1a. Objectives (from AD-416):
1) Determine the factors that affect P transformations and transport in soil, water and manure. 1A. Utilize P runoff from 25 small watersheds to validate the Arkansas P index. 2) Determine the long-term impacts of grazing management and treating manure with alum on nutrient and water transport processes and air emissions. 2A. Determine the long-term effects of overgrazing, rotational grazing, haying, and buffer strips on nutrient and sediment runoff from pastures. 2B. Determine the long-term effects of treating poultry litter with alum on NH3 emissions, soil chemistry, P runoff and leaching, and forage yields. 3) Develop and evaluate best management practices to reduce non-point P pollution from poultry litter application on pasture land. 3A. Compare nutrient runoff and hydrology from small watershed fertilized with poultry litter using three different methods. 4) Determine ammonia emission rates from poultry litter and develop best management practices to control ammonia volatilization. 4A. Determine the effect of in-house composting of poultry litter on emissions of ammonia and greenhouse gases. 4B. Determine the efficacy of an NH3 scrubber on reducing the emissions of dust and NH3 from poultry houses. 4C. Determine the effect of alum additions to broiler litter on emissions of NH3, volatile organic compounds (VOCs), and dust. 5) Determine the sources and loss pathways of bacterial pathogens associated with animal manures and develop cost-effective best management practices (BMPs) to mitigate pathogen runoff. 5A. Measure pathogen and indicator organisms in runoff from 25 small watersheds fertilized with manure or biosolids. 5B. Determine the impact of BMPs on pathogen runoff from poultry litter. 6) Evaluate the risks and benefits of agricultural applications of municipal wastes (biosolids and water treatment residuals) and develop formulations and application methods that enhance the value of these resources while reducing negative environmental impacts.
1b. Approach (from AD-416):
Both long-term and short-term studies will be conducted. Two 20-year studies will be conducted to determine the long-term impacts of poultry litter, alum-treated litter, and ammonium nitrate on soil chemistry, nutrient runoff, and forage production. A long-term study (13 years) will also be conducted on the impacts of various pasture management strategies (overgrazing, rotational grazing, haying, etc.) on pasture hydrology, nutrient runoff, soil erosion, and forage production. Another long-term study (7 years) will be conducted to determine the effects of pasture renovation and litter incorporation on P runoff, ammonia emissions and forage yields. Pathogen runoff will also be evaluated from both small plots and at the field scale. Ammonia emissions will also be measured from commercial broiler houses using various management 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.
3. Progress Report:
During the past year our main focus has been on building and testing an ammonia scrubber for poultry houses. Trials were conducted using alum, aluminum chloride, calcium chloride, ferric sulfate, ferric chloride, sodium bisulfate, sulfuric acid, hydrochloric acid, phosphoric acid, nitric acid, and water. Although sulfuric acid appeared to be the most cost-effective acid, we have decided to use sodium bisulfate in the scrubber because it is safer than strong acids and is easy to manage. We also conducted research to determine the effect of different internal configurations on ammonia removal and on the amount of static pressure caused by the scrubber. During the past year we also discovered a novel method of lowering soluble arsenic levels in the soil solution of flooded rice soils. High levels of arsenic can build up in the grain of rice because it is grown under flooded conditions. Laboratory studies showed that additions of aluminum, iron, and manganese amendments to rice soils resulted in reductions of soluble arsenic in soil of up to 70%. The most effective amendment for this practice was aluminum sulfate (alum).
1. Method to reduce arsenic in rice. Arsenic accumulates in the grain of rice since it is grown under flooded conditions. Since arsenic is a known carcinogen, methods to lower arsenic in rice are needed. During the past year, researchers at Fayetteville, Arkansas, hypothesized that arsenic solubility could be lowered in flooded rice soils by adding aluminum, iron, or manganese amendments, which would lower arsenic uptake by rice. Laboratory studies showed that amendments, such as alum, lowered soluble arsenic by up to 70%. Small plot studies are currently underway in Stuttgart, Arkansas, to determine the effects of this treatment are on rice yields and arsenic uptake.
Moore Jr, P.A., Miles, D.M., Burns, R., Pote, D.H., Berg, K., Choi, I. 2011. Ammonia emissions factors from broiler litter in barns, storage, and after land application. Journal of Environmental Quality. 40:1395-1404.