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 (i) evaluate NH₃ volatilization from composting litter by measuring both NH₃ volatilization and changes in total nitrogen (N) in the litter and (ii) 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 1, 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 2 included an unamended control, a microbial mixture, alum (7% by fresh wt.), and phosphoric acid (1.5% by fresh wt.). Alum and phosphoric acid reduced NH₃ volatilization from composting poultry litter 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. Due to the cost and N loss associated with composting poultry litter, composting is not economical from an agronomic perspective compared with the use of fresh poultry litter.

Copyright © 2004. American Society of Agronomy, Crop Science Society of America, Soil Science Society. ASA, CSSA, SSSA