Location: Pasture Systems & Watershed Management Research
2023 Annual Report
Objectives
Objective 1: Assess and improve sustainable intensification strategies of crop and integrated crop-livestock systems for farm systems, watersheds, and landscapes.
Sub-objective 1A: Quantify long-term sustainabilities of “business as usual” (BAU) and “aspirational” (ASP) dairy and beef production systems through farm simulation and life cycle assessment.
Sub-objective 1B: Develop management and placement strategies for improving ecosystem service provisioning through diverse agricultural landscapes that integrate crop and livestock systems.
Objective 2: Determine the sensitivity of farm systems, watersheds, and landscapes to climate variability and develop strategies for adapting agriculture to current and projected changes.
Sub-objective 2A: Quantify effects of projected climate and potential adaptation strategies on long-term sustainabilities of “business as usual” (BAU) and “aspirational” (ASP) dairy and beef production systems through the use of farm simulation and life cycle assessment.
Sub-objective 2B: Characterize the landscape-scale responses and trade-offs of agricultural ecosystem services, given projected climate and potential adaptation scenarios.
Approach
Agriculture faces increasing demands for productivity and efficiency that must be balanced against pressures to continually improve stewardship of natural resources. Climate models from 1950 through 2100 predict increases in temperature and precipitation in the Northeast, further complicating agricultural sustainability planning. Our research focuses on whole farms, watersheds, and landscapes to quantitatively evaluate both long-term sustainabilities and broader environmental impacts of various agricultural production systems under current and predicted climate. We will evaluate alternative production strategies based on economic viability, implementation feasibility, and impacts to ecosystem services and disservices. We are concerned with not only provisioning ecosystem services such as dairy, beef, and crop production but also supporting and regulating services like nutrient cycling and landscape diversity. Disservices from agriculture include greenhouse gas emissions and other nutrient losses to air and water.
Our two objectives assess “business as usual” (BAU) and “aspirational” (ASP) agricultural production strategies for sustainable intensification at multiple scales. The (A) sub-objectives are farm-scale in detail and industry-wide in scope. The (B) sub-objectives focus on landscape-scale hydrology and ecology within the Northeast to inform both local and multi-regional research efforts. Objective 1 assesses strategies under recent climate conditions (1980-2005), and corroborates our modeling tools in representing BAU and ASP strategies. To be most valuable, however, developed strategies and tools must be successful under future climate conditions. Objective 2 corroborates our tools under historical climate (1960-1980) and applies them under future mid-century (2040-2060) and late-century (2080-2100) climate projections, assessing ASP strategies that most effectively meet the challenges and opportunities of future climate.
We will collaborate with larger USDA-led research networks, including the Long-Term Agroecological Research network (LTAR), Conservation Effects Assessment Project (CEAP), and Dairy Agroecosystems Working Group (DAWG). Such networking provides expertise and data on outcomes from management strategies for cropping and integrated crop-livestock systems that will be used to confirm results of the first objective and provide a basis for extrapolation of future systems for the second. We will analyze data using both simple and complex process-based simulation models, life cycle assessment, and advanced computational techniques.
With an emphasis on sustainable intensification in accord with climate predictions, our research will support systems-level understandings of current and potential agricultural systems in the Northeast, and how these can continue to produce food and fuel in the future. Outcomes of this research will support farmers directly through management strategies and decision support tools, and will provide scientifically-valid data to federal and state programs aimed at improving nutrient management, conservation, and resource use efficiency.
Progress Report
In Sub-Objective 1.A, National Life Cycle Assessments (LCA) of dairy and beef cattle production in the U.S. were completed, providing baselines for comparison to future assessments and the evaluation of mitigation strategies. Average annual greenhouse gas emissions, reactive nitrogen losses, fossil energy use, and blue water consumption were determined and compared to reported national inventories. The beef cattle production data were also combined with packing, processing, marketing, consumption, and waste handling data to produce a cradle to grave LCA of multiple environmental impact categories using an integration of IFSM and Open LCA software systems. Perhaps the greatest concern of all environmental impacts for both dairy and beef systems is that of ammonia emissions; these industries combined may emit about half the total ammonia emissions estimated to be coming from the nation. Freshwater consumption is also an important concern for future sustainability of these industries, particularly in the dry western regions.
