Deciphering Characteristics of Bacterial Diversity and Potential Function in Acidic Soils of Jiaodong Peninsula, China

ABSTRACT Soil acidification globally stressed agricultural production and food security. Jiaodong Peninsula, an important agricultural area of China, is also experiencing a serious soil acidity problem. However, There is limited knowledge regarding the differences of microbial diversity and functions in acidic soils in relation to land uses. Here, bacterial diversity and functions were compared between orchard and farmland soils of the Jiaodong region, in addition to soil progressive acidification. The results demonstrated that compared to farmland soils (pH is 5.36 average), orchard soils with an average pH of 4.70 faced a more serious acidic problem, which were characterized by lower nitrogen availability and a higher total phosphorus content. Yet, no significant differences were found in bacterial community diversity and taxa composition between the two landuse soils. While, the specific predominant taxa, such as Proteobacteria, Actinobacteriota, Acidobacteriota, were more abundant in orchard soils than in farmland soils. Similarly, for most network parameters (such as node, edge, modularity), the higher values were gotten in orchard soils than farmland soils. By contrast, the progressive acidification of soil had a more significant impact on the structure and diversity of the bacterial community. The further statistical analysis indicated that except of soil pH, soil total phosphorus and nitrogen availability were also top factors shaping the bacterial communities' interaction. Based on predicted functional profiles, the function gene related to amino acid metabolism was higher enrichment in farmland soils than orchard soils, which was similar to most different functional categories between both soils except of amino acid transport and metabolism. Our results suggest that compared to soil pH controlling bacterial community structure and diversity, agricultural practices related to land use might regulate microbial activities involved in nutrients cycle in acidic soils of Jiaodong Peninsula.