Study on the influence of Amorphophallus muelleri and flue-cured tobacco rotation on the soil microbial community in Southwest China

The continuous cropping of tobacco soil is an obstacle in current flue-cured tobacco production. To explore the effects of the different planting patterns on soil nutrients and microbial community structure, soil samples from the Amorphophallus muelleri continuous cropping (MMT1), A. muelleri  + flue-cured tobacco rotation (MKT2) and flue-cured tobacco continuous cropping (KKT3) systems were collected at the same experimental site. The characteristics and relationships between the soil microbial community and soil nutrients under the different planting patterns were analyzed via Illumina MiSeq high-throughput sequencing. The results showed that the soil organic matter content, hydrolyzable nitrogen content and pH value in the A. muelleri  + flue-cured tobacco rotation treatment were significantly higher than those in the other two treatments. The composition of the soil microbial communities under the different planting patterns was similar at the phylum level, but the relative abundances of Proteobacteria, Mortierellomycota and Basidiomycota in the A. muelleri  + flue-cured tobacco rotation treatment were 0.31, 0.56 and 0.39 times higher than those in A. muelleri continuous cropping and flue-cured tobacco continuous cropping, respectively. The abundance of Ascomycota in the flue-cured tobacco continuous cropping treatment was 0.02 times higher than that in the A. muelleri continuous cropping of A. muelleri  + flue-cured tobacco (P < 0.05). At the genus level, the abundances of Sphingomonas , Arthrobacter , Bacillus and Mortierella in the A. muelleri  + flue-cured tobacco rotation treatment were 0.84, 0.006, 0.36 and 0.07 times higher than those in the A. muelleri continuous cropping, and 0.78, 1.41 and 0.24 times higher than those in the flue-cured tobacco continuous cropping treatment. The dominant bacteria and fungi were significantly correlated with the soil nutrients. From the perspective of microbial function, the bacterial KEGG enrichment pathway of the tested soil samples was mainly the metabolism pathway. The energy metabolism, carbohydrate and amino acid gene abundances of the soil bacterial community after A. muelleri  + flue-cured tobacco rotation were higher than those after A. muelleri continuous cropping and flue-cured tobacco continuous cropping. The rotation planting pattern plays a positive role in regulating soil nutrients, improving the microbial community structure and increasing the functional metabolism of beneficial bacteria. The results of this study can provide a reference for the production of high-quality flue-cured tobacco.