Location: Livestock Nutrient Management Research2018 Annual Report
Objective 1: Characterize and improve prediction of ammonia and greenhouse gas emissions from cattle production systems. Subobjective 1A. Characterize methane (CH4) emissions from southern Great Plains grazing systems. Subobjective 1B. Assess the impact of environmental conditions and management practices and their interactions on emissions of NH3 and GHG from open lot cattle production systems. Subobjective 1C. Improve NH3 and GHG emissions measurements for feedyards and dairies. Objective 2: Improve feed nutrient use in cattle to maintain animal productivity, reduce emissions of ammonia and greenhouse gases, and mitigate pathogens and antibiotic resistant bacteria. Subobjective 2A. Determine effects of cattle diet on enteric CH4 production. Subobjective 2B: Evaluate and improve models to predict enteric CH4 emissions from grazing and feedyard cattle. Subobjective 2C. Identify and quantify sources of enteric nitrous oxide (N20) emissions from cattle in respiration calorimetry chambers. Objective 3: Manage soil and manure reactive nitrogen, phosphorus and carbon to improve soil properties, reduce nutrient loss and mitigate pathogens and antibiotic resistant bacteria. Subobjective 3A. Evaluate the effectiveness, practicality and economics of chemical inhibitors and manure amendments to reduce N20 and NH3 emissions from beef cattle feedyards, dairies, and manure-amended soils. Subobjective 3B. Quantify field-scale emissions of N20 from manure-amended soils. Subobjective 3C. Establish protocols for examining AR in agroecosystems. Subobjective 3D. Characterize forms of P in manure-amended soils. Subobjective 3E: Evaluate soil C/N change with land use on the southern High Plains.
Beef and dairy cattle production provide vital human nutrition and important economic activity. Cattle production, like all human endeavors, also contains environmental risks. This multidisciplinary research will help us to better understand and mitigate the environmental risks from cattle production systems on the Southern Great Plains. We will quantify and improve predictions of emissions of ammonia (NH3) and greenhouse gases (GHG) from cattle production systems. The research will focus on the predominant agricultural GHG emissions of methane (CH4) and nitrous oxide (N20). Sources of these emissions include grazing animals (enteric emissions), emissions from cattle, pen and lagoon surfaces at beef feedyards and dairies, and emissions from soils following land application of manure. We will determine the effects of cattle diet on enteric GHG emissions on scales that range from single animal to whole pastures, feedyards or dairies. We will test potential mitigation methods to reduce emissions from manure surfaces and cropped fields using controlled laboratory experiments followed by pilot-scale and field-scale experiments. We will quantify the changes in soil carbon (C), nitrogen (N), and phosphorus (P) from application of manure or land use change. A collaboration of ARS laboratories will test methods to characterize antibiotic resistant (AR) bacteria and genes from manure-impacted soil. Research results will provide science-based information and technologies for livestock producers, extension specialists, and regulators to protect air quality, manage feedyard and dairy manure, enhance production efficiency, and improve sustainability of livestock production.
Research of the Livestock Nutrient Management Research Unit in FY18 was conducted during the second year of the project plan "Improved Practices to Conserve Air Quality, Maintain Animal Productivity, and Enhance Use of Manure and Soil Nutrients of Cattle Production Systems for the Southern Great Plains". There were fifteen Year 2 milestones; ten were fully met, three were substantially met, and two were not met. The unit's vacant Research Animal Scientist position was filled and our new scientist is on staff as of June, 2018. We completed Year 5 of the five-year NIFA Grazing CAP, a multi-institutional effort to understand the effects of grazing cattle on greenhouse gases and the resilience of grazing systems to climate change. We are wrapping up work on the CAP project under a one-year no fund extension. Scientists at Bushland were key contributors to the field research and mitigation practices objectives of the CAP grant and served on the project leadership team. Unit scientists actively participated in the ARS-led Dairy Agroecosystem Working Group (DAWG) and participated in two DAWG conferences and published one manuscript. Scientists were involved in the ARS Grand Challenge project "Dairy Agriculture for People and the Planet (DAPP)". We characterized emissions from cattle production systems using novel approaches to measure emissions of greenhouse gases. A database collected from three intensive field campaigns in collaboration with the Grazing Research Laboratory, El Reno, Oklahoma was analyzed and methane emissions quantified. Results were presented at two national meetings, a cattle producers’ conference, and the capstone meeting of the Grazing CAP. We continued to monitor methane and carbon dioxide emissions from a High Plains pasture soil to test whether semiarid upland soils are sources or sinks of the greenhouse gases carbon dioxide and methane. A flux chamber system was re-designed for quantifying nitrous oxide emissions from manure. The 20 chambers, each with 0.25 square meter footprint, were mounted on a rail system to facilitate indoor and outdoor research. Using a real-time analyzer, the system was optimized to quantify nitrous oxide concentrations in a short 60 