AERATION EFFECT ON NITROGENOUS EMISSIONS DURING THE COMPOSTING OF TURKEY OR CATTLE MANURE

In the last years, there is increasing interest in controlling the pollutant emissions of farm techniques. Composting belongs to the recycling techniques for agricultural wastes. Aeration is one of the most impor-tant factors because composting is basically an aerobic transformation of organic matter. The aim of this study was to determine the effect of aeration on nitrogenous emissions during the composting of turkey and cattle manure as generated by farm-scale management practices: moisture increase, compaction and turning. Around one ton of cattle manure and three tons of turkey manure were composted in six cells for 46 days. The cattle manure was turned or not turned, the turkey manure was either moistened, compacted or stored. Temperature, mass, moisture, carbon and nitrogen content, porosity, bulk density, heap volume and emission of ammonia and nitrous oxide were monitored. The results show that for similar manure the aeration increase induced higher ammonia and nitrous oxide emissions. In the case of cattle manure, the overall nitrogenous emissions were lower than that of turkey manure despite the turning. It was due to the higher carbon availability and the lower nitrogen avai-lability reflected by the higher C:N ratio. Therefore, the management of aeration should take into account the carbon availability in order to con-trol the nitrogenous emissions when composting organic materials with high nitrogen availability