Understanding the response of CH4 absorption to film mulching and nitrogen fertilizer is of value for improving management practices. We monitored the CH4 absorption from plastic film-mulched and no-mulched maize fields that received different N application rates (0, 100, 250 kg·hm-2 and 400 kg·hm-2) using the static chamber technique. In addition, the impact factors (soil inorganic nitrogen, soil temperature and moisture, etc.) were estimated. The results showed that the rain-fed maize fields acted as a sink for CH4, and 48%~60% of the annual uptake was during the fallow period. The annual CH4 uptake rate was 0.99, 1.38, 1.3, 1.37, 1.43, 1.77, 1.68, 1.56 CH4-C kg·hm-2 for FM0, FM100, FM250, FM400, BP0, BP100, BP250 and BP400 treatment in 2014—2015, respectively. Both film mulching and N fertilizer did not increase the CH4 uptake. The soil CH4 uptake was positively correlated with 0 cm and 10 cm soil temperature, but negatively correlated with soil WFPS and soil NH4+-N concentration. The CH4 uptake was negatively correlated with soil NO3--N concentration under no-mulched treatments. |