Effect of different continuous cropping years on the rhizosphere soil microbial community structure of Tussilago farfara L.

Abstract The rhizosphere soils from 1, 2, and 3 years of Tussilago farfara L. continuous cropping were used as the research objects. The region of bacterial 16S rRNA and fungal ITS was analyzed by Illumina MiSeq high-throughput sequencing technology. The effect of continuous cropping years on the microbial community structure and diversity in Tussilago farfara L. soil was investigated. The result shows that rhizosphere soil fast-acting nutrient content, alkaline phosphatase, and sucrase activity gradually decreased, urease activity increased first and then decreased, and catalase activity did not change significantly with the increase of cropping years. The number and diversity of rhizosphere soil bacteria increased first and then decreased, while the fungal species increased by 22.5% after continuous cropping for two years compared with rotational cropping. Among the bacteria, the relative abundance of Proteobacteria and Acidobacteria decreased significantly after continuous cropping, and the relative abundance of Actinobacteria and Chloroflexi increased; among the fungi, the relative abundance of Ascomycota and Basidiomycota decreased significantly after continuous cropping, while the relative abundance of Mortierellomycota increased. The population type gradually changed from bacterial to fungal, and the relative abundance of beneficial genera such as Ralstonia, Nitrospira, and Trichoderma gradually decreased, while harmful genera such as Mortierella, Fusarium, and Tricharina accumulated in large quantities. This study reflects the dynamic balance of rhizosphere soil bacterial-fungal communities of Tussilago farfara L. in different continuous cropping years, and the changes of nutrient content, enzyme activity, and genera reflect the possible genera associated with the occurrence of cropping obstacles of Tussilago farfara L., as well as the relevant groups of bacteria to maintain the stability of microbial communities, which provides a scientific reference basis for further investigation of cropping obstacles and screening of beneficial genera.