Author
DELAUNE, PAUL - UNIVERSITY OF ARKANSAS | |
MOORE, PHILIP | |
LEMUNYON, J - USDA/NRCS |
Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 3/10/2006 Publication Date: 7/6/2006 Citation: Delaune, P.B., Moore Jr., P.A., Lemunyon, J.L. 2006. Effect of chemical and microbial amendments on phosphorus runoff from composted poultry litter. Journal of Environmental Quality. 35:1291-1296. Interpretive Summary: Many scientists have advocated composting manures, since this process results in the death of most pathogenic microorganisms present in manure. However, when manure is composted, a large quantity of the nitrogen is lost due to ammonia volatilization. The objectives of this study were to measure 1) phosphorus runoff and 2) forage yield and nitrogen uptake from small plots fertilized with composted and fresh poultry litter. Two composting studies, aerated using mechanical turning, were conducted in consecutive years. Composted litter was collected at the completion of each study for use in runoff studies. Treatments in runoff studies included an unfertilized control, fresh (uncomposted) poultry litter, and litter composted with: no amendment, phosphoric acid, alum, and a microbial mixture. An additional treatment, litter composted with alum plus the microbial mixture, was evaluated during the first year. Fertilizer treatments were applied at rates equivalent to 4 tons/acre and rainfall simulators were used to produce a 2" per hour storm event. Composted poultry litter had higher total phosphorus concentrations than fresh poultry litter, since some of the manure is lost through decomposition. Soluble reactive P concentrations were lowest in alum-treated compost, which reduced soluble P concentrations in runoff water by as much as 84%. Forage yields and nitrogen uptake were greatest from plots fertilized with fresh poultry litter. Composting poultry litter without the addition of leaves, hay or other carbon sources can increase phosphorus concentrations in the end product and surface runoff. Technical Abstract: Environmental impacts of composting poultry litter with chemical amendments in the absence of bulking agents at the field scale have not been well quantified. The objectives of this study were to measure 1) phosphorus (P) runoff and 2) forage yield and nitrogen (N) uptake from small plots fertilized with composted and fresh poultry litter. Two composting studies, aerated using mechanical turning, were conducted in consecutive years. Composted litter was collected at the completion of each study for use in runoff studies. Treatments in runoff studies included an unfertilized control, fresh (uncomposted) poultry litter, and litter composted with: no amendment, H3PO4, alum, and a microbial mixture. An additional treatment, litter composted with alum plus the microbial mixture, was evaluated during the first year. Fertilizer treatments were applied at rates equivalent to 8.96 Mg ha**-1 and rainfall simulators were used to produce a 5 cm hr**-1 storm event. Composted poultry litter, regardless of treatment, had higher total P concentrations than fresh poultry litter. Composting poultry litter resulted in reductions of N:P ratios by as much as 51%. Soluble reactive P concentrations were lowest in alum-treated compost, which reduced soluble P concentrations in runoff water by as much as 84%. Forage yields and N uptake was greatest from plots fertilized with fresh poultry litter. Composting poultry litter without the addition of C sources can increase P concentrations in the end product and surface runoff. This study also indicated that increased rates of composted poultry litter would be required to meet equivalent N rates supplied by fresh poultry litter. |