Production systems using desert adapted Rarámuri Criollo cattle and crossbreds of Criollo with Angus cattle were studied to determine potential environmental and economic benefits compared to the traditional Angus cattle production systems currently used in the arid southwest region. Crossbred cattle production with grass finishing in the Southwest or in the Northern Plains outperformed on most environmental variables with lower production costs but this option emitted more greenhouse gas than grain finishing of Angus cattle in the region. As the climate in the southwest region becomes drier in the future, use of Criollo cattle and their crossbreds can provide more sustainable cattle production systems for producing food in this region.
A comprehensive assessment was completed on the environmental sustainability of grass-based dairy farms in Pennsylvania. We found that this production strategy can provide environmental benefits to a local watershed, but due to a lower efficiency in milk production compared to larger confinement farms, this strategy increases the aggregate environmental impacts of regional and global supply chains. Using a cover crop, interseeded grass crop, or small grain double crop with corn production on Pennsylvania dairy farms provided reductions in sediment, nitrogen, and phosphorus losses. Benefits varied across the different management approaches used on farms, with interseeding of annual grass in the growing corn crop providing the greatest reduction. Only double cropping small grain silage with corn silage increased feed production sufficiently to provide economic benefit to the farm. Use of a decanter centrifuge to extract phosphorus from manure on a Pennsylvania dairy farm provided a better ratio of nitrogen and phosphorus contents for use on nearby cropland and reduced transport costs for nutrients applied to more distant cropland.
In Sub-Objective 1.B, simulation models and economic assessments were conducted at the crop, farm, and watershed scale to explore system-wide impacts of sustainable intensification on ecosystem services in northeastern U.S. Results demonstrated the importance of best management practice planning at the local level to address both local and regional concerns within the Chesapeake Bay catchment. High-risk landscape characteristics predicted by the Agricultural Conservation Planning Framework (ACPF) were ground-truthed and overlain with high-risk areas predicted by the Soil and Water Assessment Tool (SWAT). Results drove prioritization guidelines for cost-effective, watershed-level, management practice implementation. Additionally, by focusing on hillslope position and topography while simulating infiltration- and saturation-based flows, continuous water-quality modeling of multi-year rotations was used to evaluate and modify Pennsylvania Phosphorus Index version 2. This work fed into a national effort between ARS and Natural Resources Conservation Service (NRCS) to identify and upgrade tools for conservation planners to organize their mitigation outreach efforts based on local geospatial information and water quality modeling.
Spatial historical life cycle models were developed for corn and soybeans from NASS crop pesticide life cycle inventory (LCI) data where impact was characterized using the CLiCC Chemical Life Cycle Collaborative Tool and the effectiveness of mitigation practice effectiveness was evaluated.
A suite of tools was developed for modeling crucial aspects of agricultural systems, focusing on erosion and pasture production in the northeastern United States, and how climate, soils, and management options interact to determine environmental outcomes. These models were integrated into an automated and reproducible workflow to facilitate regional and national modeling, and to enable the use of SCINet resources. Complementary work on plant phenology across the eastern United States was developed to allow the incorporation of non-agricultural vegetation into the quantification of pollinator resources on agricultural landscapes. Scientists are working with university partners to incorporate findings into existing online decision support tools, and with NRCS to incorporate research findings into a novel online tool for assessing pasture conservation needs based on environmental factors and management.
In Sub-Objective 2.A, adoption of farm-specific beneficial management practices was found to substantially reduce greenhouse gas emissions and nutrient losses from dairy farms in the northeastern U.S. under current climate and stabilize the environmental impact in future climate conditions. Thus, appropriate management changes can help dairy farms become more sustainable under current climate and better prepared to adapt to future climate variability.
