Research Project: Developing, Evaluating, and Optimizing Diversified Agricultural Systems for a Changing Environment in the Mid-Atlantic Region

Location: Sustainable Agricultural Systems Laboratory

2024 Annual Report

Objectives
Objective 1: Improve quantification and accounting of fundamental ecosystem services delivered by diversified long-term grain and forage cropping systems, both organic and conventional, and explore mechanisms influencing ecosystem service provisioning. Sub-objective 1.A: Compare factors controlling crop performance in long-term organic and conventional cropping systems. Sub-objective 1.B: Evaluate soil function and ecosystem services in long-term organic and conventional cropping systems. Sub-objective 1.C: Quantify the impacts of cropping systems on geospatial distributions of soil microbial communities. Sub-objective 1.D Conduct integrated analyses to assess the impacts of cropping systems diversity on system performance and the provision of ecosystem services. Sub-objective 1.E. Test, validate, and parameterize MAIZSIM, GLYCIM, and anticipated wheat and rye CC models using long-term FSP datasets. Sub-objective 1.F: Compare factors controlling crop performance in long-term cover-crop based no-till systems. Objective 2: Develop new technologies and management strategies that improve system productivity, and resilience to changing climate and other system disruptions, and food safety and nutrition of diverse cropping and soilless systems. Sub-objective 2.A. Screen and improve grass and legume CCs for higher biomass, winter hardiness, soft seed, disease resistance, and allelopathy. Sub-objective 2.B. Aggregate data from a national on-farm research network to calibrate and validate a regional CC nitrogen calculator (CC-NCALC). Sub-objective 2.C. Improve CC performance mapping with multi-spectral and hyperspectral imagery. Sub-objective 2.D. Use a high-resolution, open-access plant image repository for CCs to train low-cost sensors for real-time, high-resolution mapping of CC species, quality, and biomass. Sub-objective 2.E. Construct web-based decision support tools that inform species selection, seeding rate recommendations, and economic assessments that are national in scope but site-specific in the application for CC management and the other 59 NRCS vegetation conservation management practices. Objective 3: Develop new technologies and management strategies that improve system productivity, food safety, and nutrition of soilless systems, and explore the microbial degradation of per- and polyfluoroalkyl substances (PFAS). Sub-objective 3.A. Develop validated methods to assess the presence of pathogens in recirculating hydroponic (HP) and aquaponic (AP) systems and the produce. Sub-objective 3.B. Determine the efficacy of physical and biological treatment technologies on pathogen control in HP and AP systems. Sub-objective 3.C. Screen and identify microorganisms and environments that enhance the degradation and reduce the half-life of per- and polyfluoroalkyl substances (PFAS).

Approach
Approaches to developing, evaluating, and optimizing diversified agricultural systems under Objective 1 include measuring crop yield, soil moisture, and carbon and nutrient dynamics at three Beltsville long-term field research projects: the Farming Systems Project, the Cover Crop Systems Project and the LTAR Lower Chesapeake Bay Cropland Common Experiment. In addition, efforts at FSP will also include measuring weed population dynamics, soil carbon fractions, greenhouse gas fluxes, soil microbiological community structure and function, and soybean nitrogen fixation, and conducting integrated analyses to evaluate overall systems performance. FSP data will also be used to test MAIZSIM and other crop growth models and will be used in long-term cross-location network analyses. Approaches under Objective 2 include 1) breeding and selecting cover crop varieties of hairy vetch, winter pea, crimson clover, and cereal rye through traditional, participatory, and marker-assisted methods; 2) calibrating the cover crop nitrogen calculator (CC-NCALC) for the Eastern US; 3) using multi-spectral imagery from satellites, combined with climate variables and plant growth models, to accurately estimate cover crop shoot biomass in the field; 4) collecting laboratory-based hyperspectral data to identify spectral regions most sensitive to cover crop characteristics and then examine how cover crop termination methods influence these spectral characteristics; and 5) constructing and publicly releasing, with NRCS, the Vegetation Planning Tool. Approaches under Objective 3 include 1) collecting samples from commercial and research-based aquaponics and hydroponics systems: water from all compartments, plant roots, and biofilter solids and analyzing samples for generic E. coli, Listeria spp., aerobic plate counts, microbiomes, and standard water quality parameters; 2) conducting inoculated challenge studies with phytopathogens and surrogate bacterial contaminants in non-commercial research aquaponics and hydroponics systems; 3) measuring pathogen control using nanobubble, plasma-activated water, UV light, and biocontrols separately or in combinations in recirculating aquaponics and hydroponics systems; and 4) identifying microorganisms and environments that enhance the degradation and reduce the half-life of PFAS.

