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ARS Home » Southeast Area » Fayetteville, Arkansas » Poultry Production and Product Safety Research » Research » Publications at this Location » Publication #321978
Title: Reducing phosphorus runoff and leaching from poultry litter with alum: Twenty-year small plot and paired-watershed studies

Author
item HUANG, LIDONG - Nanjing Tech University
item Moore, Philip
item Kleinman, Peter
item Elkin, Kyle
item SAVIN, MARY - University Of Arkansas
item Pote, Daniel
item EDWARDS, DWAYNE - University Of Kentucky

Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/21/2016
Publication Date: 6/24/2016
Citation: Huang, L., Moore Jr, P.A., Kleinman, P.J., Elkin, K.R., Savin, M., Pote, D.H., Edwards, D. 2016. Reducing phosphorus runoff and leaching from poultry litter with alum: Twenty year small plot and paired-watershed studies. Journal of Environmental Quality. 45:1413-1420.

Interpretive Summary: Alum additions to poultry litter reduce ammonia (NH3) emissions and phosphorus (P) runoff losses. The goal of this long-term (20 year) study was to evaluate the effects of alum-treated and untreated poultry litter applications on P leaching and runoff under pasture conditions. Litter applications were made annually in a paired watershed study and a small plot study from 1995 to 2015. The paired watershed experiment evaluated P losses from alum-treated or untreated litter in a side by side comparison. There were 13 treatments in the small plot study (unfertilized control, four rates of alum-treated litter, four rates of untreated litter and four rates of ammonium nitrate). Soil test phosphorus (Mehlich III P and water extractable P) levels were measured annually in both studies. Results showed that on average alum-treated litter addition resulted in higher Mehlich III P (M3-P) and lower water extractable P (WEP) than normal litter at the surface. At year 20, the M3-P in the top 10 cm of soil fertilized with the highest rate of alum-treated litter (705 kg P/ha) was much higher than that with untreated litter (471 kg P/ha) when analyzed using ICP. However, the differences in surface soil M-3 values were much less when the extracts were analyzed using colorimetric methods, indicating that alum additions affected organic P availability. Mehlich-3 P at lower depths was 266% greater in plots fertilized with untreated litter, than alum-treated litter; indicating alum greatly reduced P leaching. Annual P loads in runoff were 231% higher from untreated litter than alum-treated litter in the paired watershed study. These two 20-year studies provide further evidences that alum is an effective additive that can reduce both surface P runoff and P leaching from poultry litter.

Technical Abstract: Treating poultry litter with alum is a best management practice (BMP) for lowering ammonia (NH3) emissions and phosphorus (P) runoff losses. The objective of this study was to evaluate the long-term (20 year) effects of alum-treated and untreated poultry litter applications on P availability, leaching and runoff under pasture conditions. Litter applications were made annually in a paired watershed study and a small plot study from 1995 to 2015. The paired watershed experiment evaluated P losses from alum-treated or untreated litter in a side by side comparison. There were 13 treatments in the small plot study (unfertilized control, four rates of alum-treated litter, four rates of untreated litter and four rates of NH4NO3). Mehlich III P (M3-P) and water extractable P (WEP) in soil were determined annually in both studies prior to litter applications. Results showed that on average alum-treated litter addition resulted in higher M3-P and lower WEP than normal litter at the surface. At year 20, the M3-P in the top 10 cm of soil fertilized with the highest rate of alum-treated litter (705 kg P/ha) was much higher than that with untreated litter (471 kg P/ha) when analyzed using ICP. However, the differences in surface soil M-3 values were much less when the extracts were analyzed using colorimetric methods, indicating that alum additions affected organic P availability. Mehlich-3 P at lower depths (10-50 cm) was 266% greater in plots fertilized with untreated litter (373 kg P/ha), than alum-treated litter (140 kg M3-P/ha); indicating alum greatly reduced P leaching. Annual P loads in runoff were 231% higher from untreated litter (1.87 kg P/ha) than alum-treated litter (0.81 kg P/ha) in the paired watershed study. These two 20-year studies provide further evidences that alum is an effective additive that can reduce both surface P runoff and P leaching from poultry litter.