Location: Agroecosystem Management Research
2022 Annual Report
Objectives
Objective 1: Determine the movement of nitrogen into and out of agroecosystems at critical points and develop practices to ameliorate losses.
Subobjective 1A: Develop a deep carbon injection practice utilizing byproduct cellulose to reduce nitrate leaching in sandy soils.
Subobjective 1B: Coordinate laboratory ammonia measurement to better estimate ammonia deposition impacts from nearby animal feeding operations.
Subobjective 1C: Determine the effects of emerging agricultural contaminants on nutrient transformation and decomposition.
Objective 2: Measure and mitigate pathogens, fecal indicators, and antibiotic resistance in agriculturally impacted environments and determine their interactions with healthy soils to lessen risk from the agricultural environments to natural environments.
Subobjective 2A: Develop and validate methods to detect and quantify AR genes, AR pathogens, and AR commensal organisms in agronomic and environmental matrices with a focus on resistance classes that are a human health priority, and that align with global AR surveillance efforts.
Subobjective 2B: Develop, optimize, and apply AgCROS Data Entry Templates (DET) for AR Data to assess relationships between soil physical, chemical, and biological measures and AR.
Subobjective 2C: Evaluate impact of fertilization and crop management strategy on AR in soils.
Objective 3: Improve mathematical representation of hydrologic processes influencing nutrient transport by overland flow on land application areas to reduce uncertainty associated with relevant nutrient applications and nutrient dynamics and to inform and strengthen opportunities for better management strategies.
Subobjective 3A: Quantify surface hydrologic processes influencing nutrient transport by surface runoff on cropland areas where beef and swine manure is applied.
Subobjective 3B: Use previously derived relationships and existing data to identify when and where to apply manure to maximize the use of nutrients and minimize nutrient losses to the environment.
Objective 4: Determine the ability of innovative fertilizer technology and precision fertilizer application to decrease nutrient loss to the environment and affect soil microbial function.
Subobjective 4A: Determine the effects of long-term variable fertilizer inputs and crop rotations on nutrient-transformations and antibiotic resistance within the soil microbial community as related to precision fertilizer application methods that may include Enhanced Efficiency Fertilizers (EEFs), bio-stimulants, manure, or biochar.
Subobjective 4B: Evaluate soil microbial community changes in cool-season grass pastures in response to nitrogen fertilizer management
Approach
The use of animal manures in farming impacts plant, animal, and human health, providing both benefits and challenges. Nutrient-rich animal manures are a boon to crop production; building soil organic matter, replacing expensive chemical fertilizers and enhancing soil physical and chemical properties. However, manured agronomic soils also present biosecurity risks to both ecosystems and human health, via runoff or leaching of excess nutrients, the impacts of excreted antibiotics and other emerging agricultural contaminants on carbon and nitrogen cycling in the soil, and the potential transfer of biological agents such as zoonotic pathogens and antibiotic resistant microorganisms. The proposed research project will address a number of critical knowledge gaps by i) identifying sources of excess nutrients (e.g., ammonia deposition near cattle feedlots) and the fate of nitrogen leaching into shallow groundwaters; ii) quantifying impacts of conservation practices in reducing nutrient transport and identifying manure management practices that optimize water quality and ecosystem health; iii) developing assays to detect microbes that cause and protect against disease across a continuum of rural-suburban-urban agronomic systems, and methods to support antibiotic resistance risk-assessment efforts; and iv) identifying the effects of manure associated pharmaceuticals on soil and aquatic ecosystem processes (nitrification and denitrification). Quantifying the benefit from sustainable nutrient (re)utilization and its associated positive effects of agronomic impacts to the soils on ecosystem, animal, and human health is a primary goal of this research. Coupled to this, and fully integrated into the larger research enterprise, are the collateral aspects of improving biosecurity and reducing adverse impacts potentially arising from this sustainable nutrient (re)utilization. Both aspects are important individual priorities of this research, but we are seeking to fully integrate these efforts for a more holistic, systematic understanding – one that provides clear systems level solutions to these problems arising from a common resource.
