Environmental impacts of the use of poultry manure for agricultural production systems

Excessive use of poultry manure (PM) on croplands is likely to affect the quality of surface and groundwater resources. A three-year study (1998–2000) was conducted on nine 0.4-ha plots and on six 2.1-m2 lysimeters to: (1) determine the movement of nitrate-nitrogen (NO3-N), orthophosphate (PO₄-P), Escherichia coli, fecal coliform, and fecal streptococcus with surface runoff and subsurface drain water from plots and lysimeters treated with 168 kgN/ha from urea ammonium nitrate (UAN) fertilizer, and 168 and 336 kg-N/ha from PM, and (2) predict the impacts of PM and UAN fertilizer application on NO₃-N losses with subsurface water using GLEAMS model.; The results of this study show that use of PM in field plots resulted in significantly higher corn and soybean yields when compared with commercial N fertilizer. The N application rate of 336 kg-N/ha from PM resulted in the highest NO₃-N and PO₄-P concentrations in subsurface drain water in comparison with the N application rates of 168 kg-N/ha from UAN and 168 kg-N/ha from PM. The 336 kg-N/ha N application rate from PM resulted in higher concentration of PO₄-P in surface runoff in comparison with the N application rate of 168 kg-N/ha. The N application rate of 336 kg-N/ha from PM resulted in higher concentrations of fecal streptococcus, Escherichia coli, and fecal coliform bacteria in surface and subsurface drain water in comparison with N application rate of 168 kg-N/ha from PM or UAN. This study shows that excessive use of PM (at an application rate of 336 kg-N/ha) is likely to increase pollution potential of water resources with nutrients and bacteria.; The GLEAMS model was capable of simulating subsurface drain flow from 168UAN, 168PM, and 336PM treatments. The model predicted overall NO₃ -N concentration in subsurface drain water from lysimeters under 168UAN, 168PM, and 336PM treatments reasonably well, giving mean differences of −0.43, −0.10, and −0.15 mg/L, respectively. The results show that there were no significant differences (P = 0.05) between measured and simulated NO₃-N losses with drainage water from 168UAN, 168PM, and 336PM treatments. These results show that GLEAMS model can be used as a viable management and decision-making tool to assess impacts of alternative N application treatments.