Location: Pasture Systems & Watershed Management Research
2024 Annual Report
Objectives
Objective 1. Describe and quantify sources and transport processes that transfer agriculturally derived environmental contaminants to receiving waters.
Objective 2. Assess the effectiveness of newly developed and existing conservation practices that reduce the risk of agricultural contaminant losses that negatively affect water quality.
Subobjective 2.1. Identify, develop, and evaluate manure, fertilizer, tillage, irrigation, drainage, and nutrient management practices that improve production use efficiency and minimize off-site transfers.
Subobjective 2.2. Develop new technologies and management practices that improve and protect soil health.
Sub-Objective 2.3. Modernizing soil testing to optimize agricultural and environmental priorities and achieve precision management.
Objective 3: Develop management strategies and practices that conserve water resources and enhance agroecosystem services of wetlands cultivated for cranberry production.
Subobjective 3.1. Characterize soil carbon dynamics and temporal and spatial patterns of nutrient discharge from cranberry farms.
Subobjective 3.2. Develop new technologies and management practices that enhance water use efficiency and improve water quality on cranberry farms.
Objective 4 . In support of LTAR network goals, design sustainable agricultural systems that balance production, environmental, and rural prosperity objectives under changing agricultural and climatic conditions in the northeastern U.S.
Approach
Research spans the Chesapeake Bay and Buzzards Bay watersheds, relying upon core sites in the Atlantic Coastal Plain (Manokin watershed, MD; Buzzards Bay watershed, MA), Appalachian Piedmont (Conewago watershed, PA), and Appalachian Ridge and Valley (Mahantango Creek watershed, PA and Spruce Creek watershed, PA). The scope of our research encompasses entire agroecosystems and the supporting industrial complex. The water quality emphasis is primarily on controlling nutrient (N and P) loss to the environment. Increasingly, our research addresses carbon as related to climate change mitigation and adaptation. In the Upper Chesapeake Bay, we focus primarily on dairy production, the most common production system in the watershed. Similarly, our Congressionally mandated work on cranberry production (Objective 3) focuses on cranberry production enterprises and related externalities in the Buzzard Bay watershed. The private enterprise is at the center of our work because the individual producer is a key decision maker. Research activities represent targets of opportunity as identified by scientists and/or stakeholders or are in response to external funding opportunities that have been prioritized by funding agencies and that leverage internal resources and university partnerships. As a member of the LTAR network, outcomes have relevance to other agroecosystems and outcomes from research by other members of the network have relevance to our region. Linkages between our research activities and those of the other 19 LTAR research programs are too numerous to describe in detail, but collectively, outcomes from research across the network have greater potential for producing significant new, actionable knowledge for the dairy and cranberry industries than from our work alone.
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 core sites and a research infrastructure that enables measurement and chemical sampling of surface runoff, subsurface flow, and stream flow. We combine field observations with laboratory experiments that allow for greater control over indirect variables. Our basic research (Objective 1) involves observational and experimental studies, using parametric and nonparametric statistics as well as numerical models to quantify temporal and spatial dynamics or determine differences between management/land use, landscape units, and watershed components. Our applied research (Objectives 2-4) includes experimental studies, remote sensing, and modeling.
Progress Report
Team members on the Water Quality project continue to advance the research in the five-year project plan despite recent staff retirements and departures. Since research began in 2022, the project has encountered critical vacancies in several SY positions. For projects led by remaining staff, most of our 36-month milestones are on schedule, although progress on some Objectives was hindered due to external factors outside our control. In the sections that follow, we summarize our efforts to meet the 36-month milestones for the four main Objectives in the project plan.
