Submitted to: Journal of Environmental Quality
Publication Type: Peer reviewed journal
Publication Acceptance Date: 11/1/2003
Publication Date: 3/1/2004
Citation: Delaune, P.B., Moore Jr, P.A., Daniel, T.C., Lemunyon, J.L. 2004. Effect of chemical and microbial amendments or ammonia emissions from composting poultry litter. Journal of Environmental Quality. 33:728-734. Interpretive Summary: Chemicals such as aluminum sulfate and phosphoric acid can reduce the amount of nitrogen (N) lost from composting poultry litter. The objectives of this study were to: 1) measure the amount of N lost from composting poultry litter and 2) evaluate methods that could reduce the loss of N as a gas from composting poultry litter. Poultry litter was composted for two years, 68-d in year one and 93-d in year 2. Each year, alum, phosphoric acid, and a microbial mixture were added to each compost row, along with a row that received no treatment. Compost treated with alum and phosphoric acid had the lowest N loss rates. As a result of lower N loss rates, N levels were higher in compost treated with alum and phosphoric acid. Poultry litter, which was not composted (fresh litter), as well as each compost treatment were applied to grass plots. Plots fertilized with fresh poultry litter had higher yields than all of the compost treatments since the fresh litter was not composted and N levels were higher in the fresh litter. Since it takes time and money to compost poultry litter and fertilizer N is lost during composting, it is not profitable to compost poultry litter when compared to using fresh poultry litter as a fertilizer.
Technical Abstract: Research has shown that aluminum sulfate (alum) and phosphoric acid greatly reduce ammonia (NH3) volatilization from poultry litter; however, no studies have yet reported the effects of these amendments on field-scale composting of poultry litter. The objectives of this study were to: 1) quantify NH3 volatilization from composting litter by measuring both NH3 emissions and changes in total nitrogen (N) in the litter; and 2) evaluate potential methods of reducing NH3 losses from composting poultry litter. Poultry litter was composted for 68-d the first year and 92-d the second year. Eleven treatments were screened in year one, which included an unamended control, a microbial mixture, a microbial mixture with 5% alum incorporated into the litter, 5% and 10% alum rates either surface applied or incorporated, and 1% and 2% phosphoric acid rates either surface applied or incorporated. Treatments in year two included an unamended control, a microbial mixture, alum (7% by fr. wt.), and phosphoric acid (1.5% by fr. wt.). Alum and phosphoric acid reduced NH3 emissions from composting poultry by as much as 76% and 54%, respectively. The highest NH3 emission rates were from microbial treatments each year. Compost treated with chemical amendments retained more initial N than all other treatments. Fertility trials were conducted with each of the compost types as well as fresh litter. Fresh litter applications resulted in higher forage yields and N uptake levels than all compost treatments. Due to the cost and N loss associated with composting poultry litter, composting is not economical from an agronomic perspective compared to fresh poultry litter.