Crop response to increasing atmospheric carbon dioxide was predicted by the Integrated Farm System Model (IFSM) within the ranges measured in free-air carbon dioxide enrichment (FACE) experiments for grain yield, total biomass yield and harvest index. Following this verification, IFSM was used to evaluate the effect of increasing carbon dioxide and changing climate on double crop corn and rye silage systems on dairy farms in central Pennsylvania. We found that double cropping benefited greatly from the projected increase in growing season length providing additional forage that is less susceptible to summer droughts. Use of this more intensive crop rotation along with improved manure application technology can help mitigate dairy farm environmental impacts now and even more in the future without significantly increasing total production costs.
The IFSM was also verified to represent the performance and nutrient losses of corn production in the Northern Plains region using different manure and inorganic fertilization treatments. Following verification, simulated beef finishing systems showed greater ammonia emission and soluble P runoff with use of feedlot and bedded manure compared to use of inorganic fertilizers, but life-cycle fossil energy use and greenhouse gas emission were decreased. Projected climate change by mid-century gave a small increase in feed production in the Dakotas and a small decrease for irrigated corn in Nebraska. Environmental impact differences among the fertilization systems under future climate were generally like those obtained under recent climate.
Under Sub-Objective 2.B, cropping rotations were spatially reallocated across a piedmont agricultural watershed to explore the potential for more optimized use of the regions physiographic features in mitigating long-term production-reducing changes in climate. These findings stress the importance of informed design and implementation of best management practices effective in "hot moments" and not just "hot spots" across impaired watersheds to achieve and maintain water quality restoration goals. The "temporal targeting framework" provides a useful and convenient method for watershed planners to create low- and high-flow load targeting tables specific to a watershed and constituent.
The Soil and Water Assessment Tool was modified to include dynamic carbon dioxide input and account for the resulting impacts to evapotranspiration. After corroboration, the modified version was used to simulate and compare three northeastern Long-Term Agroecosystem Research watersheds under nine climate forecasts to determine early-, mid-, and late-century predictions of agricultural water quantity and quality. Additionally, the long-term practicality of promoting a shift in manure application levels to not exceed agronomic phosphorus demands was simulated across the Susquehanna River Basin with several variations. Results demonstrated the potential water quality benefit of moving excess manure away from the intense agricultural systems and toward the headwaters.
The modeling workflow developed in subobjective 1.B with current climate data was repeated using climate change projections. Species distribution and phenological models developed using machine learning methods added the capacity to better understand potential shifts in forage and crop species potential ranges. Pollinator resources were added explicitly using improved land cover maps and phenological models. This fusion resulted in maps of potential future agricultural scenarios for the northeastern United States, and consequences for ecosystem services including production, soil erosion, and pollination services. Scientists are working with university partners to incorporate findings into existing online decision support tools.
Accomplishments
1. Beneficial reuse of treated wastewater. Beneficial reuse of treated wastewater as an irrigation source is becoming increasingly widespread to reduce reliance on freshwater resource for agricultural production. However, emerging contaminants, such as pharmaceuticals and personal care products (PPCPs) and per- and polyfluoroalkyl substances (PFAS) are inadvertently introduced into agricultural fields when treated wastewater is used for irrigation due to their persistence through conventional wastewater treatment technologies. The Pennsylvania State University main campus has its own water reclamation facility that treats all campus wastewater for beneficial reuse at a mixed-use (agricultural and forested) site known as the “Living Filter”. The facility has been operating at full-scale for more than 40 years. To understand the long-term benefits and potential impacts of beneficial reuse of treated wastewater for irrigation, ARS scientists at University Park, Pennsylvania, and Penn State University collaborators monitored the occurrence of PPCPs and PFAS in the wastewater influent, effluent, and 13 groundwater monitoring stations at the site. The results showed that the Living Filter, with soil profiles exceeding 100 ft in some portions of the site, provides a significant benefit to mitigating PPCPs prior to the water reaching the groundwater, with concentrations up to two orders of magnitude lower in the groundwater compared to the wastewater effluent. However, the results for PFAS suggested that although the site was protecting nearby surface water (i.e., the treatment facility does not discharge to the local stream – Spring Creek – which is a high-quality cold-water fishery), it is unable to reduce the PFAS concentrations to below the state (passed) and federal (proposed) drinking water standards. Therefore, our results reveal concerns for long-term usage of treated wastewater as an irrigation source if PFAS remain in elevated levels in the treated effluent.