Objective 1 of the project plan comprises four research projects that seek to illuminate the key processes driving pollutant fate and transport in agricultural watersheds. Overall, these projects remain on track, with only a few minor delays and modifications. For the groundwater age dating project, all age dating wells were instrumented with water level and conductivity sensors, and several rounds of routine water quality samples have been collected. Plans to sample the wells in spring of FY23 were thwarted due to a monthlong dry spell that left many of the wells too dry to sample. In fall of FY24, we were unable to sample the wells due to competing demands on other research projects. We currently plan to sample the age dating wells (as well as streams and riparian seeps) for age dating tracers in summer of FY24, and we expect to have results on groundwater residence times by fall/winter of FY25. The high-frequency nitrate sensing project is also on track, although we made some adjustments to our plans because the LTAR station on Little Conewago Creek was upgraded to a USGS super gauge location. This opportunity grew out of a multi-institutional collaboration focused on agricultural conservation and water quality outcomes in small agricultural watersheds. As such, we opted to maintain our scan nitrate sensors in the WE38 watershed so we could collect additional data in support of a peer-reviewed publication on event-scale nitrate concentration-discharge relationships. The paper is being led by a Penn State PhD student, and it will be readied by the end of FY24. The project using near-surface geophysics to examine critical source areas of subsurface phosphorus loss remains on schedule. A Rutgers PhD student recently submitted a paper summarizing the results of an intensive sprinkling study wherein time-lapse electrical imaging was used to track the migration of a salt tracer that was injected into shallow groundwater. Additional papers from this project are under development, including a short communications paper on the utility of integrating field-scale geophysical surveys in nutrient management. Finally, we are leveraging a cooperative agreement with the University of Maryland Eastern Shore to advance the research on watershed-scale processes controlling urea losses from agricultural landscapes. This project was directed by the former lead scientist, who retired from ARS in 2023. Per the cooperative agreement, the collaborating faculty member at UMES is leading the routine watershed sampling efforts, while the current lead scientist has committed to assist with data analysis and publication development.
Objective 2 of the project plan features applied research that evaluates the efficacy of new and existing conservation practices for controlling pollutant losses from agriculture. Under Sub-objective 2.1, three projects focus on the newly developed MAnure PHosphorus EXtraction (MAPHEX) system for removing phosphorus from liquid dairy manures. The projects – which were proposed and administered by the former chemist – are on hold due to lack of in-house scientific capacity in the Water Quality project. Since the former chemist’s departure, no additional progress has been made on the MAPHEX research. Consequently, we expect to modify the project plan to reflect the fact that the milestones for these projects will not be met. Elsewhere under Sub-objective 2.1, the project examining the response of corn yield to Lysine fertilization is on schedule. Rate trials in the greenhouse and field-based studies have been completed as planned, and a manuscript summarizing some of the notable results of this work has been submitted to a peer-reviewed journal. Lastly, in partnership with the National Weather Service’s Middle Atlantic River Forecast Center, we are analyzing ensemble forecasts of surface runoff in the Mahantango Creek watershed using the Ensemble Verification System. Preliminary forecast verification results look promising, suggesting that probabilistic forecasts of surface runoff may provide more information on the confidence of surface runoff occurrence than deterministic forecasts, leading to more informed decision making in nutrient management. In FY25, we expect to use these results to inform SurPhos modeling of manure and fertilizer timing in a small subwatershed of Mahantango Creek. SurPhos modeling is expected begin in earnest in the spring of FY25.
Sub-objective 2.2 encompasses two projects that center on technologies and management practices to improve soil health. The first project under this objective is assessing the utility of amending low-yield croplands with manure (aka manure priming) on soil health and crop yields. The project remains on track. In year three of this project, researchers continue to assess the benefits of applying manure to low-fertility soils. In FY23, split-plot studies evaluating the advantages of additional manure amendments relative to controls were completed as planned. Results continue to indicate that manure priming confers added yield benefits relative to unfertilized soils, although the soil health benefits appear to be minimal. Results from these studies contribute to multi-location research that is supported by ARS’s Dairy Agroecosystems Workgroup (DAWG). The second project under Sub-objective 2.2 is evaluating how periodic tillage affects phosphorus redistribution in soils. The success of this project is contingent on the selection of experimental fields on four to six farms with more than 10 years of no-till management and periodic surface applications of manure. To date, the selection of fields has proved problematic, and therefore this project is behind schedule. Efforts to find suitable fields are ongoing. Researchers expect to have candidate fields identified by fall of FY25, with plot establishment, experimental treatments, and routine soil sampling commencing shortly thereafter.
Sub-objective 2.3 involves three projects that seek to modernize soil testing for precision agriculture. The projects – which were designed and led by the former Research Leader – are on hold due to lack of in-house scientific capacity in the Water Quality project. Since the former Research Leader’s departure, no progress has been made on the Fertilizer Recommendation System Tool (FRST). The same holds true for the other two projects under former Research Leader’s direction: precision management of phosphorus and high-resolution spatial soil function modeling. Unfortunately, the Water Quality project does not have alternate leaders for any of the three research projects under subobjective 2.3. As such, we expect to modify the project plan to reflect the fact that the milestones for these projects will not be met.
