Carbon footprint, yield and economic performance assessment of different mulching strategies in a semi-arid spring maize system

Crop productivity maximization while minimizing carbon emissions is of critical importance for achieving sustainable agriculture. Socio-economic and ecological benefits should be taken together under the circumstance of stagnant farming profitability and climatic variability. The effectiveness of various mulching strategies in rain-fed semiarid areas has been confirmed, but scarce the comprehensive evaluations of the conventional and new mulching strategies in terms of yield, economic benefit, and carbon footprint based on life cycle assessment (LCA) have been conducted. Hence, a two-year field experiment was conducted on maize (Zea mays L.) crop to explore the effects of four mulching strategies (PM: plastic-film mulching, SM: maize straw mulching, BM: biodegradable-film mulching, and NM: no mulching) on the yield, net return, greenhouse gas (GHG) emissions, and carbon footprint (CF). The results revealed that PM and BM significantly increased maize yield by 11.3-13.3% and 9.4-10.6%. PM marginally raised the net return by 2.0-2.4% whereas BM slightly reduced it by 4.6-8.8% relative to NM. Unexpectedly, the yield and net return were the lowest under SM, and intensified N2O emissions, GWPdirect, and yield-scaled GWPdirect were observed. When the GHGs using LCA concept and SOC sequestration rate were considered, the lowest net GWP (1804.1-1836.4 kg CO2-eq ha-1) and CF (148.9-119.9kg CO2-eq t-1) were observed in the SM treatment due to the boost of soil organic carbon (SOC) sequestration. Conversely, PM and BM significantly increased the net GWP and CF compared to NM. When the tradeoffs between the high production, high net return and low net GWP were assessed by an integrated evaluation framework, the NM was recommended as an efficient low-carbon agricultural practice in the rain-fed semiarid areas.