Diversity of Cultivable Bacterial Populations Provides Evidence for Tobacco-crop Rotations in Alleviating Continuous Cropping Obstacles

Degradation of soil quality, imbalanced microbial community , and reduced crop yields due to continuous cropping are prevalent issues in tobacco agriculture. Rotation is an effective strategy to alleviate these problems. Therefore, this study used flue-cured tobacco monoculture (CK) as a control and set up three treatments: faba bean (YCCD), barley (YCDM), and garlic (YCDS). Various culture media, including NA, LB, PCA, R2A, and modified Gao’s I media, along with Illumina MiSeq highthroughput sequencing, were employed to investigate the impact of these crop rotation patterns on the soil cultivable bacterial community. The results showed that the Ace, Chao1, and Shannon indices were significantly higher in the YCDM treatment (P<0.05). Crop rotation significantly increased the relative abundance of beneficial bacteria, such as Pandoraea, Sporosarcina, and Serratia, as well as the relative abundance of nitrogen, phosphorus, and sulfur cycling genes. Soil pH, organic matter, total phosphorus, available nitrogen, total potassium, and available potassium content were identified as key factors influencing bacterial community structure. In conclusion, different rotation patterns regulate the bacterial community involved in nitrogen, phosphorus, and sulfur cycling by affecting soil pH and nutrient content. The enrichment of cultivable bacterial communities helps mitigate soil degradation and ultimately enhances crop yields.