DRYING INTERVAL EFFECTS ON QUALITY OF RUNOFF FROM FESCUE PLOTS TREATED WITH POULTRY LITTER

Land application of poultry (Gallus gallus domesticus) litter can lead to elevated runoff concentrations of organic matter and nutrients. Th is experiment was conducted to determine the impacts of poultry litter treatment (0 and 218 kg of N ha-1) and drying interval (4, 7, and 14 days) between litter application and simulated rainfall on quality of runoff from fescue grass (Festuca arundinacea Schreb.) plots. Runoff w as generated from simulated rainfall (50 mm h-1) and sampled at 0.08-h intervals during runoff. Composite runoff samples from each treatment and replication were analyzed for nitrate N (NO3-N), ammonia N (NH3-N ), total Kjeldahl N (TKN), ortho-P (PO4-P), total P (TP), chemical oxy gen demand (COD), and total suspended solids (TSS). One set per treatm ent of the noncomposited runoff samples was also analyzed Runoff conce ntrations of all parameters except NO3-N were significantly (p < 0.05) higher for the litter-treated plots than for the control plots. Dryin g interval did not significantly (p < 0.05) affect either concentratio n or total mass of any constituent lost in the runoff. Concentrations of NH3-N, TKN, PO4-P, and TP decreased uniformly with increasing runof f rate and thus with time after beginning of runoff. Temporal variatio n in runoff concentrations of NO3-N, COD, and TSS followed no identifi able general pattern.