The goal of this project is to reduce the negative environmental impacts of poultry litter on air, soil and water resources, while improving the agronomic value of this resource. We will measure runoff losses from pastures and aerial emissions from poultry facilities and develop/test Best Management Practices (BMPs) to reduce these losses. We will also measure the potential sources of acidification of the Mulberry River. The objectives of this research are: Objective 1. Quantify and track losses of nutrients, metals, soil and pathogens from pastures fertilized with poultry manure and develop and test management practices that reduce water quality impacts. Sub-objective 1A. Determine the long-term effects of overgrazing, rotational grazing, haying, and buffer strips on nutrient and sediment runoff from pastures. Sub-objective 1B. Determine the long-term effects of alum-treated and normal poultry litter applications on legacy P in soils, and on soil chemistry, P runoff and P leaching. Sub-objective 1C: Compare nutrient and pathogen runoff from small watersheds fertilized with poultry litter that is applied using litter incorporation or by broadcasting. Sub-objective 1D. Utilize P runoff from 24 small watersheds to validate the Arkansas P index. Objective 2. Measure gaseous and particulate emissions from poultry houses and develop and test management practices to reduce air pollution and nutrient losses. Sub-objective 2A. Measure NH3, dust and greenhouse gas concentrations and emissions from poultry houses. Sub-objective 2B. Determine the efficacy of an NH3 scrubber on reducing the emissions of dust and NH3 from poultry houses. Sub-objective 2C. Measure forage growth, N uptake and P runoff from small plots fertilized with N-rich scrubber solutions and commercial N fertilizer. Sub-objective 2D. Develop/test a cost-effective litter amendment that reduces NH3 emissions and P runoff. Objective 3. Quantify amounts of acid generated from different sources in the Mulberry River Watershed. Sub-objective 3A. Measure atmospheric NH3 and wet deposition of acid in the Mulberry River watershed. Sub-objective 3B. Compare various measures of soil acidification under hardwood and pine forests at multiple paired locations within the Mulberry River Watershed. Sub-objective 3C. Evaluate the relationship between water chemistry and the percentage of forest in pines within several sub-watersheds of the Mulberry River.
The objective of this research is to reduce the negative environmental impacts of poultry litter on air, soil and/or water resources, while improving the agronomic value of this resource. To meet this goal we propose to conduct research which investigates the nature of problems associated with poultry litter, determines the extent of these problems, and provides solutions to them. Both long-term and short-term studies will be conducted. One of the long-term (20 year) studies initiated in 2003 utilizes 15 small watersheds to determine the impacts of pasture management strategies (over grazing, rotational grazing, buffer strips, riparian buffer strips and haying) on pasture hydrology, erosion and nutrient and pathogen runoff. Another watershed study will evaluate the effect of two litter application methods on nutrient runoff. Two other long-term studies (paired watershed and small plot study) initiated in 1995 will evaluate the legacy effects of fertilizing with normal poultry litter or litter treated with alum on phosphorus (P) runoff and leaching. The watershed studies described above will also be utilized to validate the Arkansas P Index. Experiments will be conducted to evaluate the effectiveness of ammonia (NH3) scrubbers on reducing NH3 and dust emissions from poultry houses. Research will be conducted in the Mulberry River Watershed to determine if river acidification is occurring because of atmospheric NH3 deposition or other causes, such as acid rain or forestry practices. The ultimate goal of this research is to develop cost-effective best management practices (BMPs) for poultry manure management which improve air and water quality.
Under Objective A.1, we made progress in conducting research aimed at reducing pathogens and antibiotic resistance. Manure from animals treated with antibiotics is an abundant source of valuable nitrogen and phosphorus, may also contain antimicrobial resistant (AMR) bacteria and residues. The persistence of AMR in the soil-water environment is of significant public health concern, yet the fate, transport pathways, and interaction of antimicrobials with the soil microbiome is poorly understood. During the past year we initiated a series of studies to evaluate the movement and fate of AMR bacteria in animal waste and runoff samples stored from a long-term (13 year +) study based on pasture management. This research was funded via an ARS AMR Funding Opportunity, “Effects of Conservation Pasture Management on Antimicrobial Resistance Bacteria in Water and Soil Systems: Longitudinal Analysis of Samples Collected over 13 Years.” An additional year of funding was procured through this program for “Evaluating Mitigation Strategies for the Reduction of Antimicrobial Resistance Gene Transfer from Animal Hosts to the Environment.” These results will be useful for identifying best management practices for reducing the AMR movement in soil and water systems for enhancing soil health and biodiversity for sustainable animal production and disease management. One of biggest research efforts this year has been to try to determine the cause of the acidification of the Mulberry River; one of the Nation’s Wild and Scenic Rivers which is located in Arkansas in the Ozark mountains. Scientists at the Fayetteville, Arkansas unit have been measuring ammonia concentrations in the atmosphere in the Mulberry Watershed for almost 3 years since nitrification of ammonia in soils can cause acidification. However, the levels of atmospheric ammonia are very low; about 1 ppb. Therefore it is doubtful ammonia is causing acidification. We have also been measuring acid rain and it is not that acidic, so probably is not the cause. A study was completed in the Mulberry Watershed in which many different measures of soil acidification were measured under hardwood and pine forests at ten paired locations within the Mulberry Watershed. Although pine straw was much more acidic than oak leaves at 7 of 10 sites, overall there were no differences in soil pH. Hence, it does not appear that converting hardwood forest to pine is causing acidification. We are also looking at fracking of gas wells to see if that is causing acidification. Fracking can cause pyrite oxidation, which leads to the formation of sulfuric acid in groundwater.
