Location: Pasture Systems & Watershed Management Research
2019 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
Progress was made on both objectives and their subobjectives, all of which fall under National Program Action Plan 216: Agricultural System Competitiveness and Sustainability and contributes to Component 1: Building agroecosystems for intensive, resilient production via GxExM; Component 2: Increasing efficiency of agroecosystems; and Component 3: Reaching agroecosystem potentials.
Under Objective 1, Subobjective 1A, a national Life Cycle Assessment (LCA) of beef cattle production was completed providing important environmental impacts of beef cattle in the U.S. Average annual greenhouse gas emissions, reactive nitrogen (N) losses, fossil energy use and blue water consumption associated with beef cattle production were determined and compared to other reported sources for the U.S. These data provide a baseline for comparison to future assessments and the evaluation of potential benefits of mitigation strategies. This also provides information to support a complete life cycle assessment of beef including packing, processing, marketing, consumption and waste handling. A methodology was developed and used to assess important environmental footprints of dairy farms for the state of Pennsylvania using process-level simulation and cradle to farm-gate life cycle assessment. State level impacts and intensities were determined for greenhouse gas emissions, reactive nitrogen losses, fossil energy use and non-precipitation water consumption. From these metrics, dairy farms represented 1.6% of the greenhouse gas emissions, 0.3% of fossil energy use and 0.6% of fresh water consumption reported for the state. Perhaps the greatest concern of all environmental impacts is that of ammonia emissions where dairy farms were found to emit about half that estimated to be coming from the state. Additionally, a simulation analysis of beef cattle systems in New Mexico was completed comparing performance and environmental footprints for wet and dry climate years. Compared to wet years, dry years provided slightly lower greenhouse gas emission, slightly lower energy use, greater reactive nitrogen loss and much greater water consumption per unit of beef produced.
Under Objective 1, Subobjective 1B, simulation models and economic assessments were conducted at the crop, farm, and watershed scale to begin exploring system-wide impacts of sustainable intensification on ecosystem services in northeastern U.S. Watershed-level water quality simulation scenarios were created and corroborated for three Long-term Agroecosystem Research (LTAR) watersheds in Pennsylvania (Spring Creek, Conewago, and Mahantango) using Topo-SWAT, which is a variation of the Soil and Water Assessment Tool hydrologic water quality model that accounts for variable source hydrology. Scenarios created included current management baselines, representation of the Watershed Implementation Plan suggestions for each watershed, and “Smarter” placement of the Watershed Implementation Plan practices designed to provide more cost-effective watershed-wide pollution reduction. A manuscript comparing the efficiencies of management practices simulated for Spring Creek, and the potentials of those practices to contribute toward state total maximum daily load (TMDL) goals, is currently under journal review. At the farm level, an assessment of crop intensification on farm net income was completed. Crop intensification had a negative impact on net returns in Pennsylvania, but was generally neutral to positive from Maryland south to North Carolina. Although positive, incorporating payment for ecosystem services (PES) did not have a large impact on net return. When crop residues were not harvested, carbon sequestration was the largest component of PES. However, when crop residues were harvested, carbon sequestration values were more similar to leached nitrate values, while nitrous oxide was much lower. Due to nitrogen fertilizer costs, winter rye was never profitable and was always less profitable than other double crop options. Winter barley was closer to overcoming hurdle rates since it has less impact on soybean yields than winter wheat north of the 40th parallel. Given current PES payment levels, the addition of local markets for winter crop residue are crucial to incentivizing double cropping. Establishment of a bioenergy or pulp market for biomass would likely provide such a market and could potentially incentivize widespread planting of winter barley as a double crop in corn-soybean rotations. At the crop level, the Light Interception and Utilization Simulator (LINTUL3) and the World Food Studies (WOFOST) process-based crop production models, both extensively used in Europe and the United States, were parameterized for the common forage species orchardgrass, perennial ryegrass, and white clover, and validated against existing forage production datasets. These models are being used to improve understanding of potential forage production capacity in the northeastern U.S. under climate change scenarios.
Under Objective 2, Subobjective 2A, a comprehensive assessment of the effects of climate change on the environmental performance and productivity of typical dairy farms in the northeastern U.S. was completed along with an evaluation of strategies for adapting to climate change. Adoption of farm-specific beneficial management practices were found to substantially reduce greenhouse gas emissions and nutrient losses from the farms under current climate conditions and stabilize the environmental impact in future climate conditions. Thus, appropriate management changes can help our dairy farms become more sustainable under current climate and better prepared to adapt to future climate variability.
