Location: Livestock Bio-Systems
2019 Annual Report
Objectives
Objective 1: Determine the impact of meat animal dietary changes on manure and the environment.
Sub-objective 1A: Determine if a moderate and aggressive implant strategy with and without ß-agonists reduces odorous volatile organic compounds (VOCs) and GHG production from fresh and stored beef manure (Spiehs).
• Sub-objective 1B: Determine if the addition of ferric citrate to beef feedlot diets reduces nutrient excretion, GHG, and odorous VOCs from fresh and stored beef manure (Spiehs).
• Sub-objective 1C: Determine if the addition of an ionophore to improve feed efficiency reduces odorous VOCs and GHG production from fresh and stored beef manure (Spiehs).
Objective 2: Develop practices for reducing environmental impacts of nutrients, pharmaceutical residues, gaseous emissions and other agricultural waste on soil and air quality through improved manure management and control systems.
• Sub-objective 2A: Conduct a series of laboratory studies to determine the impact of within pen spatial location and climatic conditions on GHG and odorous VOCs emissions from beef feedlot pen surfaces and the effectiveness of surface amendments as a mitigant (Woodbury and Spiehs).
• Sub-objective 2B: Evaluate the use of electromagnetic induction (EMI) and response surface sampling design (RSSD) as tools for predicting emission spatial variability on commercial-sized pen surfaces (Woodbury).
• Sub-objective 2C: Evaluate the addition of surface amendment on commercial-sized pens for reducing odorous VOCs and GHG emissions (Woodbury and Spiehs).
• Sub-objective 2D: Determine occurrence of antimicrobial resistance following land application of cattle manure to agricultural soils (Spiehs and Woodbury).
• Sub-objective 2E: Determine residual steroid and ß-agonist concentrations in feces and urine of beef cattle administered a moderate and aggressive implant strategy with and without ß-agonists (Spiehs).
Objective 3: Develop measurement technologies for manure contaminants that can be used for conducting field-scale fate and transport studies in crop and pasture systems.
Sub-objective 3A: Develop techniques and analysis software protocols that will enable the wide-spread use of resistivity array (RA) technology by pond managers as an early-warning system for detecting unintended sub-surface discharge (Woodbury and Eigenberg).
• Sub-objective 3B: Develop techniques for tracking and mapping the 2-dimentional transport of antimicrobial residues in crop and hay fields (Woodbury and Eigenberg).
• Sub-objective 3C: Determine the effectiveness of flocculation for removing excreted veterinarian pharmaceuticals from beef runoff wastewater and swine-manure lagoon water (Woodbury and Spiehs).
Approach
Concentrated animal feeding operations are a source of environmental concerns, and are creating unease between livestock producers and the rural and urban communities, dependent upon livestock production. The organic, inorganic, pathogenic, and pharmaceutical residues in manure are potential sources for contamination of soil, surface and groundwater, and air quality. The multifaceted, integrated research proposed here will provide valuable information for managing the impact of manure on the environment. This work is centered on beef production and the pen surface since it is where manure is most concentrated and management can have the greatest impact. The approach begins at the pen surface by examining inputs such as diets. Experiments will investigate how inputs such as feed additives and pharmaceutical supplements alter the nutrient composition of beef manure and resulting air quality. Next, a series of experiments are planned to better understand how emission characteristics vary based on the spatial location within the pen. In addition to the spatial component, a series of studies will continue developing a database of the impact climatic conditions have on the types and amounts of emissions from pen surfaces. It is anticipated this information will provide insight for the development of precision pen surface management practices for improved environmental control. Additional experiments will examine the transport and fate of antimicrobials and nutrients through commercial-sized beef production systems. Successful completion of this work will benefit livestock producers by helping them apply best management practices and equipping them to be good stewards for sustainable agriculture.
Progress Report
A laboratory study was conducted to determine the effect of surface amendments applied to feedlot pens on emissions of greenhouse gas and other odorous compounds (Objective 2). Aluminum sulfate (alum) was added at a rate of 10% of the mass of pen surface material at two frequencies (once, weekly allotments). Over a 35-day collection period, emissions of ammonia, nitrous oxide, and carbon dioxide were reduced when alum was added, with no differences detected in gas emissions between the two application rates. Hydrogen sulfide emissions were higher when alum was added.
