Characteristics of methane emission and its relations with soil carbon status and management practices under double rice systems

摘要

Three aspects were studied on methane emission in typical early-later rice systems in South China. Results showed that ⅰ) Methane emission flux were one times higher in later rice growth period than in early rice period. For the seasonal variation in both early and later rice growth period, early stages (seedling, tillering , and elongating) emitted higher methane than in later stages (earing and mature stages). And the fluctuation pattern of DOC is not coincide with the methane emission pattern, ⅱ) methane emission flux decrease by 60% for the aerated treatment than flooding treatment at the aeration period. And the aeration could decrease the methane at the later stages,ⅲ) For the treatment which was not received straw return of early rice, methane flux decreased by 8% than that which received straw return in the period of later rice growth. Other measurement results showed that the content of available iron and manganese cations in soils of aerated treatment decreased by 21 % and 3131 % respectively than that in soils of flooded treatment.