Embedded biomass into topsoil as a green production mode to ensure soil structure and functions in arid irrigation region

Background and Aims Polyethylene film mulching is common in dryland agriculture but may degrade soil functions and environmental quality over time. This study aimed to assess biomass‑based mulching as a sustainable alternative that maintains crop yield while reducing plastic pollution in arid regions. Methods This two‑year field experiment in an arid irrigated region examined soil physicochemical properties, soil enzyme activities, and maize yield under six mulching treatments: shallow‑incorporated dried maize straw (SM), living clover embedding (CM), biomass beneath plastic film (PM + SM and PM + CM), sole plastic film (PM), and bare land control (CK). Results Compared with CK and PM, SM and PM + SM greatly reduced soil bulk density and pH, and increased macroaggregates proportion and geometric mean diameter. Both treatments also enhanced organic carbon and labile carbon contents by 17.7%-21.1% and 27.7%-31.8% compared with PM. CM and PM + CM were most effective in promoting nitrogen cycling, increasing total, organic, and inorganic nitrogen by 4.19%, 18.18%, and 4.65%, respectively, relative to CK. PM + SM and PM + CM also resulted in higher microbial biomass and urease and β-glucosidase activities than PM alone. Structural equation modeling further confirmed that the embedded biomass mulching enhanced soil functions and crop yields. Conclusions While combining biomass with plastic film can maximize agronomic outcomes, sole biomass mulching offers comparable improvements in soil quality and yield without the environmental risks of plastic film. Biomass embedding thus represents a nature‑based, sustainable strategy to advance agricultural productivity and soil health in arid regions.