2. Enhancing spatial targeting with temporal targeting. Implementation of agricultural best management practices over the past decade have often failed to meet load reduction goals in the Chesapeake Bay watershed. To better understand why water quality goals lag adoption of agricultural conservation practices, ARS scientists at University Park, Pennsylvania, and Penn State University collaborators leveraged a technique called Lorenz Inequality that is commonly used in economics to quantify income inequality. Using this technique, scientists quantified the degree of temporal inequality exhibited by sediment and nutrient loads for catchments across the Bay watershed and found that a large majority of annual loads are transported during short periods of time associated with high-flow events. Conservation practices are often most effective during smaller events; therefore, this approach provided insight into the periods of time when loads could most effectively be targeted from a temporal perspective, enhancing the spatial targeting approach that most watershed implementation plans utilize. This approach was applied to a wide range of water quality parameters in a Long-term Agroecosystem Research watershed to demonstrate that conservation practices implemented there were effective in preventing legacy phosphorus buildup. Finally, this approach was used to develop a decision-making tool to identify the “windows of opportunity” that could be targeted to achieve load reduction goals most effectively. By better understanding the temporal variability of nutrient and sediment loads, solutions can be proposed that enable targeting to move from the “right practice in the right place” to the “right practice in the right place at the right time”. Three peer-reviewed manuscripts provide the data analysis and decision-making tools necessary for enhancing spatial targeting of conservation practices to include a temporal targeting component.
3. Environmental sustainability of United States beef. There is increasing public awareness and concern regarding the environmental effects of agriculture with particular interest in beef production. A full life cycle assessment of U.S. beef was conducted to determine total impacts from the production of resources used through consumption and the waste created for a comprehensive set of environmental impact categories. In most categories, the major sources of impact were related to cattle production. For other categories, electricity consumption across the supply chain was a substantial driver of environmental impacts. Food waste was a major contributor to all categories making waste among the greatest impacts on the environmental sustainability of U.S. beef. This highlights the importance of engaging the full supply chain in understanding the impacts of the industry. This assessment of U.S. beef provides a baseline to quantify potential national benefits as mitigation strategies are developed and implemented.
4. Reducing concentrated flow pathways to improve stream buffers. Riparian buffers are a widespread agricultural conservation practice in the Chesapeake Bay watershed because they are considered among the most effective in trapping nutrients and sediment prior in stormwater runoff prior to reaching adjacent streams. However, the prevalence of concentrated flow pathways has caused concerns, as these pathways cause stormwater to be “short-circuited” through these buffers, reducing their potential to mitigate pollutants. Stream segments assessed before and after buffer implementation did not show consistent improvement in macroinvertebrate diversity, which poses challenges for de-listing these streams from the impaired list. Implementation of buffers does not necessarily address in-stream issues for macroinvertebrate habitat, and modeling efforts to simulate the benefits of riparian buffer adoption do not include maintenance issues, such as erosional pathways, that may be compromising buffer integrity. Recent research by ARS scientists from University Park, Pennsylvania, and collaborators demonstrated that the occurrence of concentrated flow pathways can undermine the effectiveness of riparian buffers not only for sediment and nutrient treatment, but also for pesticides. Additionally, multi-zone buffers, with grass between the crops and forested section of a buffer, help to improve buffer effectiveness and reduce the potential for concentrated flow pathways to form. If pesticides are short-circuited through buffer zones, then this provides further pressure on macroinvertebrates, and may be contributing to a lack of correlation between buffer implementation and improved diversity (e.g., Index of Biotic Integrity scores). Findings suggest that more efforts are needed to ensure buffers are properly maintained following adoption to keep their integrity from being compromised due to erosional issues.
