Conserving nitrogen during composting

During the course of aerobic composting, much of the initial nitrogen content in feedstocks may be lost. Most of the nitrogen is lost to the atmosphere as ammonia. it is possible to reduce N loss during composting by: 1. using high C:N mixtures that enhance N immobilization, 2. lowering the pH of the compost solution to increase ammonium solubility, thus reducing ammonia volatilization during the thermophilic stage of composting, or 3. lowering the airflow rate through the compost pile. Three carbonaceous amendments were added to separated cow manure (SCM) to increase the C:N ratio, or to lower the pH of the compost solution. The actual availability of nitrogen and the nutrient release potential of the resulting composts were tested by growing cherry tomatoes under organic conditions. The agricultural efficiency of the composts, as tested on cherry tomato production, revealed that nitrogen mineralization rate was the main factor determining plant growth rate.