Nitric Acid Rain Decreases Soil Bacterial Diversity and Alters Bacterial Community Structure in Farmland Soils

Abstract

Being regarded as one of the environmental problems endangering biodiversity and ecosystem health, acid rain has attracted wide attention. Here, we studied the effects of nitric acid rain (NAR) on the structure and diversity of microbial communities in agricultural soils by laboratory incubation experiments and greenhouse experiments. Our results indicated that NAR had an inhibitory effect on soil microorganisms, showing a significant reduction in the Chao1 index and Shannon index of soil bacteria. Proteobacteria, Acidobacteriota, Actinobacteriota, and Chloroflexi were the dominant bacterial phyla under NAR stress in this study. NAR significantly reduced the relative abundance of Proteobacteria and Actinobacteria, but significantly increased the relative abundance of Acidobacteriota and Chloroflexi, suggesting that NAR was unfavorable to the survival of Proteobacteria, and Actinobacteria. It is worth noting that the inhibitory or promoting effect of NAR on the dominant bacterial phyla gradually increased with increasing NAR acidity and treatment time. In addition, the study observed that the change in soil pH caused by NAR was the main reason for the change in soil bacterial community structure. In summary, the effects of NAR on soil microorganisms cannot be underestimated from the perspective of sustainable agricultural development.