A final year of data was collected from a laboratory study on manure collected from spring- and fall-born calves to determine the impact of anabolic steroids on odor production (Objective 1). Use of an aggressive implant that contained higher concentrations of trenbolone acetate resulted in lower carbon dioxide, methane, and nitrous oxide flux compared to cattle given a moderate implant. Ammonia and hydrogen sulfide emissions were higher from the manure of cattle given the aggressive implant compared to cattle given the moderate implant.
Soil samples collected from fields that received land application beef cattle manure, beef manure mixed with bedding, commercial fertilizer, and no fertilizer were analyzed for antimicrobial resistant bacteria and antimicrobial resistance genes (Objective 2D). Results indicated that manure amendment did not impact cropland antimicrobial resistant bacteria levels and had no or minimal impact on antimicrobial resistance gene levels. Most differences observed in antimicrobial resistances levels were due to sample occasion. Paper was submitted for publication and is currently under review.
A cost-effective treatment method for removing antibiotics from agricultural wastewater was investigated (Objective 2). Livestock and other industry stakeholders have concerns about antibiotic contamination in wastewater and the possibility of negative environmental effects. ARS researchers in Clay Center, Nebraska, determined that diatomaceous earth (DE) effectively binds and removes antibiotics from agricultural wastewaters even under extreme conditions such as high salt concentrations and varying pH. The efficiency that DE binds and removes antibiotics makes it an ideal component for a cost-effective treatment option. Additional work was completed to synthesize other binding agents to be used in combination with DE to expand the number of antibiotics, antibiotic metabolites and other endocrine-disrupting contaminants removed from wastewater. Preliminary analysis demonstrated these binding agents have promise for expanding the types and amounts of contaminants removed by this process. This wastewater treatment process was developed for agricultural use but can also be used effectively for municipalities.
Greenhouse gas emissions from feedlot surfaces is largely a microbially mediated process affected by the types of organic material used as a food source, temperature, moisture and the types of organic material. An investigation was conducted to better understand this process to develop practices for control (Objective 2A, Experiment 2A.2). Emissions under wet conditions for carbon dioxide, methane, and nitrous oxide were 35, 121, and 278 times greater, respectively, than emissions from dry surfaces. Additionally, diets without distillers grains produced carbon dioxide and nitrous oxide emissions that were 1.8 and 1.5 times greater, respectively, than diets containing 35% distillers grains. The distillers grain diet, in contrast, produced methane emissions that were 6 times greater than diets without distillers grains. Based on these results feedlot managers need to consider several factors to more effectively reduce greenhouse gas (GHG) emissions, including maintenance of pen drainage to speed drying as well as the composition of feedlot rations for beef cattle.
A process was developed for removing antimicrobials from agricultural wastewater (Objective 2A). Several types of diatomaceous earth were examined that contained the most clays and organic matter was the most efficient for removing certain antibiotics. The effectiveness of this diatomaceous earth was improved by removing the organic matter coating the particles. Once bound, the diatomaceous earth with the antimicrobials were separated from wastewater before being used for irrigation. Regeneration of diatomaceous earth is being tested to determine the recyclability of the material for wastewater treatment.
A laboratory study was conducted to evaluate the effects of pen location based on electromagnetic induction (EMI) analysis on volatile organic compounds (VOC) from feedlot pens where beef cattle were fed a diet containing 30% wet distillers grain plus solubles (Objective 2B). Surface materials were collected from the feed trough (bunk), drainage, and raised areas (mounds) within three feedlot pens. The largest volatile fatty acids (VFA) and aromatic emissions resulted for the dry moisture condition typical near the base of the mound while wet and saturated conditions produced the largest sulfide emissions. Odor activity value (OAV), which was the ratio of measured concentration of a single compound normalized to the odor threshold for that compound, was calculated for each compound. Four volatile fatty acid compounds contributed 7.5% of the total OAV but only one aromatic, 4-methylphenol, was a major contributor to total OAV at 2.5%. In comparison, sulfide compounds from behind the feed bunk area contributed 87.3% of the total OAV. This research shows VOC emissions are affected by conditions that are driven by specific locations within the pen. Additionally, EMI analysis has potential to identify these within pen locations generally driven by pen design. Therefore, EMI can be used to identify the relatively small surface area of the pen emitting. Once identified, a cost-effectively mitigation practice can be implemented focused on the small areas emitting and not applied to the entire pen.
