RUNOFF WATER-QUALITY AS AFFECTED BY SURFACE-APPLIED DAIRY-CATTLE MANURE

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 NO3-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.; The effect of dairy cattle manure on runoff water quality was determined. The manure was surface-applied to Coastal bermudagrass on a Norfolk sandy loam with less than 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 less than 20 mg/liter and annual mean values were all less than 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 less than 8 mg NO//3-N/liter. During the first 2 years, about 30 kg/ha total N was lost in runoff, but less than 6 kg N/ha was lost during the third and fourth years.