| Abstract:The soil of continuous cropping of protected pepper（ Capsicum annuum） in Jianzha county of Qinghai province was used as the object to study the change characteristics of soil enzyme activities and microbial community structures in different years of continuous cropping,which is expetected to explore the relationship between microbial communities and soil physicochemical properties. The results showed that the activities of saccharase,alkaline phosphatase and catalase in the continuous cropping soil of protected peppers decreased significantly with the increase of continuous cropping years,while the activities of urease,acid protease,acid invertase and cellulase increased first and then decreased. Besides,the activity of polyphenol oxidase decreased first and then increased. Continuous cropping changed the microorganisms in protected pepper soil from the “bacterial type” to the “fungal type”. As the years of continuous cropping increased,the abundances of dominant phylums such as Proteobacteria and Bacteroidetes and beneficial genera such as Desulfovibrio and Sphingomonas were relatively reduced. Compared with the control,in the fifth year of continuous cropping,these categories decreased by 19.70%,41.32%,37.40% and 50.37%,respectively.Soil fungal diversity increased with the increase of continuous cropping years. Compared with the control,in the fifth year of continuous cropping,the relative abundances of dominant Ascomycota and Fusarium increased by 27.19% and 82.65%,respectively.The correlation analysis showed that soil physicochemical properties such as electrical conductivity,volumic mass,total phosphorus and pH were significantly correlated with microbial communities (P<0.01). The relative analysis showed that continuous cropping of protected pepper resulted in changes in soil enzyme activities and deterioration of microbial environment. The results of this study can provide a reference for the formation and effective control of the continuous cropping obstacles of protected pepper. |
