Changes in microbial community and enzyme activity in soil under continuous pepper cropping in response to Trichoderma hamatum MHT1134 application

To clarify the control effects of Trichoderma hamatum strain MHT1134 on Fusarium wilt in continuous pepper cropping fields and its regulatory effects on soil microecology, the physical and chemical properties, enzyme activities, community structures of soil samples from five field types were analysed. Samples were taken from fields that had been continuously planted for 1, 5, 9 years, and applied the strain MHT1134 for 1 and 2 years. The MHT1134 control effects on pepper wilt after application 1 year and 2 years were 63.03% and 70.21%, respectively. 4 kinds of physical and chemical indexes and 6 kinds of enzyme activities in soil were increased. With the continuous cropping years increased, the microbial abundance and diversity decreasing significantly. The relative abundances of Fusarium, Gibberella increased along with the planting years, but decreased after the MHT11134 application. However, the relative abundances of Trichoderma and Chaetomium significantly increased. Additionally, as the cropping years increased, the soil abundance of Actinobacteria gradually decreased, but it significantly increased from 17.56 to 22.44% after the MHT1134 application. Thus, strain MHT1134 effectively improved the microbial community structure of the soil, and it also positively affected soil quality. A continuous application may improve the control effect.