Reductive soil disinfestation (RSD) is an effective practice to eliminate plant pathogens and improve the soil microbial community. However, little is known about how RSD treatment affects microbial interactions and functions. Previous study has shown that RSD-regulated microbiomes may degenerate after re-planting with former crops, while the effect of planting with different crops is still unclear. Here, the effects of both RSD treatment and succession planting with different crops on microbial community composition, interactions, and functions were investigated. Results showed that RSD treatment improves the soil microbial community, decreases the relative abundance of plant pathogens, and effectively enhances microbial interactions and functions. The microbial network associated with RSD treatment was more complex and connected. The functions of hydrocarbon (C, H), nitrogen (N), and sulfur (S) cycling were significantly increased in RSD-treated soil, while the functions of bacterial and fungal plant pathogens were decreased. Furthermore, the bacterial and fungal communities present in the RSD-treated soil, and soil succession planted with different crops, were found to be significantly different compared to untreated soil. In summary, we report that RSD treatment can improve soil quality by regulating the interactions of microbial communities and multifunctionality.

Red paddy soil is widely distributed in the south of China and has become an important production system for food and cash crops. However, the key factors limiting the quality of this soil type under the plastic shed cultivation system and the effective management strategies are still unclear. In the present study, the physicochemical and microbial properties of red paddy soil in a plastic shed (PS-Soil) and open-air (OA-Soil) cultivation systems were compared. Subsequently, reductive soil disinfestation (RSD) and organic fertilizer treatment (OF) were used to improve the soil properties in a representative PS-Soil. Results showed that the physicochemical and microbial properties in PS-Soil were significantly altered compared with those in the nearby OA-Soil, and those differences were primarily dominated by the cultivation system rather than the sampling site. Specifically, the electrical conductivity (EC) and available nutrients (NO₃⁻-N, NH₄⁺-N, available K, and available P) contents, as well as the abundances of fungi, potential fungal soil-borne pathogens (F. oxysporum and F. solani), and fungi/bacteria were significantly increased in PS-Soil. In addition, the OF treatment could not effectively improve the above-mentioned soil properties, which was mainly reflected by that soil EC and the abundances of potential fungal soil-borne pathogens were considerably increased in the OF-treated soil. In contrast, soil EC and NO₃⁻-N content, the abundances of fungi, F. oxysporum, F. solani, and fungi/bacteria were remarkably decreased by 76%, 99%, 98%, 92%, 73%, and 85%, respectively. Moreover, soil pH, the abundance of bacteria, total microbial activity, metabolic activity, and carbon source utilization were significantly increased in the RSD-treated soil. Collectively, red paddy soil is significantly degraded under the plastic shed cultivation system, and RSD rather than OF can effectively improve the quality of this soil type.