Bacterial communities in cropland soils: Taxonomy and functions.

Background and Aims: Understanding microbial compositions and functions in arable soils is crucial for effective agroecosystem management. While many studies have explored this topic, large-scale investigations are lacking, resulting in the absence of consistent and reliable patterns of communities and functions of soil microorganisms. Methods: To address this gap, we performed an integrated analysis of published sequencing data from the soils of three main arable fields: upland, paddy, and paddy-upland rotation. Results: Bacterial diversity (richness, Shannon) was highest in upland soils. Actinobacteria and Planctomycetes were enriched in upland soils, while Proteobacteria, Chloroflexi, and Nitrospirae preferred paddy and paddy-upland rotation soils. Bacteria in upland soils have a greater functional potential to decompose aromatic compounds, as well as for chitinolysis and ureolysis. Methanotrophy, methylotrophy, sulfur-related respiration, and most nitrogen metabolic processes were enriched in paddy fields. Bacteria in upland soils are characterized by increased dormancy potential and a faster response to resource input than those in paddy and paddy-upland rotation soils. Stochastic processes poorly contribute to the bacterial assembly in paddy soils, indicating strong environmental filtering due to anaerobic conditions. The spatial turnover in bacterial community composition was much faster than the functional potential, indicating high functional redundancy, especially in paddy soils. Edaphic factors were the major contributors to bacterial composition, whereas the cropland type influenced the predicted functions. Conclusions: Land use defines microbial composition, functional attributes, and ecological characteristics (e.g., dormancy potential, assembly processes, and functional redundancy). These findings deepen our knowledge of microbial biogeographic patterns in soils of agricultural ecosystems and provide new insights into sustainable cropland management. [ABSTRACT FROM AUTHOR]