Effect of Plastic Film Mulching on Greenhouse Gas Emissions from Rice-Rapeseed Rotation in Cropland

Abstract

A field experiment was conducted at the Key Field Station for Monitoring of Eco-Environment of Purple Soil of the Ministry of Agriculture of China at the farm of Southwest University in Chongqing. In the study, static chamber and gas chromatography methods were used to study the effects of plastic film mulching treatment on CO2, CH4, and N2O emissions from rice-rapeseed rotation in situ for one year. A control experiment was also conducted without using the film. The CO2, CH4, and N2O emission fluxes of the rotation showed obvious seasonal changes, and the seasonal variation patterns of these three greenhouse gases were similar under the two treatments. The CH4 emission of the rotation under the plastic film mulching treatment was (46.14±13.40) kg·hm-2, or 147.93% (P<0.05), compared with (18.61±2.05) kg·hm-2 for the control. However, the impact of plastic film mulching on CO2 and N2O emissions was not significant. The annual CO2 emissions under the plastic film treatment and the control were (-47.54±2.11) t·hm-2 and (-47.60±2.19) t·hm-2, respectively, and the annual emissions of N2O were (18.94±4.74) kg·hm-2 and (23.14±3.68) kg·hm-2, respectively. The rice-rapeseed rotation in the two experiments showed absorption and sinking of atmospheric greenhouse gases, although the difference was not significant. The global warming potential (GWP) values with the plastic film treatment and the control were -41.16 t·hm-2 and -40.95 t·hm-2, respectively.