Long-term straw incorporation regulates greenhouse gas emissions from biodegradable film farmland, improves ecosystem carbon budget and sustainable maize productivity

Context or problem: There is an urgent need to improve traditional film-mulched cultivation to minimize greenhouse gas emissions and increase crop yields simultaneously.Objective or research question: Mulching biodegradable films and straw returning are recognized as potential methods to achieve the above goal. However, the comprehensive study of the long-term application of biode-gradable film combined with straw incorporation on maize yield, system carbon balance and applicability in future climate conditions is very limited. Methods: Therefore, a 6-years two-factor positioning experiment was set up in a typical semi-arid area of the Loess Plateau (2015-2021). Factor one is different film mulching cultivation measures, including double ridge-furrow (D) and fiat planting (F), and factor two is straw incorporation (S) or not (NS), forming four treatments (DS, FS, D and F). Comparing the difference of water use efficiency (WUE), temperature uses efficiency (TUE), carbon emission (Rh and CH4), nitrogen emission (N2O), and maize yield among different treatments.Results: The results showed that straw incorporation enhanced the capture and utilization of precipitation and solar energy of different film-mulching cultivation methods under different climate types and increased maize grain yield by 5.97 % on average. Although straw incorporation increased the cumulative emission of Rh and N2O by 19.76 % and 37.87 %, it significantly improved the net ecosystem carbon budget (NECB). It stabilized the carbon footprint (CF) per unit grain yield between -0.005 and -0.5 kg eq-CO2 kg-1. These commercialized environmental benefits further increased net income (NI) by 326.31 yen ha-1. Compared with FS, the average WUE and TUE, cumulative net ecosystem carbon budget (NECB) and NI of DS from 2019 to 2021 were 5.31 %, 9.05 %, 1.53-fold and 4.89 % higher, respectively.Conclusions: Long-term straw incorporation improved the use efficiency of the natural resource of spring maize, kept the annual grain yield at a high level, and adjusted the carbon budget, making the ecosystem a net sink of GHG emissions. The results refiected higher economic benefits (direct and commercial environmental benefits). In the long-term monitoring, DS showed better stability and superiority than FS in the above aspects. Implications or significance: Double-ridge furrow sowing with full biodegradable film mulching combined with straw incorporation provides a new film mulching strategy for agricultural production and carbon management in semi-arid rain-fed areas and similar agroecosystems.

Automated summary

Long-term straw incorporation improves the use efficiency of natural resources for spring maize, maintains high annual grain yield, and adjusts the carbon budget, making the ecosystem a net sink of greenhouse gas emissions. Double-ridge furrow sowing with full biodegradable film mulching combined with straw incorporation provides a new film mulching strategy for agricultural production and carbon management in semi-arid rain-fed areas and similar agroecosystems.