5. Stakeholder engagement improves watershed management planning. Including stakeholder preferences in the development of watershed management plans is critically important to the successful restoration of an impaired waterway. However, how their preferences are included in the development of these plans remains inconsistent. For example, hydrology and water quality models can produce a suite of possible adoption options that all achieve the same water quality goal. If scientists set up scenarios before engaging with stakeholders, then the results are likely to not meet stakeholder needs and will likely fail to be implemented. If instead, stakeholders are involved prior to model development, then the scenarios that are run using the model will reflect stakeholder preferences and are more likely to be well-received by local landowners. Through a collection of four peer-reviewed papers, ARS scientists at University Park, Pennsylvania, and collaborators provide several examples of successful engagement with local stakeholders that resulted in watershed management plans that reflected stakeholder inputs/values and achieved nutrient and sediment load reduction goals. These goals were achieved in several ways, depending on the case study watershed; either prioritizing lowest cost of implementing the plan at the watershed scale while meeting load reduction goals or prioritizing yield across the watershed by modifying where in the watershed crops were grown (functional land management approach). The collection of papers provides examples of stakeholder engagement processes that were successful in development of each management plan, as well as documented the water quality benefits of those plans compared to other more traditional approaches that do not take stakeholder preferences into consideration. In each case study, water quality goals were achieved or exceeded using by incorporating stakeholder engagement into computer-based approaches.
6. Bio-char more sustainably treats wastewater. Conventional wastewater treatment plants are unable to effectively degrade or remove emerging contaminants, including pharmaceuticals, such that these chemicals persist in the effluent. They are therefore inadvertently introduced into streams during discharge or to agricultural fields if the treated wastewater is reused as an irrigation source. However, technologies that effectively remove these pharmaceuticals, such as ion exchange resin or activated carbon, are expensive and can be energy intensive to produce and/or operate. Therefore, low-cost and low-energy solutions are needed to improve the sustainability of providing further treatment to wastewater. ARS scientists at University Park, Pennsylvania, have been exploring the potential for biochar produced from agricultural waste products, including guayule bagasse, cotton gin, and walnut shells, to act as a sorbent for removing pharmaceuticals from water. Biochar from cotton gin outperformed biochar from guyule bagasse. Biochar derived from cotton gin waste adsorbed 98% of the docusate, 74% of the erythromycin and 70% of the sulfapyridine in aqueous solution. By comparison, the biochar derived from guayule bagasse adsorbed 50% of the docusate, 50% of the erythromycin and just 5% of the sulfapyridine. However, biochar from walnut shells performed best at removing sulfapyridine and acetaminophen, with 72% and 68% removal of each, respectively, after 24 hours. Our results show that additional research is needed to better develop “designer biochars” to best achieve specific water quality goals. In addition, design parameters and operating conditions for biochar-based systems are still lacking. Overall, our findings suggest that future research should focus on developing and validating protocols for biochar production and design of biochar water treatment technologies.
Review Publications
Mercier, K.M., Billman, E.D., Soder, K.J., Jaramillo, D.M., Goslee, S.C., Adler, P.R. 2023. Managing interspecies competition to improve spring pasture maturity, nutritive value, and biomass. Crop Science. 63(2):974–986. https://doi.org/10.1002/csc2.20892.
McDowell, R., Rotz, C.A., Oenema, J., Maclntosh, K. 2022. Limiting grazing periods combined with proper housing can reduce nutrient losses from dairy systems. Nature Food. 3:1065-1074. https://doi.org/10.1038/s43016-022-00644-2.