Under Objective 2, Subobjective 2B, the recent version of SWAT was modified to include dynamic carbon dioxide input and account for the resulting impacts to evapotranspiration. The modified version was corroborated using climatic trends from a set of climate projection models for the Pennsylvania Long-Term Agroecosystem Research (LTAR) watersheds. Additionally, consistent spatial and temporal datasets for soils, climate, and topography for the continental U.S. are required for multiple projects including the USDA LTAR, NRCS National Resources Inventory (NRI), and NRCS Conservation Effects Assessment Project (CEAP), and for forage suitability group development. Considerable effort has been devoted to identifying and calculating derived metrics related to the plant requirements of light, temperature, and water, including climate indices relevant to plant growth, including the BIOCLIM and CLIMDEX metrics, and the metrics proposed in the NRCS Range and Pasture Handbook. Pollinator-specific indices have also been developed and tested against Pennsylvania apiary survival data, thus improving the representation of agriculturally-important ecosystem services, as well as providing valuable information to beekeepers. Indices have been calculated for both current and predicted future climates. Derived topographic variables including slope, aspect, curvature, and topographic convergence have been calculated from the 30m National Elevation Dataset for the continental U.S., and supplemented with both Cropland Data Layer and National Land Cover Data for 2008-2018. Digital soils mapping products at several scales complement standard soils products.
Accomplishments
1. A national assessment of U.S. beef cattle production. The U.S. beef industry is a major contributor to the national and global food system and economy with a potential for increasing production to feed the growing domestic population while meeting expanding export markets. Increasing productivity in an environmentally, economically, and socially sustainable manner is of concern to both producers and consumers. Our cattle production systems are very complex with many components and interactions, so quantifying and measuring sustainability is challenging. Through a comprehensive national assessment, ARS scientists at University Park, Pennsylvania in collaboration with the National Cattlemen’s Beef Association found beef cattle production emitted 3.3% of greenhouse house emissions, produced 15% of reactive nitrogen losses, used 0.7% of fossil energy and consumed 5.8% of fresh water when compared to current estimates for the nation. These data provide a baseline for comparison to future assessments and the evaluation of potential benefits of mitigation strategies.
2. USDA’s Conservation Reserve Program (CRP) improves water quality of Chesapeake Bay. USDA’s Conservation Reserve Program (CRP) is the nation’s flagship private-land conservation program and has played a critical role in state and federal efforts to improve the health of the Chesapeaking Bay. In the six states contributing to the Chesapeake Bay watershed, CRP has funded over 20,000 riparian (stream area) buffer contracts. To evaluate the performance of riparian buffers in the Chesapeake Bay watershed, a “One-USDA” project was implemented (USDA’s ARS, FSA, NRCS, FS) with support from a broader consortium of researchers that included scientists from U.S. Geological Survey and Penn State. They found that riparian forested buffers reduce nitrogen pollution by 17 to 56%, and phosphorus pollution by 4 to 20%, while riparian grass buffers were roughly equally effective. However, filtration of runoff by riparian buffers is regularly undermined by gullies and ditches that route runoff water around buffers, reducing the potential for buffers to treat runoff from adjacent lands by an average of 37% across the study area. Findings point to the need to bundle conservation practices, and programs, to optimize the performance of riparian buffers.
Review Publications
Adler, P.R., Hums, M., Mcneal, F.M., Spatari, S. 2018. Evaluation of environmental and cost tradeoffs of producing energy from soybeans for on-farm use. Journal of Cleaner Production. 210:1635-1649. https://doi.org/10.1016/j.jclepro.2018.11.019.
Cordeiro, M.R., Rotz, C.A., Kroebel, R., Beauchemin, K., Hunt, D., Bittman, S., Koenig, K.M., McKenzie, D.B. 2019. Prospects of increased dairy farm forage production under climate and land-use changes in Newfoundland, Canada. Agronomy. 9(1):2-20. https://doi.org/10.3390/agronomy9010031.
Gunn, K.M., Holly, M.A., Veith, T.L., Buda, A.R., Prasad, R., Rotz, C.A., Soder, K.J., Stoner, A. 2019. Projected heat stress challenges and abatement opportunities for U.S. milk production. PLoS One. 14(3):1-21. https://doi.org/10.1371/journal.pone.0214665.
Holly, M.A., Gunn, K.M., Rotz, C.A., Kleinman, P.J. 2019. Dairy farming strategy and herd size effects on productivity, feed utilization, and manure management in Pennsylvania. Journal of Dairy Science. 35(3):325-338. https://doi.org/10.15232/aas.2018-01833.
Rau, B.M., Adler, P.R., Dell, C.J., Saha, D., Kemanian, A. 2019. Herbaceous perennial biomass production on frequently saturated marginal soils: Influence on N2O emissions and shallow groundwater. Biomass and Bioenergy. 122:90-98. https://doi.org/10.1016/j.biombioe.2019.01.023.
Rotz, C.A., Asem-Hiablie, S., Place, S., Thoma, G. 2018. Environmental footprints of beef cattle production in the United States. Agricultural Systems. 169:1-13. https://doi.org/10.1016/j.agsy.2018.11.005.
