[Impact of Distiller's Grain Ash on the Bacterial Community Structure of Acidic Purple Soil].

Abstract

Distillers' grains ash and biochar play a crucial role as ameliorants for improving the quality of acidic soils. To evaluate the impact of distillers' grains ash on the bacterial community structure in acidic purple soil, a field experiment was conducted with six treatments as follows： no fertilizer （CK）, chemical fertilizer alone （F）, lime + chemical fertilizer （LF）, organic fertilizer + chemical fertilizer （OF）, biochar + chemical fertilizer （BF）, and distillers' grains ash + chemical fertilizer （JF）. Illumina MiSeq high-throughput sequencing technology was employed to analyze the effects of different treatments on the physicochemical properties, bacterial community diversity, community structure, and functional groups of the acidic purple soil. The results showed that, compared to the CK treatment, all ameliorant treatments significantly increased the pH, available nutrients, organic matter, and soluble carbon content of the acidic purple soil （P < 0.05）. The effects of different treatments on the bacterial richness index （Chao1 index） of acidic purple soil were as follows： JF>OF>CK>F>BF>LF, while the bacterial diversity index （Shannon index） was： OF>CK>F>JF>BF>LF. Principal component analysis （PCA） and β-diversity analysis indicated that different ameliorant treatments significantly altered the bacterial community structure of acidic purple soil （P = 0.001）. Compared to CK, the ameliorant treatments effectively increased the number of specific ASVs in the soil bacteria, with the JF treatment showing the most significant increase of 50.7%. The dominant bacterial phyla in all treatments were Actinobacteria, Proteobacteria, and Firmicutes, with the JF treatment effectively enriching functional bacterial groups beneficial for soil health and promoting crop growth, such as Paeniglutamicibacter and Rhodococcus. Mantel test, correlation heatmap, and redundancy analyses showed that soil organic matter, pH, and total organic carbon were the main environmental factors influencing the bacterial community structure, with soil pH having the most significant positive impact on bacterial community diversity. Overall, different soil ameliorants had varying mechanisms and effects on bacterial communities. The application of distiller's grains ash and biochar demonstrated superior effectiveness in improving the physicochemical properties of acidic purple soil and enhancing microbial activity, particularly increasing the abundance of Actinobacteria, making them excellent ameliorants for acidic soils.