Biochar has been shown to promote the growth of crops under continuous cropping. It has been proposed that biochar could improve soil properties and alter bacterial community structure, which however remains to be validated. This study aims to investigate the effects of tobacco stem-derived biochar on soil properties, bacterial community structure, and the growth of Bletilla striata, a traditional Chinese medicinal herb, under continuous cropping. Tobacco stem-derived biochar was applied at 0.00, 3.00, and 7.50 t·ha⁻¹ to the soil after 8-year continuous cropping of B. striata. Soil pH, nutrient availability, enzyme activity, and the growth of B. striata were investigated after transplanting for 6 months. Further, the bacterial community structure was analyzed within the metagenomic framework through high-throughput DNA sequencing. Soil pH, electrical conductivity, available nitrogen, available phosphorus, and available potassium increased significantly with biochar application (P < 0.05). Besides, the activities of soil phosphatase and sucrase also elevated (P < 0.05). The biochar promoted the growth of B. striata, as indicated by the increased plant height, average leaf width, and the content of chlorophyll (P < 0.05). Metagenomic analysis revealed that biochar treatment increased bacterial richness and promoted phylogenetic clustering in the bacterial community. The application of tobacco stem-derived biochar significantly improved soil properties and altered bacterial community structure, which could be the key mechanism for biochar to promote the growth of B. striata under continuous cropping.

生物炭已显示出在连续种植下促进作物生长。有人提出生物炭可以改善土壤性质并改变细菌群落结构，但是仍有待验证。这项研究旨在调查连续种植条件下，源自烟草茎的生物炭对土壤特性，细菌群落结构以及白let的生长的影响。烟梗衍生的生物炭在0.00，3.00施加，并且7.50吨·公顷^-1至后的8年连作土壤B.纹状体。土壤pH值，养分利用率，酶活性和纹状芽孢杆菌的生长移植6个月后进行调查。此外，通过高通量DNA测序在宏基因组学框架内分析了细菌群落结构。施用生物炭后，土壤pH，电导率，有效氮，有效磷，有效钾显着增加（P  <0.05）。此外，土壤磷酸酶和蔗糖酶的活性也升高（P  <0.05）。生物炭促进了B. striata的生长，这通过增加株高，平均叶宽和叶绿素含量（P <0.05）。元基因组学分析表明，生物炭处理增加了细菌的丰富性，并促进了细菌群落中的系统发生簇。烟梗衍生生物炭的应用显着改善了土壤特性，改变了细菌群落结构，这可能是生物炭促进连作下条状芽孢杆菌生长的关键机制。