Effect of moisture control in pile-type composting of dairy manure by adding wheat straw on greenhouse gas emission

Composting tests were carried out on six samples to determine the amount of greenhouse gas (GHG) emissions from pile-type composting of dairy manure with different moisture contents. Moisture contents of initial manure varied from 78.8% to 85.5% depending on the proportion of added wheat straw. Six manure samples, each with a volume of about 1.3 m3, were piled and composted in a chamber, and the amounts of gases emitted were measured using an infrared photoacoustic detector. Among the composting samples, manure with lower moisture contents, that is lower bulk densities, gave better composting conditions. N2O and CH4 emissions during the composting process were estimated at 3.4–30.8 g N2O–N/kg N and 3.1–53.7 g CH4/kg OM of the initial materials, respectively. Higher GHG emissions were observed from samples with higher moisture contents.