Comparing Model Estimation with Measured Ammonia Emission Data for Naturally Ventilated Dairy Cattle Buildings with Slatted Floor

摘要

Laboratory experiments were carried out in a wind tunnel with a model of a slurry pit to investigate the characteristics of ammonia emission from dairy cattle buildings with a slatted floor. Ammonia emission at different temperatures and air velocities over the floor surface above the slurry pit was measured with uniform feces spreading and urine sprinkling on the surface daily. The data were used to improve a model for estimation of ammonia emission from dairy cattle buildings. Estimation results from the updated emission model were compared with measured data from 5 naturally ventilated dairy cattle buildings. The overall measured ammonia emission rates were in the range of 10 - 56 g/day per cow at air temperatures of 2.3 - 22.4 °C. The model simulated emission rates were in the range of 8 - 65 g/day per cow for the surveyed buildings. The average simulated ammonia emission rate was 15.6% higher than the mean measured value. An example of simulated and measured ammonia emission patterns for a 24-hour period is given.