Progress Report
Progress was made on all objectives and milestones over the past year, and collaborative partnerships continued with other ARS research locations and researchers at universities working in similar areas. Progress was made in multiple projects investigating nitrogen movement and transformation in agroecosystems (Objectives 1 and 4). Three field studies with University of Nebraska collaborators were initiated. One study that entrenches waste wood chips below the root zone to limit nitrate leaching is underway in North Central Nebraska with numerous water leachate and greenhouse gas samples collected in treated and control corn fields. Two other collaborative studies in Eastern Nebraska involving numerous University of Nebraska collaborators and ARS scientists from Lincoln, Nebraska examine the impact of novel fertilizer use in grazing paddocks and in a corn-soybean rotation study. In the grazing paddock study, spring and fall soil samples have been collected, nucleic acids extracted, and are ready for analysis for nitrogen transformation genes and antibiotic resistance genes. The corn-soybean study examines nitrogen application amounts, timing, and forms (including enhanced efficiency fertilizers) in addition to cover crop effects to better manage nitrogen inputs and losses. Soils at the rotation site have been collected and evaluated for potential nitrogen transformation activities. Frozen samples await further analysis, and new soil health methods are being assessed using a multiple enzyme method in collaboration with an ARS scientist in Lubbock, Texas.
A final multi-location ARS field project focusing on ammonia deposition near animal production sites and its impact on local native ecosystems and crop production sites was also initiated at two sites (a cattle feedlot in South Central Nebraska and a swine production site in Central Iowa) which are currently installing meteorological instruments and passive samplers. Additional sites are slated for development based upon lessons learned at these two sites.
In Objective 2, the methods development work is ahead of schedule since a within- and cross-laboratory testing project was conducted ahead of schedule as part of an interagency working group. An antibiotic resistance data template has been developed, and plans are underway to meet with the Partnerships for Data Innovation team in 2023 to develop a more detailed work plan.
For Objective 3, analyses of existing experimental data show that nutrient transport on upland areas is influenced by the quantity of phosphorous (P) or nitrogen (N) released by soil, manure, or slurry at a given runoff rate and the amount of overland flow available to transport the P or N which is released. Nutrient transport rate increases in a linear fashion with runoff rate when manure is applied at agronomic rates. Once the maximum rate at which P release to overland flow is reached (point of inflection), P transport rates become constant. These results were delivered at an international meeting of the Soil and Water Conservation Society Conference in Denver, Colorado.
Accomplishments
Review Publications
Harzra, M., Durso, L.M. 2022. Performance efficiency of conventional treatment plants and constructed wetlands towards reduction of antibiotic resistance. Antibiotics. 11(1). https://doi.org/10.3390/antibiotics11010114.
Woodbury, B.L., Gilley, J.E., Parker, D.B., Marx, D.B. 2022. Emission of volatile organic compounds as affected by beef cattle diet and soil water content. Transactions of the ASABE. 65(1): 123-133. https://doi.org/10.13031/ja.14587.
Mware, N.A., Hall, M.C., Rejendran, S., Gilley, J.E., Bartelt-Hunt, S.L., Zhang, Y., Li, X. 2022. Resistome and mobilome in surface runoff from manured soil as affected by setback distance. Journal of Hazardous Materials. 429. Article 128278. https://doi.org/10.1016/j.jhazmat.2022.128278.
Singh, R., Ray, C., Miller, D.N., Durso, L.M., Meneses, Y., Bartelt-Hunt, S., D'Alessio, M. 2022. Effects of feeding mode on the performance, life span and greenhouse gas emissions of a vertical flow macrophyte assisted vermifilter. npj Clean Water. https://doi.org/10.1038/s41545-022-00171-4.
Min, B.R., Lee, S., Miller, D.N., Chen, R. 2022. A review: Enteric methane emissions and animal performance in dairy and beef cattle production: enumerating the opportunities and impact of reducing emissions. Animal. 12(8):948. https://doi.org/10.3390/ani12080948.
Cooper, J.A., Drijber, R., Malakar, A., Jin, V.L., Miller, D.N., Kaiser, M. 2022. Biochar and coal char mitigate nutrient and dissolved organic carbon loss from liquid manure amended soils. Environmental Quality. 51(2):272-287. https://doi.org/10.1002/jeq2.20327.
Messer, T.L., Miller, D.N., Little, H., Oathout, K. 2021. Nitrate-N removal rate variabilities in floating treatment wetland mesocosms with diverse planting and carbon amendment designs. Ecological Engineering. https://doi.org/10.1016/j.ecoleng.2021.106444.
Brooks, J.P., Durso, L.M., Ibekwe, A.M. 2021. Editorial: Exposure, risks, and drivers of the mobile antimicrobial resistance genes in the environment – a global perspective. Frontiers in Microbiology. 12:1-3. https://doi.org/10.3389/fmicb.2021.803282.