Progress Report
In support of Objective 1 focused on long-term research conducted at the Farming Systems Project (FSP), the Lower Chesapeake Bay Common Experiment (LCB CCE), and within the DRIVES Network (Diverse Rotations Improve Valuable Ecosystem Services). Progress was made on all Sub-objectives. Five years of data on continuously monitored soil moisture content in FSP corn plots has been compiled 11 years of data on corn and soybean yields from variety microplots at FSP have largely been compiled and a draft manuscript has been written to address Hypothesis 1.A2. This manuscript shows that poultry litter application rate can be decreased by 50% (2-year organic rotation), 67% (3-year organic rotation) and 100% (6-year organic rotation) without impacting corn grain yield, thus improving phosphorus balances in the 2-year and 3-year rotations. Data on nitrous oxide emissions from the microplots used for Hypothesis 1.A2 show that emissions of nitrous oxide, an important greenhouse gas, can be reduced by 27% to 59% at optimal poultry litter application rates. Soil samples archived from these microplots are being used by a University of Maryland graduate student to quantify the impact of poultry litter applications on formation, persistence, and turnover of soil organic matter fractions that impact plant available nitrogen and soil carbon sequestration. The student is measuring soil particulate and mineral-associated organic matter pools from FSP soils and has expanded the original scope of this project by working with a relatively new ARS soil mineralogist to characterize the mineral-organic matter fraction. Samples of soybean grain from the FSP archives have been shared with collaborators who are conducting analyses to assess impact of cropping systems and presence and absence of weeds on nutritional content. The deep soil core samples collected from FSP in 2022 (1,988 samples) have been crushed and ground and are being analyzed for total C and N. Data on nitrogen inputs and outputs haves been compiled to assess nitrogen balances in the five FSP cropping systems Questions regarding soybean N-fixation and abundance of genes controlling nitrogen fixation were addressed in a recently published manuscript, showing that relationships among these factors are complex. The DRIVES network has submitted 2 papers, one describing the project (in review) and one describing the results from a network wide analysis of the impacts of crop rotations on crop yields (accepted). A NIFA grant has been received to continue the DRIVES network project, focusing on impacts of crop rotation on system resilience, economic performance, and the nutritional quality. FSP no-till corn yield and associated data have been used to test and validate the process based MAIZSIM model and a draft manuscript of this research has been written. Corn water use continues to be evaluated in six treatments of the LTAR LCB Croplands Common Experiment. At the end of 2024, five years of soil water data will have been collected and summarized. These data, along with five years of corn yield data, will be used to determine cover crop management influences on corn water use efficiency in spring of 2025. In support of Objective 2 research, the legume cover crop breeding program is making progress on cultivar release. There will be two commercially available lines released this year. Allelopathy selection continues in the early stages of the nursery development. The CC-NCALC decision tool has been updated to work with satellite imagery to give a geo-spatial assessment of cover crop performance in the field. A manuscript has been prepared on the integration of biophysical models with satellite imagery to extend the biomass predictions. Hyperspectral imagery has proven effective at measuring plant residue quality and a manuscript on this was submitted. The backend of the Vegetation Planning Tool has been constructed. The front end is almost complete. We have regionalized the cover crop species selector and seeding rate calculator for the southern and western cover crop councils.

Accomplishments
1. Combining data from long-term agricultural field experiments shows true effects of crop rotation diversity. Long-term agricultural field experiments (LTFEs) are a rich source of data for understanding how management and environmental factors impact cropping system performance. Combining data from multiple locations provides more robust analysis of general principles of agroecosystem structure and function than can be achieved with data from individual sites. A core team (8 people) of ARS and University scientists compiled a database (21 LTFEs in North America) to evaluate how crop rotational diversity impacts resilience in the face of adverse weather. This Diverse Rotations Improve Valuable Ecosystem Services (DRIVES) database was used to show that crop rotational complexity often improved crop returns compared with continuous monocultures. The greatest benefit was under poor growing conditions, showing that diversifying cropping systems can reduce risk, especially under conditions of increasing frequency and severity of stressful weather that is occurring with climate change. These results will be of interest to farmers, other scientists and policy makers.

