Effects of biochar on nutrients and the microbial community structure of tobacco-planting soils

The effect of rice straw biochar on soil nutrients was studied using a randomized block experimental design in a tobacco-planting field, and differences in soil bacterial and fungal community structures were studied using high-throughput sequencing technology.The results indicated that the soil pH, CEC, total organic carbon (TOC), inorganic carbon (IC), soil total nitrogen (total N), total potassium (total K), available phosphorus (available P), and available potassium (available K) contents were all increased with the biochar application.TOC and available P contents increased by 38.19% and 22.38%, respectively, in the T2 treatment (4500 kg .ha -1 biochar) compared to those in control (CK).But the soil dissolved organic carbon ( DOC) and available nitrogen (available N) content decreased by 13.07% and 9.89% in T2 treatments compared to the CK, respectively.Soil bacteria composition mainly consisted of Proteobacteria, Actinobacteria, and Acidobacteria, and the Proteobacteria proportion represented >50% of the bacterial community.The Actinobacteria proportion decreased, but Proteobacteria and Acidobacteria proportions increased with increasing biochar amounts.Fungi in tobaccoplanting soils were mainly Ascomycota (>75%), but this proportion decreased as the biochar amount increased.However, Zygomycota and Basidiomycota proportions increased with increasing biochar amounts.Therefore, biochar application could improve the soil nutrient status and affect microbial community structure.Rice straw biochar application promoted fungal community diversity in tobacco-planting soils.