Objective 3 of the project plan is dedicated to research on the sustainability of cranberry agriculture in the Northeast. The research focuses on developing and testing management practices that conserve water resources and improve ecosystem services. Subobjective 3.1 consists of two projects: one that examines carbon sequestration among active, restored, and retired cranberry farms, and another that strives to measure and model nitrogen inputs to Buzzards Bay. The carbon sequestration research is largely on schedule. In FY23, carbon dioxide flux measurements continued as planned, and the data from these sampling campaigns are currently being processed and analyzed. For the nitrogen loading project, the 36-month milestone was not met. Researchers encountered numerous challenges with the development of stage-discharge relationships in the seven rivers that are part of the study; in part, this is due to tidal influences in these riverine systems. Consequently, the lack of continuous discharge data has delayed efforts to calibrate and validate a SWAT model for these sites. Additional discharge readings are planned for FY24 and FY25 in order to finalize stage-discharge relations for the seven sites. Under subobjective 3.2, research is evaluating new technologies and practices for cranberry management, including variable-rate irrigation systems and the use of aluminum sulfate (alum) as a phosphorus sorbing agent. The 36-month milestone for the variable-rate irrigation study was substantially met, although researchers made some minor adjustments to the research plan in light of preliminary soil moisture data that were analyzed in FY23. The tech transfer activity that proposed alum as a phosphorus sorbing agent in cranberry systems is likely to be modified based on stakeholder input. Feedback from the Cape Cod Cranberry Growers’ Association indicated minimal interest in using alum. Instead, growers expressed keen interest in the potential of tail water recovery systems to address water quality concerns in cranberry agriculture. As such, scientists plan to modify the project plan to reflect stakeholder preferences for research on the implementation of tailwater recovery systems. A peer-reviewed paper was recently published by scientists from the Cranberry Station showing the potential of this technology.
Objective 4 of the project plan contributes to the Long-Term Agroecosystem Research (LTAR) Croplands Common Experiment. We continue to support university collaborators at Penn State who work closely with scientists in the Water Quality project and across the unit on allied research goals related to LTAR.
Accomplishments
1. Genetics, environment, and management in cranberry production. Hybrid cranberry cultivars offer an opportunity to produce more fruit with fewer resources, as ‘Stevens’, a first-generation hybrid cultivar, produces roughly twice as much fruit as the native cultivar ‘Early Black’. However, growers have expressed concern that genetic contamination may be linked to low crop yields in ‘Stevens’ cranberry fields in both Massachusetts and Wisconsin. In this study, scientists from three ARS units (University Park, Pennsylvania; East Wareham, Massachusetts; and Madison, Wisconsin) teamed up with researchers from the University of Massachusetts-Amherst to evaluate the effects of genotype and edaphic environment on crop yields in six ‘Stevens’ cranberry fields in Massachusetts. Genetic contamination, ranging from 38-75% impurity, was the most significant factor affecting crop yields in ‘Stevens’ fields. Among experimental plots confirmed to be pure ‘Stevens’, phenotypic variability, possibly derived from environmental variation, contributed to similar or even greater yield declines as genetic contamination. These findings highlight the need for more detailed investigation on the interactions between genetics, environment, and management in cranberry production.
Review Publications
Soder, K.J., Dell, C.J., Adler, P.R., Laboski, C.A., Williamson, B. 2024. The LTAR Common Experiment at Upper Chesapeake Bay: Integrated. Journal of Environmental Quality. 1-7. https://doi.org/10.1002/jeq2.20591.
Che, Y., Rejesus, R.M., Cavigelli, M.A., White, K.E., Aglasan, S., Knight, L.G., Dell, C.J., Holllinger, D., Lane, E. 2023. Long-term economic impacts of no-till adoption. Soil Security. http://doi.org/10.1016/j.soisec.2023.100103.
Kennedy, C.D., Omer, A., Wiegman, A.R., Welsh, M.K., Millar, D.J., Buda, A.R. 2024. Tailwater recovery systems can improve water quality: an area ripe for research in cranberry agriculture. Agricultural and Environmental Letters. 9(1):e20122. https://doi.org/10.1002/ael2.20122.
Millar, D.J., Kennedy, C.D., Zalapa, J.E., Jeranyama, P., Mupambi, G., Wiegman, A.R., Buda, A.R. 2024. Impacts of genotype, edaphic factors, and plant nutrients on yield and fruit quality for a perennial specialty crop (Vaccinium macrocarpon Ait.). Crop Science. 64(4):2231-2242. https://doi.org/10.1002/csc2.21272.