2. Profitability of no-till farming increases with time. Farmers are often reluctant to adopt no-till management due to costs being greater than returns in the short term. ARS scientists from Beltsville, Maryland, along with university and other colleagues evaluated the long-term (1996-2019) economic impact of no-till adoption using crop yield and management data from a replicated long-term field study that included conventional and no-tillage corn-soybean-wheat/soybean rotations. Corn and soybean yields were similar in both systems, but wheat yields were greater in no-till than conventional till. Nonetheless, net returns (profits) per acre tended to be greater for no-till than conventional tillage, largely due to lower farm operation costs associated with no-till. In addition, the relative profitability of no-till increased with time. This insight supports suggestions from previous studies where long-term adoption of continuous no-till is important to best realize the benefits from the practice. These results will be of interest to farmers, scientists, carbon brokerage firms, and policy makers interested in climate smart agriculture.

3. Nitrogen fertilizer is a much more significant source than cover crops of nitrous oxide. While cover crops reduce nitrate leaching after cash crop harvest, their impact on emissions of nitrous oxide, an important greenhouse gas, are mixed. An ARS researcher from Beltsville, Maryland, along with University of Maryland researchers measured direct and estimated indirect emissions of nitrous oxide in two field experiments, both conducted on a sandy and a silty soil. Nitrous oxide emissions were almost eight times greater at the silty than the sandy sites due to greater soil moisture retention. Indirect nitrous oxide emissions were decreased about 7% by planting cover crops and by about 70% by planting cover crops early. On the silty soil, nitrous oxide emissions following fertilizer application were more than eight times greater than all previous nitrous oxide emissions, indicating that nitrogen fertilizers were a much more important source of nitrous oxide than cover crops. Results suggest that management to mitigate nitrous oxide emissions should consider soil texture and nitrogen fertilizer applications; cover crop management might be a secondary consideration. These results will be of interest to NRCS and other agencies working to reduce greenhouse gas emissions from agriculture.

4. Legume cover crops and forages improve sustainable nitrogen management. Predicting crop nitrogen requirements remains a challenging problem, especially in soils with a history of diverse organic inputs such as crop residues from diverse crop rotations, legume cover crops and forages, and manure amendments. Researchers in Beltsville, Maryland, conducted a three-year field study within the long-term Farming Systems Project to develop an improved understanding of how these factors influence soil nitrogen availability. The study revealed that available soil nitrogen the result of historic legume cover crop and poultry litter inputs reduced poultry litter plant available nitrogen requirements for corn by 46 to 58% (66 to 79 kg/ha, 59 to 71 lbs/acre) compared with current university recommendations in corn-soybean and corn-soybean-small grain rotations. However, long-term legume inputs from three-years of perennial alfalfa in a six-year rotation of corn-soybean-small grain-alfalfa-alfalfa-alfalfa eliminated any need for poultry litter application to corn. Farmers and nutrient management advisors will be able to use this information to make more efficient use of poultry litter, improving the environmental and economic performance of grain cropping systems reliant on this resource. Researchers will benefit from an increased understanding of the role of long-term agroecosystem management and inputs on soil fertility.

