The pattern of methane emission in wetland rice-duck complex ecosystems was studied in block experiment and field production. The results showed that methane emission displayed clear seasonal variation in rice-duck complex ecosystems. In the case of the early rice-late rice cropping system,methane emission peaked in the first part of June and the end of July respectively.Methane emission also varied by the growth course,For early rice, 2 methane emission peak of 13^693mg/(m 2·h) appeared in the young panicle differentiation stage, and for late...