Location: Livestock Bio-Systems
2024 Annual Report
Objectives
Objective 1: Develop pen surface amendments and treatment practices for concentrated animal feeding operations (CAFO) to reduce emissions to the environment, including greenhouse gases (GHG) and odors.
Sub-objective 1.A: Determine the effect of climatic conditions on GHG and odor emission from beef feedlot pen surfaces from various geographical locations.
Sub-objective 1.B: Evaluate the addition of feedlot surface amendment(s) in lab-scale studies to reduce emission of GHG and odorous compounds from beef feedlot pen surfaces from various geographical locations.
Sub-objective 1.C: Evaluate the validity of using electromagnetic induction surveys to predict and mitigate spatially variable feedlot surface GHG and odor emissions.
Sub-objective 1.D: Determine seasonal and annual ammonia transport and dry deposition from beef confinement facilities in and around the livestock facility.
Sub-objective 1.E: Determine NH3 and H2S emissions from swine finishing barns and manure storage based on feed inputs.
Sub-objective 1.F: Continue developing treatment methods for removing certain antimicrobials from wastewater and expand the efficacy of this process for additional pharmaceutically active compounds.
Objective 2: Quantify how long-term manure additions to soil alter soil health as measured by chemical, physical, and biological properties.
Approach
Concentrated animal feeding operations (CAFOs) cause environmental concerns because of the organic, inorganic, pathogenic, and pharmaceutical residues sometimes found in manure and their potential as sources for contamination of soil, surface and groundwater, and air quality. The multifaceted, integrated research proposed herein will provide valuable information for managing the impact of manure on the environment. This work focuses on beef and swine production with an emphasis at the pen because that is where manure is most concentrated, and where management can have a significant impact. A series of experiments are planned to better understand how emission characteristics vary based on climatic conditions and geographical location within the U.S. of open-lot beef pen surface material (PSM). Effects of spatial location within the pen will also be examined. It is anticipated this information will provide insight for the development of precision pen surface management practices for improved environmental control, including the use of pen surface amendments. Nitrogen deposition surrounding the beef feedlot, and the effect of dietary inputs on nitrogen (N) and sulfur (S) outputs from a swine facility will contribute towards larger efforts to model air emissions from livestock production facilities. Additional experiments will develop methods to remove antibiotics and other pharmaceutical compounds in beef, swine, and dairy wastewater prior to land application. The removal of antibiotics and other pharmaceutical compounds will mitigate the potential spread of antimicrobial resistance (AMR) in the environment. Finally, the impacts of manure application as a fertilizer amendment will be examined to better characterize the benefits for improving sustainability of soils for crop production. The unique resources and scientific expertise at the U.S. Meat Animal Research Center (USMARC) will enable successful completion of this plan.
Progress Report
Sub-objective 1A: Data has been analyzed from the research project to determine the effect of climatic conditions on greenhouse gas (GHG), and odor emission from beef feedlot pen surfaces from Texas and Nebraska. Studies were conducted using pen surface material (PSM) from Texas and Nebraska at three moisture levels defined as dry (air-dried), wet (1:2 water-to-PSM ratio), and saturated (1:1 water-to-PSM ratio) and three different ambient temperatures (15, 25, and 35°C). Ammonia (NH3) and carbon dioxide (CO2) emissions were higher from PSM from Nebraska, while PSM from Texas emitted more nitrous oxide (N2O) than PSM from Nebraska. Ammonia emissions increased at higher ambient temperatures, while the other gases were largely unaffected by temperature. The research will be presented at the Annual International Meeting of the American Society of Agricultural and Biological Engineers in July 2024.
Sub-objective 1B: Lab-scale and on-farm studies have been conducted to evaluate the addition of feedlot surface amendments and animal diet on feedlot surface characteristics, odor, and gas emissions. Lab-scale experiments have been conducted to evaluate the effectiveness of microbial and chemical feedlot surface amendments. Air samples were analyzed for volatile organic compounds (VOC), NH3, hydrogen sulfide (H2S), and greenhouse gases including N2O, methane (CH4), and CO2. One lab-scale study evaluated the use of aluminum chloride as a pen surface amendment at concentrations of 0, 2.5, 5, and 10%. A second study examined emissions from PSM with and without long-term feeding of ethanol by-products.
An on-farm project is on-going in June – July 2024, at a Clay Center, Nebraska, beef feedlot to evaluate the addition of a microbial additive added to the feedlot surface area. This study provides a second year of data for a project initiated in 2023. Air samples are being collected on five occasions over an 18-day period and analyzed for odorous VOC, NH3, H2S, CO2, N2O, and CH4. Manure nutrient content and pH is also being determined at the beginning and the end of the study.
Additional studies evaluating will begin in August 2024 to compare the use of aluminum chloride and a microbial additive as pen surface amendments in 42-day wet-dry cycles to determine how the two amendments reduce odorous VOC, NH3, H2S, CO2, N2O, and CH4 over time. A final study is also planned to start in September 2024 to evaluate blended beef and chicken manure with considerations of soil properties and emission of GHG and VOCs.
