Gaseous emission and changes in nutrient composition during deep litter composting

Abstract

Composting of deep litter during storage may cause emission losses of ammonia (NH3 ), nitrous oxide (N2O) and methane (CH 4). Emissions of NH3, N2O and CH4 from deep litter compost were measured using a dynamic chamber over a period of 57 days from 2 July to 26 August 1997. High concentrations of N2O inside the compost heap were found initially and after 20 days of composting. Methane concentrations in the heap were high during days 8-15. As a result of NH3 volatilization, 2.2 kg NH3-N t-1 (23% of total N) was lost in the first 5 days. Emissions of N2O amounted to 0.22% of the total N present at the start of the experiment and CH4 emission represented 0.01% of total C. In this experiment no leaching occurred, and thus non-volatile nutrients were conserved during composting. The population of nitrifying bacteria remained low throughout the experiment (around 10 5 cells g-1 dry matter) and the density of denitrifying bacteria stayed high (4.2 × 107 cells g-1 dry matter). © 2002 Taylor & Francis.