Understanding the fate and transport process of antibiotics at the field-scale is complicated and difficult to understand due to the number of factors at that scale effecting the process (Objective 3). Electromagnetic induction (EMI) analysis was used to identify areas of a vegetative treatment system receiving disproportional amounts of feedlot runoff. Antibiotics used during the production of livestock are contained in this runoff and therefore, these soils are being loaded with greater amounts of the antibiotics. It is theorized these areas may be key for controlling the fate and transport of these antibiotics in the environment. Preliminary analysis of the data indicates EMI is an effective tool for identifying these critical control points in a vegetative treatment area receiving feedlot runoff. Work continues developing this EMI analysis technique for determining critical control points. Once these control points are identified, then an effective practice can be developed to mitigate the environmental impact of antibiotics on the environment.
Crop fields receiving feedlot runoff can have critical control points where management practices can be implemented to mitigate antibiotic impact on the environment (Objective 3). A similar study to the vegetative treatment study described above was conducted on a crop field receiving feedlot runoff. This field has a history of greater than 40 years of receiving feedlot runoff; however, routine use of antibiotics at this facility only have been implemented over the last 20 years. The field was recently rotated out of alfalfa to soybeans. Establishing the statistical parameter of normal distribution of the apparent electrical conductivity as measured by the EMI analysis was not achieved. Therefore, the ability to use response surface sampling design to establish calibration sites could not be used. It was theorized this field has small areas of very high apparent electrical conductivities and large areas of relatively low conductivities that complicated the normal distribution. Additional work will be done modifying the technique to determine if a way can be developed to use EMI effectively.
Accomplishments
1. Land application of beef manure impacts greenhouse gas emissions. Land application of beef cattle manure can improve soil health and increase corn yield compared to commercial fertilizer. However, ammonia, nitrous oxide, carbon dioxide, and methane emissions from land application of manure may lead to nutrient losses and environmental concerns. ARS scientist at Clay Center, Nebraska, conducted a study to determine emissions when solid beef manure, solid beef manure mixed with bedding, commercial fertilizer, and no fertilizer were land applied to corn fields. Emissions were measured over two years. Manure application reduced cumulative nitrous oxide loss 23-31% compared to commercial fertilizer and increased residual soil nitrogen, but cumulative carbon dioxide emission was 42% lower when commercial fertilizer was used compared to manure with or without bedding. Corn yield was not different between fields that received commercial fertilizer and manures. Use of manures as crop fertilizers allows producers to recycle nutrients in their production system, use less commercial fertilizer, and reap the beneficial aspects of manure application to soil health without negatively affecting nitrogen emissions from corn fields.
2. Using biochars as an air filter media for controlling odors from swine facilities. ARS scientists at Florence, South Carolina, and Clay Center, Nebraska, pyrolyzed nine biochars from livestock manure and plant-based sources. These sources were evaluated for their ability to bind 15 odorous compounds as an air filter at the laboratory scale. Acetic acid was the primary odorous compound emitted from swine manure. However, two sulfur containing compounds contributed the most to odor offensiveness. Oak biochar pyrolyzed at 500 degrees Celsius, oak biochar pyrolyzed at 350 degrees, and coconut shell biochar pyrolyzed at 500 degrees were the most effective of the biochars tested at removing sulfur compounds. Oak biochar pyrolyzed at 500 degrees had a sorption capacity for dimethyldisulfide 138% and 349% greater than coconut shell biochar and oak biochar pyrolozed at lower temperature, respectively. Sorption capacity for the oak biochar for dimethyltrisulfide was 99.8% and 108% that of the coconut shell biochar and oak biochar pyrolyzed at 350 degrees, respectively. Oak biochar pyrolyzed at 500 degrees Celsius has about 35% of the sorption capacity for sulfur compounds as activated carbon. Results from this study were used to develop a pilot-scale study evaluating efficacy upon scale-up of the approach. Additional work will evaluate using the spent biochar as soil amendment to improve soil health and sequester carbon. These studies are ongoing. This approach has the potential to mitigate odors emitted from swine facilities benefitting producers and the general public.