1. Treating poultry litter with alum reduces phosphorus leaching. Although adding alum to poultry litter is a well-known best management practice (BMP) for reducing ammonia emissions and phosphorus runoff, scant information is available on the effects of treating poultry litter with alum on phosphorus leaching. ARS researchers at Fayetteville, Arkansas, found that treating poultry litter with alum lowers phosphate leaching by 86%. Research was conducted on intact soil cores taken from a small plot study that had been ongoing for 20 years. Cores from 52 plots were exposed to natural rainfall, and phosphorus leaching was measured for one year. At the highest litter rate (four tons/acre), alum reduced total phosphorus concentrations in leachate by 80% and the total mass of phosphorus leached by 86%, compared with untreated litter. Currently over a billion broiler chickens are grown with alum each year in the U.S. with an economic impact of $10-20 million while improving air and surface water quality. In many parts of the country where soils are sandy, such as Delmarva, poultry litter applications are limited because of phosphorus leaching rather than surface runoff of phosphorus. This study demonstrated that alum greatly also reduces the risk of phosphorus leaching, which will enable growers in such areas to utilize this valuable fertilizer resource.
2. Quantifying environmental and economic effects of fertilizers for switchgrass biofuel production. Under the Energy Independence and Security Act and the Renewable Fuel Standard, 36 billion gallons of biofuels must be produced by 2022– more than twice the current level. Temporal patterns of biofuel crop growth, composition, and nutrient removal impact the development of models for predicting optimal harvest times and nutrient inputs for large-scale sustainable bioenergy production. ARS researchers at Fayetteville, Arkansas, completed a series of experiments this year evaluating the environmental impact and economic feasibility based on input cost-specific fertilizer recommendations for growing switchgrass in the mid-South. Overall, poultry litter was a less expensive source of fertility than synthetic fertilizer for biomass production, and thereby lowered the breakeven price. This research allowed for the development of models for predicting intra-seasonal changes and nutrient cycling for simulating productivity trade-offs and applying those to economic and environmental analyses for sustainable bioenergy production. Breakeven prices can be reduced by nearly 50% per acre with the use of poultry litter compared to inorganic inputs for the emerging biofuel economy.
Martin, J.W., Moore Jr, P.A., Hong, L., Ashworth, A.J., Miles, D.M. 2018. Effects of land-applied ammonia scrubber solutions on yield, nitrogen uptake, soil test phosphorus and phosphorus runoff. Journal of Environmental Quality. 47(2):263-269.
Abdala, D.B., Moore Jr, P.A., Rodrigues, M., Herrera, W., Pavinato, P.S. 2018. Long-term effects of alum-treated litter, untreated litter and NH4NO3 application on phosphorus speciation, distribution and reactivity in soils using K-edge XANES and chemical fractionation. Journal of Environmental Management. 213:201-216.
Anderson, K.R., Moore Jr, P.A., Miller, D.M., DeLaune, P.B., Edwards, D.R., Kleinman, P.J., Cade-Menun, B.J., Miles, D.M. 2018. Phosphorus leaching from soil cores from a twenty-year study evaluating alum treatment of poultry litter. Journal of Environmental Quality. 47:530-537.
Maguey, J., Michel, M.A., Baxter, M., Tellex, Jr, G., Moore Jr, P.A., Solis-Cruz, B., Hernandez-Patlan, D., Merino-Guzman, R. 2018. Effect of humic acids on intestinal viscosity, leaky gut and ammonia excretion in a 24 h feed restriction model to induce intestinal permeability in broiler chickens. Animal Science Journal. 89:1002-1010. https://doi.org/10.1111/asj.13011.
Moore Jr., P.A., Li, H., Burns, R., Miles, D.M., Maguire, R., Ogejo, J., Reiter, M., Buser, M., Trabue, S.L. 2018. Development of the ARS air scrubber: A device for reducing ammonia, dust and odor in exhaust air from animal rearing facilities. Frontiers in Sustainable Food Systems. 2:1-10.
Lindsay, K.R., Popp, M.P., West, C.P., Ashworth, A.J., Rocateli, A.C., Farris, R., Kakani, G., Fritschi, F.B., Green, S.V., Alison, M.W., Mawg, M.J., Acosta-Gamboai, L. 2017. Predicted harvest time effects on switchgrass moisture content, nutrient concentration, yield, and profitability. Biomass and Bioenergy. 108:74-89. https://doi.org/10.1016/j.biombioe.2017.09.017.
Ashworth, A.J., DeBruyn, J.M., Allen, F.L., Radosevick, M., Owens, P.R. 2017. Microbial community structure is affected by cropping sequences and poultry litter under long-term no-tillage. Soil Biology and Biochemistry. 114:210-219.
Ashworth, A.J., Allen, F.L., Bacon, J.L., Sams, C.E., Tyler, D.D., Grant, J.F., Moore Jr, P.A., Pote, D.H. 2017. Switchgrass cultivar, yield, and nutrient removal responses to harvest timing. Agronomy Journal. 109(6):2598-2605. Available: https://dl.sciencesocieties.org/publications/aj/articles/109/6/2598.
Bullock, E.L., Edwards, D.R., Moore Jr, P.A., Gates, R.S. 2016. Effects of chemical amendments to swine manure on runoff quality. Transactions of the ASABE. 59(6):1651-1660.
Ashworth, A.J., Allen, F.L., Owens, P.R., Debruyn, J.M., Sams, C. 2018. Crop rotations and poultry litter affect dynamic soil chemical properties and soil biota long-term. Journal of Environmental Quality. 47(6):1327-1338. https://doi.org/10.2134/jeq2017.12.0465.
Ashworth, A.J., Toler, H.D., Allen, F.L., Auge, R.M. 2018. Global meta-analysis reveals agro-grassland productivity varies based on species diversity over time. PLoS One. 13(7):e0200274. https://doi.org/10.1371/journal.pone.0200274.