Emissions Caused by Manure Composting

Abstract

The evaluation of the nitrogen balance of biological farming included the measurement of gaseous emissions during manure composting under practical conditions. The results show that ammonia- and methane emis- sions subside within three to four weeks. Nitrous oxide emissions exhi- bited significantly greater variability with regard to time and place. Ma- xima of nitrous oxide emission were observed mainly after ammonia and methane had decayed. The mean total flux per compost period amounted to 1,322 g m-2 of methane, 76.9 g m-2 of ammonia, and 19.8 g m-2 of ni- trous oxide. The relation of these average values to the mean flux of car- bon dioxide per composting period was 4.6 10-2 for CH4 , 2.7 10-3 for NH3 , and 6.9 10-4 for N 2 O. Both the total average gas flux and the mean ratio of total gas emissions can serve to quantify the impact on the envi- ronment. The average gaseous nitrogen losses measured during manure composting amounted to 6% of the initial nitrogen content. Carbon los- ses account for 35% of the initial carbon content.