Plastic film mulching mitigates the straw-induced soil greenhouse gas emissions in summer maize field

Abstract The positive impact of straw incorporation (S1) on mitigating global warming potential due to increase soil organic carbon sequestration can be offset by the straw-induced greenhouse gas (GHG) emissions. Therefore, this study advocated an optimal straw-based system, i.e. straw incorporation plus half plastic film mulch (SP), to mitigate the straw-induced GHG emissions in northwest China. A two-year field experiment was conducted to investigate effects of no straw inputs (S0), S1 and SP on yields, GHG emissions and soil labile carbon (C) and nitrogen (N) pools, and identify the relationship between GHG emissions and soil labile C and N pools. Results showed that SP significantly enhanced maize yield by 14.5 and 7.0% in 2018 and 2019, respectively, as compared to S0, mainly due to the increased soil inorganic nitrogen (SIN) and dissolved organic nitrogen (DON) contents. In addition, SP considerably mitigated the straw-induced CO2 emission by 77.8 and 67.1% in 2018 and 2019, respectively, mainly attributed to the reduced dissolved organic carbon (DOC)/DON, microbial biomass carbon (MBC)/SIN and DOC/SIN. Moreover, SP significantly lessened the straw-induced N2O emission by 43.6 and 59.5% in 2018 and 2019, respectively, due to significant decreased DOC content during seeding to jointing, the major N2O emission period. Our results indicated that SP, as a kind of straw-based system, enhanced the sustainability of summer maize ecosystem because of mitigating the straw-induced GHG emissions and simultaneously enhancing maize yield.