3. Environmental fate and microbial effects of select antibiotic residues on soils. ARS researches at Clay Center, Nebraska, evaluated select antibiotics to determine their impact on the soil microbial community at the laboratory scale. Soils receiving antibiotics affected normal microbial respirations and nitrogen transformations. Discontinuing soil exposure to these antibiotics allowed normal microbial function to return such as denitrification. Periodically exposing soils to livestock antibiotics temporally changed soil microbial activities. A subtle long-term change in the microbial composition in the upper layer of the soil was observed; however, the changes for the lower soil levels were more transitory. Altering soil microbial communities can have long-term impact on soil nutrient cycles, particularly for nitrogen and possibly carbon. These changes may impact soil health and productivity when manure and wastewater containing antibiotics are repeatedly added to soil as a fertilizer amendment or irrigation water. Application of manure as a fertilizer amendment may have to consider the impact on the soil microbial communities when determining application rate and frequency. In addition, a cost-effective treatment process for wastewater used as irrigation will have to be developed to mitigate long-microbial shift. Better management of the impact on soil microbial communities will sustain soil productivities.
4. Wheat strip influences microbial transport of manure amended soils. Vegetative filter strips using perennial grasses have been shown to be effective for controlling microbial transport of manure amended soils to surface water. However, this takes valuable land out of production. An approach using annual planting of winter wheat strips as a filter could be an effective control and be harvested as a cash crop. ARS researchers at Clay Center, Nebraska, investigated the use of 1.4-meter wide winter wheat strips for controlling microbial transport. The narrow wheat strip did not significantly reduce microbial counts. Result of this research suggests narrow winter wheat strips were not an effective control measure and is not a viable substitute to perennial grass strips.
5. Microbial transport of manure amended soils as affected by crop residue levels. Manure is applied to agricultural soils to meet multiple year crop nutrient requirements. These agricultural soils can have varying levels of crop residue. ARS researchers at Clay Center, Nebraska, conducted a study to determine microbial transport as affected wheat residue, compare microbial loads following varying application rates of manure to meet multiple year crop requirements of phosphorus and evaluate the effect of a series of rainfall on the microbial transport. Runoff from plots containing wheat straw residue had significantly greater coliform loads than the plots without wheat residue. As the manure application rate increased, the microbial counts in the runoff also increased significantly. Successive rainfall simulations did not significantly affect certain microbial counts in the runoff, but others were significantly affected. These results indicate that crop residue and amendment rates should be a consideration when applying manure to soil that potentially can contaminate surface water. Improved management of manure amended soil allows producers to reduce their environmental impact and improve environmental water quality.
6. Continued evaluation of two Wastewater Pond Leak Detectors in the state of Washington. Wastewater Pond Leak Detectors developed by ARS researchers at Clay Center, Nebraska, were installed in the state of Washington to further test the capacity of the system. Data from the installation indicated a potential nutrient leach from a composting site near the wastewater ponds. The composting site was modified to reduce leaching. This project confirms the sensitivity of the new technology for leak detection and for isolating activities adjacent to wastewater ponds that may be impacting the environment. Regional verification of the Leak Detection system empowers managers to be proactive in protecting groundwater for wastewater or animal manure contaminants.
Review Publications
Hwang, O., Lee, S.R., Cho, S.B., Ro, K.S., Spiehs, M.J., Woodbury, B.L., Silva, P.J., Han, D.W., Choi, H.C., Kim, K.Y., Jung, M. 2018. Efficacy of different biochars in removing odorous volatile organic compounds (VOCs) emitted from swine manure. ACS Sustainable Chemistry & Engineering. https://doi.org/10.1021/acssuschemeng.8b02881.
Niraula, S., Rahman, S., Chatterjee, A., Cortus, E.L., Mehata, M., Spiehs, M.J. 2019. Beef manure and urea applied to corn show variable effects on nitrous oxide, methane, carbon dioxide, and ammonia. Agronomy Journal. 111(3):1448-1467. https://doi.org/10.2134/agronj2018.08.0547.
Durso, L.M., Gilley, J.E., Marx, D.B., Woodbury, B.L. 2019. Narrow grass hedge effects on microbial transport following variable applications of beef cattle manure. Transactions of the ASABE. 62(1):149-156. https://doi.org/10.13031/trans.12892.
Durso, L.M., Gilley, J.E., Marx, D., Thayer, C., Woodbury, B.L. 2019. Wheat strip effects on microbial transport following variable applications of beef cattle manure. Transactions of the ASABE. 62(2):263-270. https://doi.org/10.13031/trans.12940.
