Impact of wheat straw incorporation and fertilizer reduction on peanut yield and soil functions

Balancing crop productivity with sustainable soil management is a critical challenge in modern agriculture.

We conducted a three-year randomized complete block field experiment (2022-2024) to evaluate the integrated effects of wheat straw incorporation regimes and fertilizer reduction on the plant-soil-microbe nexus in peanut (Arachis hypogaea L.) production. Six treatments were compared: no straw return (CT), conventional straw incorporation (SI), deep straw incorporation with a decomposition accelerator (SD), deep incorporation with accelerator and a 25% fertilizer reduction (SDR), surface mulching (SM), and SM with a 25% fertilizer reduction (SMR).

Relative to CT, deep straw incorporation (SD and SDR) significantly increased the three-year mean peanut yield by 12-25%. Notably, the SDR regime maintained final yields, plant nutrient uptake, and soil aggregate stability statistically equivalent to the fully fertilized SD treatment (P > 0.05), successfully substituting for a 25% reduction in mineral inputs. Mechanistically, deep straw incorporation actively reshaped the rhizosphere microenvironment. Deep straw incorporation actively reshaped the rhizosphere microenvironment, enriching beneficial functional microbial taxa including Bacillus, Sphingomonas, and Trichoderma, which subsequently elevated the activities of carbon, nitrogen, and phosphorus-cycling extracellular hydrolases and oxidative enzymes by 1.4- to 2.6-fold. This microbially mediated acceleration of nutrient cycling enhanced soil organic carbon, microbial biomass carbon, and available nutrient pools, thereby improving soil nutrient availability and peanut production capacity.

Our findings demonstrate that deep straw incorporation with targeted microbial decomposition accelerators, combined with a 25% reduction in mineral fertilizer, provides a practical, low-input strategy to sustain high peanut yields, optimize root-zone functions, and advance climate-smart agricultural systems.