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. This 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 was 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 oxygen demand (COD), and total suspended solids (TSS). One set per treatment of the noncomposited runoff samples was also analyzed. Runoff concentrations of all parameters except NO3-N were significantly (p < 0.05) higher for the litter-treated plots than for the control plots. Drying interval did not significantly (p < 0.05) affect either concentration or total mass of any constituent lost in the runoff. Concentrations of NH3-N, TKN, PO4-P, and TP decreased uniformly with increasing runoff rate and thus with time after beginning of runoff. Temporal variation in runoff concentrations of NO3-N, COD, and TSS followed no identifiable general pattern.