During manure storage, methane (CH4) is produced by anaerobic decomposition of organic matter by methanogens. Frequent removal and further processing of manure from the barn can reduce CH4 emissions. However, little is known about how much CH4 is lost during the adaptation of methanogens to the changing environment from the gut to storage. The objective was to determine the breakdown of organic matter and emission of CH4 from dairy cattle and pig slurry in the first 3 days after excretion. CH4 and carbon dioxide (CO2) emissions from fresh slurry (<1 h old) were measured in climate respiration chambers. Three treatments were studied: (1) dairy cattle slurry with a temperature of 15°C (CS15), (2) dairy cattle slurry with a temperature of 20°C (CS20) and (3) pig slurry with a temperature of 20°C (PS20). CH4 emissions from both dairy cattle and pig slurry were minimal during the first 3 days after excretion. Temperature influenced emission rates, resulting in higher CH4 and CO2 emissions from CS20 than from CS15. Cumulative CH4 and CO2 emissions from PS20 were not significantly different from those of CS20, but emission patterns of pig slurry differed from cattle slurry. Less than 0.3% of the methane potential and only about 0.7% of the IPCC Tier 1 emission factor were emitted as CH4 during the first 3 days after excretion. In conclusion, quick removal of manure from the barn can reduce emissions, although immediate removal is not required from a CH4 emissions perspective.
Boxmeer et al. (Thu,) studied this question.