Zhenbo Zhang ,  Hongyun Kou ,  Jinkai Lv ,  Jincheng Si ,  Xinyu Lv ,  Jingjing Wu ,  Naila Asghar ,  Hongxiang Zhao ,  Zhen Liu ,  Tangyuan Ning

Abstract

 Saline-alkali soils limit crop growth through multiple interacting constraints, and single practices are often insufficient. This study aimed to explore the effects of subsoiling, straw mulching, and a composite microbial inoculant on the root-soil microenvironment and winter wheat productivity. A split-plot field experiment was initiated in 2022 on a saline-alkali soil, combining tillage (rotary tillage, RT; subsoiling, ST), straw management (chopped straw incorporation, S1; straw surface mulching, S2), and microbial inoculant application (no inoculant, M0; Brevibacillus laterosporus and Bacillus amyloliquefaciens, M1). The mechanisms were investigated during 2023–2025. Results showed that subsoiling reduced subsoil bulk density, straw mulching stabilized root-zone water and salt, while the inoculant enhanced urease and alkaline phosphatase activities as well as microbial biomass turnover. The integrated STS2M1 treatment significantly increased rhizosphere microbial biomass nitrogen and phosphorus, alkaline phosphatase activity and urease activities, driving nutrient enrichment; it also increased deep root length density by 57.62%-91.42% and active root absorbing area by 8.63%-14.56%. A partial least squares path model (PLS-PM) revealed that these practices reshaped root morphology and function by optimizing soil physicochemical properties, rhizosphere enzyme activities, and microbial biomass turnover, thereby synergistically improving aboveground nitrogen uptake, phosphorus uptake, and grain yield. Compared with the RTS1M0 control, STS2M1 achieved yields of 7544 and 6935 kg ha⁻¹ in two years, increases of 84.89% and 54.88%, with nitrogen uptake rising by 54.77%-56.35% and phosphorus uptake by 60.29%-68.11%. These findings provide a theoretical basis and an integrated technical strategy for sustainable wheat production in saline-alkali soils.

Paper Linkage:https://doi.org/10.1016/j.still.2026.107434