Runoff Water Quality as Affected by Surface‐applied Dairy Cattle Manure

Abstract

Abstract The effect of dairy cattle manure on runoff water quality was determined. The manure was surface‐applied to Coastal bermudagrass ( Cynodon dactylon [L.] Pers.) on a Norfolk sandy loam with < 2% slope, at the rate of 45 metric tons/ha per year for 4 years in split applications. Manure applications slightly increased biochemical oxygen demand (BOD) values of runoff water; the maximum value was < 20 mg/liter and annual mean values were all < 10 mg/liter with no BOD buildup in the runoff water over the 4‐year period. Nitrate levels in runoff water were increased by the manure, but all annual mean values were below critical levels at < 8 mg NO 3 ‐N/liter. During the first 2 years, about 30 kg/ha total N was lost in runoff, but < 6 kg N/ha was lost during the third and fourth years.