Anaerobic Soil Disinfestation Promotes Soil Microbial Stability and Antagonistic Bacteria Abundance in Greenhouse Vegetable Production Systems

Abstract

Excessive water and fertiliser inputs, as well as long-term monocropping, not only cause resource waste and environmental pollution but also drive soil degradation and the occurrence of soil-borne diseases. Anaerobic soil disinfestation (ASD) is a widely used technique in greenhouse vegetable production to replace the use of agrochemicals in disinfestation and improve product quality. While the short-term effects of ASD on the soil microbial community have been well documented in the past 15 years, only a few studies have investigated the multiseason effects of ASD, particularly on the soil microbial community composition and stability, as well as on pathogens and antagonistic microorganisms. Field experiments were conducted in three adjacent greenhouses used for tomato production for at least 20 years. Three treatments were included: CK (control: no irrigation, no plastic film covering, incorporation of chicken manure), ASD (irrigation, plastic film covering, and incorporation of rice husks), and ASD+M (ASD plus incorporation of chicken manure). Results showed that (1) ASD significantly reduced the diversity of soil bacteria and fungi and improved the complexity and stability of the soil bacterial community at the end of the ASD, but the soil microbial diversity recovered to the level before the experiment after 1.5 years. (2) Compared with CK, ASD significantly increased the relative abundance of antagonistic bacteria Bacillus, Paenibacillus and Streptomyces, decreased the relative abundance of pathogens Fusarium and the quantity of nematodes and could still effectively eliminate soil pathogens after 1.5 years. (3) Chicken manure application did not increase the pathogenic microorganisms Fusarium and nematodes, but it significantly decreased the relative abundance of antagonistic bacteria. Our results highlight that ASD not only showed an inhibitory effect on soil-borne diseases after 1.5 years but also significantly increased the relative abundance of antagonistic bacteria. However, the additional incorporation of chicken manure for ASD should be avoided due to its negative effects on the abundance of antagonistic bacteria and its contribution to environmental pollution due to N leaching and increased emissions of GHG N2O.