Comparative analysis of bacterial community compositions in paddy soils collected from a wide area in central and eastern Japan

Several environmental factors such as soil type, fertilization, and some soil chemical properties are known to affect soil bacterial communities; however, the most important driving force of the bacterial community formation in paddy soils has not yet been clarified. In this study, we aimed to investigate the effects of soil type and field management on bacterial communities in paddy soils, taking into account the differences in soil physicochemical properties. We collected soil samples from 51 paddy fields in six prefectures in Japan. The paddy fields were managed under organic regimes (26 fields), natural-farming regimes (12 fields), or conventional regimes (13 fields). The paddy fields were classified into four soil types: andosol, gray lowland soil, gley soil, and gray upland soil. Soil DNA was extracted from the soil samples collected at 2 to 10 weeks after flooded, and high throughput amplicon sequencing analysis was performed using the 16S rRNA gene as the target.