Review Publications
Welikhe, P., Williams, M.R., King, K.W., Bos, J.H., Akland, M., Baffaut, C., Beck, G., Bierer, A.M., Bosch, D.D., Brooks, E., Buda, A.R., Cavigelli, M.A., Faulkner, J., Feyereisen, G.W., Fortuna, A., Gamble, J.D., Hanrahan, B.R., Hussain, M., Kovar, J.L., Lee, B., Leytem, A.B., Liebig, M.A., Line, D., Macrae, M., Moorman, T.B., Moriasi, D.N., Mumbi, R., Nelson, N., Ortega-Pieck, A., Osmond, D., Penn, C.J., Pisani, O., Reba, M.L., Smith, D.R., Unrine, J., Webb, P., White, K.E., Wilson, H., Witthaus, L.M. 2023. Uncertainty in phosphorus fluxes and budgets across the U.S. long-term agroecosystem research network. Journal of Environmental Quality. 52(4):837-885. https://doi.org/10.1002/jeq2.20485.
Jennewein, J.S., Lamb, B.T., Hively, W., Thieme, A., Thapa, R., Goldsmith, A.S., Mirsky, S.B. 2022. Integration of satellite-based optical and synthetic aperture radar imagery to estimate winter cover crop performance in cereal grasses. Remote Sensing. https://doi.org/10.3390/rs14092077.
Reilly, K., Cavigelli, M.A., Szlavecz, M.A. 2023. Agricultural management practices impact soil properties more than soil microarthropods. Pedobiologia. https://doi.org/10.1016/j.ejsobi.2023.103516.
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.
Sedghi, N., Cavigelli, M.A., Weil, R.R. 2024. Cover crop effects on nitrous oxide emissions from no-till cropland in Maryland. Science of the Total Environment. Article e169991. https://doi.org/10.1016/j.scitotenv.2024.169991.
Silva, A.O., Lacerda, J. ., Carvalho, S., Ferreira, R., De Brito, R.E., Vogado, R.E., Neto, R.A., Sagrilo, E., Cavigelli, M.A., De Souza, H.S. 2024. Chemical and biological attributes of soil and soybean yield in integrated systems in the Cerrado of Northeast Brazil. Soil Research. 62. Article eSR23120. https://doi.org/10.1071/SR23120.
Kumar, V., Sing, V., Flessner, M., Reiter, M., Mirsky, S.B. 2023. Volunteer rapeseed infestation and management in corn. Agronomy Journal.115:2925–2937 https://doi.org/10.1002/agj2.21476.
Thapa, R., Cabrera, M., Schomberg, H.H., Reberg-Horton, C., Poffenbarger, H., Mirsky, S.B. 2023. Chemical differences in cover crop residue quality are maintained through litter decay. Ecological Applications. https://doi.org/10.1371/Journal.pone.0289352.
Liebert, J., Mirsky, S.B., Pelzer, C.J., Ryan, M.R. 2023. Optimizing organic no-till planted soybean with cover crop selection and termination timing. Agronomy Journal. 115:1938-1956. https://doi.org/10.1002/agj2.21390.
Chami, B., Niles, M.T., Parry, S., Mirsky, S.B., Ackroyd, V.J., Ryan, M.R. 2023. Incentive programs promote cover crop adoption. Agricultural and Environmental Letters. 8(2): Article e20114. https://doi.org/10.1002/ael2.20114.
Dobbs, A.M., Ginn, D., Skovsen, S., Yadav, R., Jha, P., Bagavathiannan, M.V., Mirsky, S.B., Reberg-Horton, S.S., Leon, R.G. 2023. Using Structure-from-Motion to estimate 302:109099. cover crop biomass and characterize canopy structure. Field Crops Research. https://doi.org/10.1016/j.fcr.2023.109099.
Meeks, C., Cabrera, M., Thapa, R., Reberg-Horton, S., Mirsky, S.B. 2023. Biochemical composition of cover crop residues determines water retention and rewetting characteristics. Agronomy Journal.6:3173-3187. https://doi.org/10.1002/agj2.21451.
Singh, M., Thapa, R., Singh, N., Mirsky, S.B., Acharya, B., Jhala, A.J. 2023. Does narrow row spacing suppress weeds and increase yields in corn and soybean? A meta-analysis. Weed Science. 71:520–535 https://doi.org/10.1017/wsc.2023.50.
Huddell, A.M., Thapa, R., Needelman, B., Mirsky, S.B., Davis, A.S., Peterson, C., Kladivko, E., Law, E., Darby, H., Mcvane, J.M., Haymake, J., Balkcom, K.S., Reiter, M., Vangessel, M., Ruark, M., Well, S., Gailans, S., Flessner, M.L., Mulvaney, M.J., Bagavathiannan, M., Samuelson, S., Ackroyd, V., Marcillo, G., Abendroth, L.J., Armstrong, S.D., Asmita, G., Basche, A., Beam, S., Bradley, K., Canisares, L.P., Devkota, P., Dick, W.A., Evans, J.A., Everman, W.A., Ferreira De Almeida, T., Fultz, L.M., Hashemi, M., Helmers, M.J., Jordan, N., Kaspar, T.C., Ketterings, Q.M., Kravchenko, A., Lazaro, L., Ramon, L.G., Liebert, J., Lindquist, J., Loria, K., Miller, J.O., Nkongolo, N.V., Norsworthy, J., Parajuli, B., Pelzer, C., Poffenbarger, H., Poudel, P., Ryan, M.R., Sawyer, J.E., Seehaver, S., Shergill, L., Upadhyaya, Y.R., Waggoner, A.L., Wallace, J.M., White, C., Wolters, B., Woodley, A., Ye, R., Youngerman, E. 2024. U.S. cereal rye winter cover crop growth database. Scientific Data. 11. Article. https://doi.org/10.1038/s41597-024-02996-9.
Rebong, D., Inoa, S.H., Moore, V.M., Reberg-Horton, C.S., Mirsky, S.B., Murphy, P.J., Leon, R.G. 2023. Breeding allelopathy in cereal rye for weed suppression. Weed Science. 72(1):30-40. https://doi.org/10.1017/wsc.2023.64.