Water-quality effects of infiltration rate and manure application rate forsoils receiving swine manure

We investigated the effects of rain infiltration rate and manure applicatio n rate on the quality of leachate and runoff from four soils. Tall fescue ( Festuca arundinacea Schreber) plots received swine (Sus scrofa L) manure sl urry at 1 or 2 Mg (dry weight) ha(-1) to provide N at 78.4 or 156.8 kg ha(- 1). Simulated rain (75 mm hr(-1)) applied 24 hr after slurry application pr oduced 30 min of runoff from each plot. Mean infiltration rates ranged from 7.7 to 60.6 mm hr(-1). Concentrations and mass losses of total Kjeldahl ni trogen (TKN), NH4-N, dissolved reactive P (DRP), and total P in runoff incr eased significantly (alpha = 0.05) following slurry applications, and doubl ed when slurry application doubled. High infiltration rates reduced runoff volumes and runoff concentrations of Cl, total dissolved solids, DRP, TKN, and NH4-N. Concentrations of NO3-N and NH4-N in leachate water, collected a t 0.4 m depth by suction cup lysimeters, did not increase following slurry applications.