NUTRIENT AND ?17-ESTRADIOL LOSS IN RUNOFF WATER FROM POULTRY LITTERS

Abstract

A main water quality concern is accelerated eutrophi- cation of fresh waters from nonpoint source pollution, particularly nutrient transport in surface runoff from agricultural areas and confined animal feeding operations. This study examined nutrient and β17-estradiol concentrations in runoff from small plots where six poultry litters were applied at a rate of about 67 kg/ha of total phosphorus (TP). The six poultry litter treatments included pellet- ed compost, pelleted litter, raw litter, alum (treated) litter, pelleted alum litter, and normal litter (no alum). Four replicates of the six poultry litter treatments and a control (plots without poultry litter application) were used in this study. Rainfall simulations at inten- sity of 50 mm/hr were conducted immediately following poultry lit- ter application to the plots and again 30 days later. Composite runoff samples were analyzed for soluble reactive phosphorus (SRP), ammonia (NH4), nitrate (NO3), TP, total nitrogen (TN) and β17-estradiol concentrations. In general, poultry litter applications increased nutrient and β17-estradiol concentrations in runoff water. Ammonia and P concentrations in runoff water from the first simu- lation were correlated to application rates of water extractable NH4 (R2 = 0.70) and P (R2 = 0.68) in the manure. Results suggest that alum applications to poultry litter in houses inbetween flocks is an effective best management practice for reducing phosphorus (P) and β17-estradiol concentrations in runoff and that pelleted poultry litters may increase the potential for P and β17-estradiol loss in runoff water. Inferences regarding pelleted poultry litters should be viewed cautiously, because the environmental consequence of pelleting poultry litters needs additional investigation. (KEY TERMS: water quality; poultry litter; nonpoint source pollu- tion; nutrients; estradiol; best management practices.)