
Research will span the four major physiographic provinces of the Chesapeake Bay watershed, relying upon core sites in the Atlantic Coastal Plain (Manokin watershed, MD), Appalachian Piedmont (Conewago watershed, PA), Appalachian Valley and Ridge (Mahantango Creek watershed, PA and Spring Creek watershed, PA), and Allegheny Plateau (Anderson Creek watershed, PA) (Figure 1). Research emphases will vary across these provinces, reflecting issues that are of current management or scientific relevance as well as constraints imposed by available resources (Figure 2). Our primary distinction is between the Atlantic Coastal Plain and upland physiographic regions, as hydrologic flow paths are dramatically different in these landscapes (subsurface flow is the dominant hydrologic pathway in the Atlantic Coastal Plain whereas overland and shallow lateral flows are the major pathways in the upland provinces). We have landowner contacts and research collaborators at all major (core) sites, and have a research infrastructure that enables routine measurement and chemical sampling of surface runoff, subsurface flow, and stream flow. When necessary, we move infrastructure from one location to another to provide a greater intensity of observations. We combine field observations with laboratory experiments in which greater control may be obtained over indirect variables. Our process-oriented research (Objective 1) involves observational and experimental studies, using parametric and nonparametric statistics to quantify temporal and spatial trends or to determine differences between management/land use, landscape units, and watershed components. Our applied research (Objectives 2 and 3) includes experimental studies, remote sensing and modeling. Experimentation involves a high degree of replication due to the inherent variability in processes impacting water quality. We have strong in-house statistical capability and, when necessary, consult with outside statisticians to ensure confidence in our findings.
3. Progress Report:
This project was initiated in April, 2012, with major activities focused on the five sub-watersheds (Manokin River, Conewago Creek, Mahantango Creek, Spring Creek, Anderson Run) selected to represent the four major physiographic provinces of the Chesapeake Bay watershed. The full suite of planned projects was initiated, involving baseline laboratory studies to assess chemical processes, construction of monitoring instruments, and experimental equipment/treatments, and development of databases. Under Objective 1, laboratory studies were established to elucidate the chemical controls of arsenic fate in heavily manured soils where poultry litter had been historically applied, developing competition isotherms to explore the interaction between phosphorus and arsenic that we hypothesize exacerbates arsenic solubility in Delmarva Peninsula soils. Field studies were implemented in Pennsylvania to better understand the chemical controls of nitrogen cycling around manure injection zones. A new monolith sampler was developed to enable us to sample soil profiles around a manure injection furrow, and was used to assess spatial variability in soil nitrate. This information will contribute to Penn State recommendations on soil sampling for the Pre-side dress nitrate test (PSNT). Under Objectives 1 and 2, new monitoring networks were established to elucidate critical pathways of urea and arsenic transport (Manokin River watershed), and improve runoff generation models that are used to guide nutrient management planning (all other watersheds). Ground penetrating radar and electromagnetic scans were carried out at all upland watershed sites to evaluate soil properties and support a pedogenic model that will be used to improve the utility of soil maps in identifying soils prone to runoff. Under Objective 3, we developed an SCA with the Penn State Center for Environmental Informatics to develop a field management database for Mahantango Creek’s WE-38 watershed that will enable us to examine historical trends in management within a GIS framework. In addition, existing WE-38 hydrologic, precipitation and water quality databases were updated. At time of report submission, discussion was underway with other ARS units to apply similar databases to the development of a network that will be used to evaluate alternative nutrient management planning tools, including the SWAT and APEX models and the Phosphorus Index.