POTENTIAL RUNOFF QUALITY EFFECTS OF POULTRY MANURE SLURRY APPLIED TO FESCUE PLOTS

A 3¥2 factorial experiment was conducted to determine how quality of runoff from grassed areas amended with poultry manure slurry is affected by slurry application rate and rainfall intensity for storms occurring one day following application. Poultry manure slurry was applied at rates of 0, 220, and 879 kg N ha–1 to plots established with fescue grass on a Captina silt loam soil. Simulated rainfall was applied 24 h following slurry application at intensities of 5 and 10 cm h–1 until runoff had occurred for a duration of 0.5 h. Flow-weighted composite runoff samples were collected and analyzed for total Kjeldahl N, ammonia N, nitrate N, total P, dissolved reactive P, chemical oxygen demand, total suspended solids, and electrical conductivity. Effects of the experimental variables on both runoff concentrations and mass losses of slurry constituents were assessed by analyses of variance. Increasing slurry application rate significantly increased runoff concentrations of all slurry constituents investigated except nitrate N. For the affected slurry constituents, the relationships between runoff concentration of the constituent and slurry application rate appeared to be linear over the range of application rates used. Mass losses of all slurry constituents except nitrate N significantly increased with increases in both slurry application rate and rainfall intensity. Relationships between mass losses and slurry application rate also appeared to be linear for the range of application rates used in the study.