The invention relates to the technical field of
crop straw treatment and soil improvement, in particular to a
rice straw returning method for improving
soil fertility, which mainly comprises the following steps: crushing rice straws, soaking with a
sodium hydroxide solution, and
drying; then selecting specific strains, mixing and fermenting to prepare a
microbial agent; preparing a composite additive in proportion; within 1-2 days after the rice is harvested, the pretreated
straw, the
microbial agent and the composite additive are applied to the field, deep ploughing is conducted, and
irrigation is conducted; and finally, performing rotary
tillage and
soil preparation after
straw decomposition, and monitoring and adjusting the pH value of the soil when next-stubble crops are planted. According to the method, straw is pretreated,
lignin is destroyed through a
sodium hydroxide solution, the particle size is accurately controlled,
drying is conducted in cooperation, the microbial
decomposition efficiency is improved, straw and soil are fully mixed through accurate ploughing in the field,
decomposition is accelerated into nutrients, the straw can be powerfully decomposed through a
microbial agent, and the soil micro-
ecology is improved; the composite additive supplements various nutrients and enhances the water and
fertilizer retention capability of soil.