Study on the effect catalytic rotting and returning of rice straw to the field on rhizosphere soil and rice yield

In-situ straw return is an effective agronomic practice for improving soil quality and increasing crop yields. However, in Northeast China, prolonged seasonal freezing lasting more than 6 months markedly restricts straw decomposition, thereby limiting the benefits of straw return in saline-alkali soils. To overcome this constraint, cold-tolerant bacterial agents were applied to promote the decomposition and in-situ return of rice straw under frozen and low-temperature conditions. The results demonstrated that under freezing and low-temperature conditions, the application of the microbial agent (CF) increased the rice straw decomposition rate to 51.22%, which was significantly higher than that observed in the control treatment (34.64%). The germination index of seeds exposed to the decomposed straw reached 102.87%, indicating that the decomposition products met safety standards. CF treatment reduced rhizosphere soil pH and salinity, while significantly increasing the diversity and abundance of rhizosphere microorganisms. In particular, it promoted the enrichment of bacterial genera associated with nitrogen fixation and straw decomposition. At the same time, CF application enhanced rhizosphere soil nutrient levels, which in turn significantly improved rice growth parameters, including tiller number, plant height, and dry weight. Consequently, rice yield increased by 5.84% compared with the control treatment. In summary, the application of cold-tolerant bacterial agents enables efficient in-situ decomposition and return of rice straw under freezing and low-temperature conditions. This approach effectively enhances rice productivity in saline-alkali farmland and provides a simple, practical, and scalable strategy for overcoming straw decomposition limitations in cold regions worldwide.