Effects of biological organic fertilizer on rhisosphere soil bacteria community and root rot diseases of continuous cropping Angelica sinensis

Abstract

Understanding the effects of biological organic fertilizer DZF-363 on the growth, root rot diseases, and the structure and function of soil microbial community of Angelica sinensis could provide theoretical basis for the adjustment and improvement of soil environment in the rhizosphere of continuous cropping. Taking 2-year continuous cropping A. sinensis and its rhizosphere soil as test objects, with control (without any pesticides, micro-fertilizer, CK), pesticides groups (15% chlorpyrifos and 50% carbendazim, N), and DZF-363 (DZF) treatments, microbial community structure, and urease and phosphatase activities in rhizosphere soil were figured out by high throughput sequencing and colorimetric method. The results showed that the yield of DZF-363 group was 18.8% higher than CK and 6.8% higher than N. The root rot disease index in the DZF was reduced, with a control effectiveness of 52.0%. The activities of urease, neutral phosphatase and alkaline phosphatase in rhizosphere soil were significantly increased during the growing season, and the urease acti-vity increased by 52.4%, 13.9%, 10.3%, neutral phosphatase activity by 15.5%, 10.2%, 10.3%, alkaline phosphatase activity by 10.3%, 4.4%, 4.0% compared with CK during seedling and middle, and harvesting stages, respectively. The acid phosphatase activity increased by 15.6% and 8.2% at middle and harvesting stages, respectively. The proportion of Actinobacteria in CK, N and DZF groups was 11.3%, 10% and 20%, respectively. The proportion of unidentified Bacillibacteria and Actinobacteria was larger in DZF than in the CK and N groups. The Shannon index was significantly increased by DZF. There was positive correlation between Shannon and Simpson indices with the yield of A. sinensis, while negative correlation with the root rot disease. Therefore, the application of DZF-363 could strongly improve the diversity of soil bacteria in the rhizosphere, alter the soil bacterial community structure and rhizosphere soil urease and phosphatase activities, reduce the occurrence of root rot diseases, and thus increase the yield.