Characteristics of methane emission from wetland rice-duck complex ecosystem

The effects of rice-duck complex ecosystem on methane emission were investigated through two experimental approaches of plot and field experiments in subtropical region of China. Compared with conventional rice fields, the rice-duck ecological planting and breeding model significantly decreased the methane emission from paddy fields. Methane emission flux from rice-duck complex ecosystem presented distinct diurnal and seasonal variations. The diurnal variation in methane emission flux was basically consistent with daily temperature change, and methane emission flux reached a peak from 12 noon to 2 p.m. But the seasonal variation patterns of methane emission flux were not completely consistent between early rice and late rice. The peak of methane emission flux for early rice and late rice, respectively, appeared in the young panicle differentiation stage and the full tillering stage. Moreover, the seasonal fluctuation range of methane emission flux from early rice was smaller than that from late rice, and the total amount of methane emission from late rice also significantly higher than that from early rice. These results clearly indicate the possibility of reducing methane emission under wetland rice-duck complex ecosystem.