Comparison of methane emission characteristics in air-dried and composted cattle manure amended paddy soil during rice cultivation

• We investigated the effect of air-dried and composted manures on CH4 emission in rice field.
• Compost leads to ∼50% mitigation of CH4 emission compared to air-dried manures.
• Labile organic C content was higher in manure-treated soils than in composted manures.
• C fraction in lighter aggregates of manure treated soils was higher than in composted manures.
• C assimilation in light fractions was possibly the driving force for CH4 emission.

Application of organic matter is essential for sustaining the health and productivity of a soil. However, organic amendments produce methane (CH4) emissions from rice (Oryza sativa L.) paddy soils. In this experiment, we evaluated the relative effects of composted and air-dried forms of different manures on CH4 emission from rice paddy soils. Air-dried and composted manures from both Korean cows and dairy cows were applied to evaluate their effects on CH4 emissions in rice paddy soils. Application of organic amendments increased CH4 emissions from soil during rice cultivation. Application of composted manures reduced CH4 emission by up to 50% compared to air-dried manures. The chemical composition of applied cattle manures may also determine the level of CH4 emissions from rice paddy soils. The amount of decomposable organic C, its distribution in lighter soil aggregates and the potential of these soil aggregates to generate labile C compounds in soil were possible influencing factors in the emission of CH4 from organic amended rice paddy soils.