The field mulching could improve sustainability of spring maize production on the Loess Plateau

Despite field mulching has been widely adopted to improve crop productivity, agro-ecosystem sustainability of this technology in arid and semi-arid areas is inconclusive. We examined the response of yield stability, changes in soil water storage (ΔSWS), nitrogen (N) budget, soil total nitrogen (TN) content and soil organic carbon (SOC) content to furrow-ridge tillage and film or straw field mulching practices in a 6-year field experiment of rain-fed spring maize (Zea mays L.) on the Loess Plateau from 2016 to 2021. Five tillage practices included conventional tillage (CT), ridge tillage (RT), flat planting with plastic film mulching (FM), ridge tillage with plastic film mulching on ridge (RTF) and maize straw mulching (SM). Nitrogen application rates were 0 and 225 kg N ha−1. Maize yield and yield sustainability index (SYI) of plastic film mulching increased by 26.8%− 73.4% and 4.4%− 13.9%, respectively, compared with CT, and coefficient of variation (CV) of plastic film mulching declined by 0.7%− 10.7% relative to that of CT. The average ΔSWS of all tillage patterns were positive, and the rainwater use potential was 88.3–96.9%. The N budget in all practices was positive under N applied treatments but negative without N input. Without N application, N consumption was substantially exacerbated by plastic film mulching, whereas it was mitigated to some extent by SM. The TN and SOC contents were maintained under plastic film mulching. Soil TN and SOC contents in SM increased by 27.1–29.8% and 22.3–33.3%, respectively, in tested stage. However, its yield varied substantially, particularly under no N application. Small yield increase and higher CV and lower SYI occurred in RT practice. The SOC declined similar to CT. Overall, there was higher variation of yield in SM practice. The SOC appeared to decline in RT practice. The plastic film mulching was a promising practice to increase and stabilize maize yields, improve the rainfall use potential, increase or maintain the TN and SOC contents in semi-arid regions. However, attention should be paid to the impact of microplastic contamination in future research.