second measurement period, as compared to traditional methods which take 30 to 60 minutes. The system was used to assess the effect of temperature, precipitation and urine on nitrous oxide emissions. Using nitrous oxide data collected from one chamber study, manures were analyzed for physicochemical properties, nutrient contents, enzyme activities, and microbial community composition. The goal was a biochemical-level understanding of manure-derived nitrous oxide and methane losses so that targeted mitigation approaches could be developed. Denitrification and nitrification enzyme activity assays for soils were modified and conducted on manure taken from different depth of the chamber study. A student assistant was trained to develop and optimize these enzyme assays. From these data we ascertained that nitrous oxide occurs via nitrification or denitrification, but the mechanism and magnitude of nitrous oxide flux depends upon temperature, water content, and other manure properties. Results from controlled laboratory incubations confirmed the variable and dynamic nature of nitrogen transformation and emissions from manure, and how they differ from typical emissions from soil. In another study, Bushland researchers adapted a meta-analytical approach to develop empirical equations for feedyard nitrous oxide based on emissions measured from static chambers during eight 4-day measurement campaigns. Manure samples were analyzed for basic nutrient content and carbon quality. This work revealed the importance of soluble carbon as an energy substrate for microbes involved in nitrous oxide production. Evaluation of the new models showed improved predictive ability, particularly during large flushes of nitrous oxide after rainfall. Experiments to improve feed nutrient use of cattle to maintain animal productivity and reduce emissions of ammonia and greenhouse gases focused on testing the effects of different diets on emissions of individual animals. Nitrous oxide emissions produced enterically in cattle were measured in respiration calorimetry chambers and found to be considerably lower than original estimates. Nitrous oxide emissions were directly related to the amount of nitrate in the feed. The global warming potential from belched nitrous oxide was much smaller than from belched methane. A 4-week respiration calorimetry trial was conducted using 8 steers fed blue stem hay diets to assess the effect of forage quality on methane production in cattle. Diet ingredients were collected monthly throughout the trial. Gas samples were also collected daily in the chambers and analyzed. Fecal samples, orts samples, and urine samples were composited by animal and period and given to the laboratory for analysis. The samples were analyzed for dry matter, organic matter, neutral detergent fiber, acid detergent fiber, carbon, and nitrogen. Analyses left to complete are gross energy, acid detergent lignin, and ether extract. An in vitro trial was run in triplicate using the same diets as in the calorimetry trial. Total gas production, and methane and carbon dioxide CO2 production were measured. Diet samples from the in vitro analysis were analyzed for in vitro dry matter digestibility, in vitro neutral detergent fiber digestibility, and in vitro acid detergent fiber digestibility. Managing soil and manure nitrogen, phosphorus and carbon can improve soil properties, reduce nutrient loss and mitigate pathogens and antibiotic resistant bacteria. The goal was to develop an assay to detect antibiotic resistance in agricultural production settings. A multiplex polymerase chain reaction (PCR) assay was designed to detect four different genes associated with antibiotic resistance. The genes of interest were sul1 (sulfonamide resistance), ermB (erythromycin resistance), CTX-M (beta-lactamase resistance) and intI1 (integrase – a gene that helps facilitate the incorporation of resistance genes into the bacterial DNA). A combination of existing primers, modified existing primers, and newly designed primers were used in the assay. A method called touchdown PCR was used to increase primer specificity which decreased the occurrence of non-specific bands. Using a multiplex PCR to screen for several genes at once saves time and reagents. The assay was applied to gBlocks (synthetic genes that act as a positive control), a reference set of 300 E. coli isolates, and community DNA extractions from environmental samples. A student assigned to the Bushland lab was trained in the assay procedures. In a collaborative study with the location's Soil and Water Management Research Unit, we investigated soluble carbon quality and quantity in agricultural soils under long-term (45 years) conservation management or traditional management, as compared to native rangeland. We used ultraviolet-visible and Fourier-transform infrared spectroscopies to characterize forms and complexity of soluble carbon. This research indicated that the majority of soluble carbon from native grassland was lost as carbon dioxide within a few years after conversion to rangeland. There were no major improvements in soil carbon status with conservation management, despite increased crop yields. This indicated that the correlation between soil health and soil carbon in dryland systems is poorly understood. Soil type influences the fate of phosphorus after manure application: in collaboration with ARS from Auburn, Alabama, we used sequential fractionation and phosphatase hydrolysis to evaluate the plant availability in soils that contained high levels of aluminum and iron. These soils had received poultry manure fertilization for 12 years at different rates.
