Ammonia emission and moisture evaporation from cattle manure with different moisture and excrement content

Abstract

Ammonia emission and moisture evaporation from manure affect the climate inside the cow barn. According to our previous study, the manure surface area is of greater importance than its layer thickness in this respect. However, in practice, the manure passage area cannot be reduced in the loose housing of cows in cubicles. Therefore, other factors contributing to emission abatement are to be considered. The study objective was to identify the relation between the ammonia emission and moisture evaporation from cattle manure and the manure moisture and excrement content. For this purpose, a laboratory-scale set-up was designed. It consisted of a case with a fan installed and an exhaust pipe with a gas detector and an air velocity transmitter. The initial relative moisture content of cow excrement was 89 %. Peat with 57 % moisture content was added to reduce it, and tap water was added to increase it. The mass of each sample was 1 kg. In the experiment, the tested sample was placed in the set-up; the air was blown over its surface by the fan and the sensors in the pipe recorded the ammonia concentration and the airflow rate. Each experiment lasted for 30 minutes. The ammonia emission was calculated by the common methodology. The moisture evaporation was determined by the change in the sample mass during the experiment. The study results showed that the average ammonia emission from the initial excrement with 89 % moisture content was 68.26 mg•h -1 . When peat was added and the mixture moisture content reduced to 84 %, the average ammonia emission was 41.57 mg•h -1 . When water was added and the mixture moisture content increased to 94 %, the average ammonia emission was 32.93 mg•h -1 . In terms of the excrement unit, the ammonia emission decreased by 30.1 % when peat was added and only by 9 % when water was added. Therefore, the animal housing on bedding is preferable to reduce the ammonia emission from manure and to create a more favorable climate in the cow barn.