Spiegal, S.A., Vendramini, J.M., Bittman, S., Silveira, M., Gifford, C., Ragosta, J.P., Kleinman, P.J. 2022. Recycling nutrients in the beef supply chain through circular manuresheds: Data to assess tradeoffs. Journal of Environmental Quality. 51(4):494-509. https://doi.org/10.1002/jeq2.20365.
Goodrich, D.C., Bosch, D.D., Bryant, R.B., Cosh, M.H., Endale, D.M., Veith, T.L., Kleinman, P.J., Langendoen, E.J., McCarty, G.W., Pierson Jr., F.B., Schomberg, H.H., Smith, D.R., Starks, P.J., Strickland, T.C., Tsegaye, T.D., Awada, T., Swain, H., Derner, J.D., Bestelmeyer, B.T., Schmer, M.R., Baker, J.M., Carlson, B.R., Huggins, D.R., Archer, D.W., Armendariz, G.A. 2022. Long term agroecosystem research experimental watershed network. Hydrological Processes. 36(3). Article e14534. https://doi.org/10.1002/hyp.14534. [Corrigendum: Hydrological Processes: 2022, 36(6), Article e14609. https://doi.org/10.1002/hyp.14609.]
Phung, Q., Thompson, A., Baffaut, C., Witthaus, L.M., Aloysius, N., Veith, T.L., Bosch, D.D., McCarty, G.W., Lee, S. 2023. Assessing soil vulnerability index classification with respect to rainfall characteristics. Journal of Soil and Water Conservation. 78(3):209-221. https://doi.org/10.2489/jswc.2023.00065.
Hayden, K.R., Jones, M., Elkin, K.R., Shreve, M.J., Clees II, W.I., Clark, S., Mashtare, M.L., Veith, T.L., Elliott, H.A., Watson, J.E., Silverman, J., Richard, T.L., Read, A.F., Preisendanz, H.E. 2022. Impacts of the COVID-19 pandemic on pharmaceuticals in wastewater treated for beneficial reuse: Two case studies in central Pennsylvania. Journal of Environmental Quality. 51(5):1066–1082. https://doi.org/10.1002/jeq2.20398.
Mroczko, O., Preisendanz, H.E., Wilson, C., Elliott, H.A., Veith, T.L., Mashtare, M.L., Soder, K.J., Watson, J.E. 2022. Spatiotemporal patterns of PFAS in water and crop tissue at a beneficial wastewater reuse site in central Pennsylvania. Science of the Total Environment. 51(6):1282–1297. https://doi.org/10.1002/jeq2.20408.
Putman, B., Rotz, C.A., Thoma, G. 2023. A comprehensive environmental assessment of beef production and consumption in the United States. Journal of Cleaner Production. 402:136766. https://doi.org/10.1016/j.jclepro.2023.136766.
Thivierge, M., Belanger, G., Jego, G., Delmotte, S., Rotz, C.A., Charbonneau, E. 2023. Perennial forages in cold-humid areas: Adaptation and resilience-building strategies towards climate change. Agronomy Journal. 115(4):1519-1542. https://doi.org/10.1002/agj2.21354.
Saha, A., Cibin, R., Veith, T.L., White, C.M., Drohan, P.J. 2023. Water quality benefits of weather-based manure application timing and manure placement strategies. Journal of Environmental Management. 333:117386. https://doi.org/10.1016/j.jenvman.2023.117386.
Chiles, R.M., Drohan, P.J., Cibin, R., O'Sullivan, L., Doody, D., Schulte, R., Grady, C., Jiang, F., Preisendanz, H.E., Dingkuhn, E.L., Veith, T.L., Anderson, A. 2023. Optimization and reflexivity in interdisciplinary agri-environmental scholarship. Frontiers in Sustainable Food Systems. 7:1083388. https://doi.org/10.3389/fsufs.2023.1083388.
