To realize the comprehensive utilization of resources of moutai-flavor vinasse and improve the nitrogen efficiency of yellow soil, a field culture experiment was carried out to study the effects of short-term application of vinasse biochar on nitrogen availability and bacterial community structure diversity in yellow soil of Guizhou by setting 5 biochar dosages of 0% (MB0), 0.5% (MB0.5), 1.0% (MB1.0), 2.0% (MB2.0), and 4.0% (MB4.0). The results showed that the total nitrogen(TN) and nitrate nitrogen(NN) content in the soil increased by 35.79%-365.26% and 122.96%-171.80%, the microbial biomass nitrogen (MBN) content decreased by 34.10%-59.95%, and the AN/TN, NN/TN, and MBN/TN exhibited a decreasing trend with an increase in the amount of biochar applied. The application of vinasse biochar significantly reduced the number of OTU and community richness and diversity of soil bacteria; the influence degree increased with an increase in the application amount of vinasse biochar. In comparison with the MB0 treatment, the application of biochar significantly changed the soil bacterial community structure. The relative abundance of Bacteroidetes increased by 1.76-2.11 times with an increase in the biochar application. However, the relative abundance of Acidobacteria, Chloroflexi, Gemmatimonadetes, Planctomycetes, Armatimonadetes, Thaumarchaeota, and Nitrospirae decreased to different degrees, with the most significant decrease in the MB4.0 treatment. The application of vinasse biochar increased the relative abundance of certain soil functional bacteria, such as Streptomyces and Pusillimonas, and simultaneously also decreased the relative abundance of the dominant bacteria, such as Lysobacter and Gemmatimonas. In addition, the redundancy analysis (RDA) showed that the MBN/TN, NN, and MBN were the main cause of soil bacterial community structure change in nitrogen environment factor. The MBN/TN and MBN exhibited a significantly positive correlation with Thaumarchaeota and Nitrospira, which indicated that the short-term application of vinasse biochar can significantly reduce the abundance of ammonia-oxidizing archaea and nitrifying bacteria, inhibit the ammonia-oxidizing effect and nitrification rate of soil, and improve the availability of soil nitrogen. In summary, the short-term application of vinasse biochar can improve nitrogen nutrients, change the structure and diversity of soil bacterial community, and effectively control the risk of soil nitrogen leaching by inhibiting ammonia oxidation and nitrification of soil, to improve the availability of soil nitrogen.
Keywords: bacterial community structure; diversity of bacterial community; moutai-flavor vinasse biochar; soil nitrogen; yellow soil.