Sub-objective 1D: To determine seasonal and annual NH3 transport and dry deposition from beef confinement facilities in and around the livestock facility, a meteorological station was erected, and twenty-five data collection points established in an array surrounding a 6,000-animal beef feedlot located near Clay Center, Nebraska. Data has been collected every other week since August 2023 and sent to the ARS facility in Lincoln, Nebraska, for NH3 analysis. Weather and ammonia data is sent to the U.S. Environmental Protection Agency for integration into their NH3 deposition model. Data collection using Ogawa passive NH3 samplers will continue through 2025. Plant tissue samples were also collected quarterly to determine nitrogen deposition onto plant tissue.
Sub-objective 1E: The project to determine NH3 and H2S emissions from a swine finishing barn and manure storage based on feed inputs was initiated in 2024. Data collection is complete for the Iowa barn.
Sub-objective 1F: A series of experiments were conducted to confirm that diatomaceous earth could remove antibiotics from spiked beef wastewater when used in tandem with other wastewater treatment technology, flocculation. The addition of a flocking agent aluminum sulfate did not significantly alter the performance of diatomaceous earth as a remediation material for tylosin and improved the efficiency of diatomaceous earth for removal of ceftiofur. The removal of ceftiofur, despite increase in efficiency, remained low for diatomaceous earth. Studies were also conducted to synthesize a new material to be applied as a remediation method for wastewater. Langmuir binding isotherms were constructed to determine that ceftiofur was more efficiently removed by the new material compared to previously used diatomaceous earth. Other compounds were used as surrogate molecules to demonstrate the new materials ability to remove certain compounds from a solution at a higher efficiency than diatomaceous earth. Contact angle studies, along with bromophenol blue binding studies, provide evidence that the newly synthesized material is hydrophobic in nature.
Objective 2: To quantify how long-term manure additions to soil alter soil health, yearly samples will be collected and analyzed from a 12 year-long fertilizer study comparing commercial fertilizer with manure to meet the nitrogen needs for a corn silage crop that was terminated approximately 15 years ago. Both treatments had a cover crop and a no-cover crop treatment. Samples were collected following corn harvest in October 2023. It was determined by the Dairy Agrowaste Group (DAWG) that additional years of data would be beneficial, so soil samples will be collected again following the 2024 corn harvest.
Accomplishments
1. Pen surface amendments reduce odor and greenhouse gas emissions. Livestock producers face increasing pressure to reduce ammonia and greenhouse emissions from their operations. One way livestock producers can reduce these emissions is to apply products to the pen surface that prevent the release of these gases into the air. ARS researchers at Clay Center, Nebraska, identified two amendments that successfully lowered emissions from beef pen surfaces. Aluminum sulfate, known commonly as alum, is an amendment that lowers the pH of the pen surface material and traps the nitrogen to keep it from volatilizing into the air. A variety of pit additives are commercially available for use in liquid swine and beef manure pits. These microbial additives contain a mixture of enzymes and bacteria to break down manure solids and promote the growth of beneficial bacteria in underground liquid manure storage pits, but hadn’t been tested on beef pen surface material. When tested in a lab-scale setting, ammonia, nitrous oxide, and methane were lower from pen surface material treated with both these amendments compared to the untreated pen surface material. The microbial product was most beneficial at reducing methane emission. This research identified practical tools that will lead to new approaches that allow livestock producers to reduce greenhouse gas emissions for more sustainable beef production.
2. Identifying the best bedding materials for confinement beef facilities. Producers have bedded livestock and poultry for centuries with locally available crop- and wood-based bedding materials. However, the choice of bedding material can affect animal health and behavior, pen and animal cleanliness, and air quality in the facility. Bedding materials are often selected based only on availability of supply and cost, without consideration for these other factors. This may be due to a lack of understanding regarding how these factors influence profitability and a general lack of information about the physical properties of a particular bedding material. ARS scientists at Clay Center, Nebraska, conducted a study to determine the amount of water that bedding materials could absorb (water holding capacity) and how quickly the bedding materials would release the water into the atmosphere (rate of evaporative water loss). Corn stover, soybean stover, wheat straw, switch grass, paper, corn cobs, pine, dry cedar, and green cedar were evaluated at three different particle sizes. All bedding materials absorbed more water when more finely ground to smaller particle sizes. Corn stover and wheat straw were able to absorb the most water, with corn cobs retaining water the longest. Pine chips and soybean stover had the best combination of water absorption and holding capacity. This information fills critical gaps in knowledge and helps producers decide the best bedding materials to use in their operations. This work should promote improved animal health and environmental sustainability of beef production systems.
Review Publications
Spiehs, M.J., Woodbury, B.L. 2023. Ammonia and greenhouse gas emissions from beef feedlot surface material treated with aluminum sulfate (alum) or microbial amendments. Journal of Environmental Quality. 53(1):1-11. https://doi.org/10.1002/jeq2.20533.
Spiehs, M.J., Woodbury, B.L., Brown-Brandl, T.M. 2023. Chemical and physical properties of organic bedding materials. Applied Engineering in Agriculture. 39(6):595-604. https://doi.org/10.13031/aea.15673.
Leytem, A.B., Dungan, R.S., Spiehs, M.J., Miller, D.N. 2024. Safe and sustainable use of bio-based fertilizers in agricultural production systems. In: Amon, B., editor. Developing Circular Agriculture Production Systems. 1st edition. Cambridge, UK: Burleigh Dodds Science Publishing. p. 179-214. https://doi.org/10.19103/AS.2023.0120.16.