Conclusions
This study showed that the maize straw substituted for chemical fertilizers significantly improved double-cropping rice yield by promoting soil quality, including soil physical properties, soil enzyme activities, microbial biomass, and soil nutrients, especially in HS treatment. The yield of double-cropping rice was highly significantly correlated with soil bulk density, total porosity, catalase, MBC, MBN, and AP, and was significantly correlated with SAC and ACP, whereas there was no significant correlation with TK. In summary, straw substituted for chemical fertilizers is a high-yield, resource-saving and soil improvement operation mode.