1. Nitrous oxide emissions from beef cattle feedyards increase considerably above 88 degrees Fahrenheit. Nitrous oxide is a greenhouse gas that contributes to global warming and climate change. High concentrations of nitrogen and carbon make livestock manure at beef feedyards a source of nitrous oxide emissions. While the effects of rainfall on nitrous oxide emissions have been studied intensively, little is known about the effects of other variables like temperature. Therefore, scientists from USDA-ARS in Bushland, Texas and Clay Center, Nebraska and Texas A&M AgriLife Research in Amarillo, Texas, studied how temperature affects nitrous oxide emissions from beef cattle feedlot manure. Nitrous oxide emissions were monitored after rainfall at eight manure temperatures ranging from 41 to 115 degrees Fahrenheit, representative of winter and summer maximum temperature extremes. Nitrous oxide emissions increased with increasing temperature, with a sharp jump in emissions above 88 degrees Fahrenheit. Air temperature is difficult to control in a feeding pen. Therefore, the practical recommendation is to keep feedlot pens dry, especially during the hot summer months, to reduce nitrous oxide emissions.
2. New techniques improve measurements of beef cattle feeding and emissions. There is a growing concern over the effects of livestock production on the environment. However, techniques for monitoring environmental impacts are still evolving since this is a relatively new field of research. Therefore, scientists from USDA-ARS in Bushland, Texas, Texas A&M AgriLife Research, and New Mexico State University summarized the existing technologies used for conducting research on the environmental impacts of feeding beef cattle. These technologies include methods for measuring feed intake and methane emissions from individual animals, measuring greenhouse gas and ammonia emissions from manure, and identifying potential pathogens in manure. It is critical that new technologies are validated for accuracy. Awareness of existing technologies expands the toolkit that researchers have available to increase understanding of the environmental impacts of cattle production.
3. Ground soybean hulls reduce swine manure odors. Odors from confined animal feeding operation can be a nuisance to neighbors. Ground soybean hulls contain a naturally occurring enzyme called soybean peroxidase, which has been shown to reduce odors from swine manure. However, this technology has only been tested in the laboratory. Therefore, a farm-scale experiment was conducted by scientists from Iowa State University and ARS in Bushland, Texas to evaluate the effects of ground soybean hulls on odors from swine manure under field conditions. The chemicals most responsible for swine odor were reduced by 36 to 80 percent. The total treatment cost, including materials and labor, was $2.62 per marketed pig. These results give swine producers and consultants a cost effective way to reduce odors.
4. Composted manure improves soil health. Most crops require relatively high levels of nutrients for optimum yields, and most soils contain insufficient nutrients to sustain maximum crop production. However, land applications of raw beef manure and compost increase soil nutrients. The Texas Northern High Plains produces 17 million tons of beef cattle manure annually; therefore, the region has an abundant supply of cattle manure. Because of the high cost of transporting manure, feedyard operators and farmers have become interested in the benefits of aerobic composting. Therefore, scientists from USDA-ARS in Bushland, Texas, Texas A&M AgriLife Research, and Illinois State University conducted a two-year field study to compare raw manure, composted manure, and commercial fertilizers when applied to corn. Corn yields were similar for all three fertilizer treatments and the plots receiving composted manure had 10 to 14 percent higher soil organic matter content. Land application of composted manure provides benefits to soil health and sustainability in the region.
Parker, D.B., Todd, R.W., Waldrip, H., Webb, K., Willis, W.M., Meyer, B.E., Marek, G.W., Casey, K.D., Auvermann, B., Marek, T., Pemberton, B. 2017. Improved chamber systems for rapid, real-time nitrous oxide emissions from manure and soil. Transactions of the ASABE. 60:(4)1235-1258. doi:10.13031/trans.1215a.
Maurer, D., Bruning, K., Koziel, J., Parker, D.B. 2017. Farm-scale testing of soybean peroxidase and calcium peroxide for surficial swine manure treatment and mitigation of odorous VOCs, ammonia and hydrogen sulfide. Atmospheric Environment. 166:467-478. doi:10.1016/j.atmosevn.2017.07.048.
Cole, N.A., Parker, D.B., Todd, R.W., Leytem, A.B., Dungan, R.S., Hales Paxton, K.E., Ivey, S., Jennings, J. 2018. Use of new techniques to evaluate the environmental footprint of feedlot systems. Translational Animal Science. 2:89-100. https://doi.org/10.1093/tas/txx001.
Parker, D.B., Waldrip, H., Casey, K.D., Woodbury, B.L., Spiehs, M.J., Webb, K., Willis, W.M. 2018. How do temperature and rainfall affect nitrous oxide emissions from open-lot beef cattle feedyard pens? Transactions of the ASABE. 61(3): 1049-1061. doi:10.13031/trans.12788.
Waldrip, H., Todd, R.W., Parker, D.B., Casey, K.D. 2017. Nitrous oxide emissions from southern high plains beef cattle feedyards: Measurement and modeling. Transactions of the ASABE. 60: 1209-1221. doi: 10.13031/trans.12085.
Parker, D.B., Venhaus, D., Robinson, C., Marek, T., Sweeten, J. 2018. Corn yield and soil fertility with combined use of raw or composted beef manure and inorganic fertilizers on the texas northern high plains. Compost Science and Utilization. doi:10.1080/1065657X.2017.1366376.