Estimating ammonia loss from sprinkler-applied swine effluent

Volatilization of NH3 from sprinkler-applied effluent is a major N loss pathway in the Great Plains region, but there is disagreement as to how much of the total NH4-N applied in effluent is lost. The objectives of the study were to determine NH3 loss during sprinkler application and from soil and to determine the amount of mineral N available to the crop over a series of swine effluent application rates, effluent sources, and field conditions. A 3-yr study was conducted on fields near swine (Sus scrofa) production operations. A mass balance method was used to estimate N loss during and after effluent application at rates of 1.3, 1.9, and 2.5 cm. Change in inorganic N concentration in effluent captured below the sprinkler was used to estimate volatilization during application, and the change in inorganic N concentration in soil (before and 72 h after application) was used to estimate N loss from soil. Ammonia loss during application ranged from 8 to 27% of the total NH4-N in the effluent due to drift and volatilization. The range of estimated N loss from the soil varied from 24 to 56% of the NH4-N in the applied effluent. The total N loss from both the sprinkler application and the soil ranged from 32 to 83%, with an average loss of approximately 58%. Effluent N concentration did not significantly impact the percent of N lost, while air temperature and wind speed were significant variables in the percent of N lost.