Nitrous oxide and carbon dioxide emissions from soils amended with compost and manure from cattle fed diets containing wheat dried distillers' grains with solubles

The N2O and CO2 emissions from soil amended with cattle manure and compost from animals fed a diet including wheat dried distillers' grains with solubles (DDGS) were evaluated in a 105 d aerobic incubation study in the laboratory. Manure (BM) and compost (BC) from cattle fed a typical finishing diet containing barley, and manure (DDGSM) and compost (DDGSC) from cattle fed a diet containing 60% wheat DDGS replacing barley grain, were used. A nonamended control (soil without manure or compost) was included for comparison. Organic amendments significantly increased N2O and CO2 emissions compared with the control, and manure resulted in significantly higher CO2 emissions than compost. Adding DDGS to cattle diet resulted in significantly higher N2O emission amounts and emission factors from soil regardless of whether the amendment was manure or compost, mainly due to increased NH4+-N content. While N2O emissions were lower in soil amended with DDGSC than DDGSM, there was no difference in N2O emissions when soils were amended with BM and BC. Our results suggest that across diet types and management approaches, application of compost from cattle fed a typical diet could be less detrimental to the environment with relatively lower emissions of CO2 and N2O.