Submitted to: Better Crops
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/15/1998
Publication Date: N/A
Interpretive Summary: An effective management practice to reduce phosphorus (P) concentrations in runoff identified in recent research is the practice of adding aluminum sulfate (alum) to poultry litter. Runoff studies at the University of Arkansas have shown that P concentrations in runoff from plots treated with alum-treated litter were 87% lower than plots treated with untreated litter. Soil studies have shown that plots treated with alum-treated litter for three years do not have significantly higher soil test P values than plots which received no fertilizer. Additional runoff studies showed that using alum-treated litter can reduce concentrations of As, Cu, Fe, and Zn in runoff. Besides environmental benefits, alum-addition to poultry litter can result in economic benefits to growers. Studies at commercial broiler farms indicated that alum treatment reduces ammonia volatilization thereby increasing the weights of the birds, lowering mortality, and reducing energy costs.
Technical Abstract: An effective management practice to reduce phosphorus (P) concentrations in runoff identified in recent research is the practice of adding aluminum sulfate (alum) to poultry litter. Laboratory studies have shown that the addition of alum to poultry litter is extremely effective in decreasing the P solubility of poultry litter. Consequently, several field studies were conducted at the Agricultural Experiment Station of the University of Arkansas to compare the differences in runoff P and soil test P of tall fescue plots treated with untreated poultry litter and alum-treated poultry litter. One study that focused on runoff quality showed that soluble reactive P concentrations in runoff water were 87% lower from alum-treated litter plots compared to untreated litter plots. Another study showed that after three years of poultry litter applications, plots receiving alum-treated litter did not have significantly higher soil test P values than plots that received no fertilization. This study also showed that plots which received untreated litter had significantly higher soil test P values when compared to plots treated with alum-treated litter. Alum-treated litter has also been evaluated on a field scale level. Two 0.45 ha watersheds were constructed and instrumented with automatic water samplers on a local commercial broiler farm in northwest Arkansas. One watershed was fertilized with alum-treated litter, the other with untreated litter. Soluble reactive P concentrations in the runoff from the watershed treated with alum-treated litter were much lower than the runoff from the watershed treated with untreated litter.