Investigating the effects of various irrigation methods on bacterial communities in paddy soil

Different irrigation methods can impact the micro-ecological environment of paddy soil, affecting crop growth. This study focuses on County A, a key grain production area on China’s East Coast, where 20 plots each of intermittent and flood irrigation were selected and labeled as Group I and Group F, respectively. Soil's basic physicochemical properties and heavy metal content were measured in the laboratory, and high-throughput sequencing was used to analyze soil bacterial communities. The study evaluated the impact mechanisms of different irrigation methods on these bacterial communities. Results indicate: (1) Intermittent irrigation significantly increased bacterial richness, evenness, and diversity, enhancing microbial community diversity and stability. (2) Intermittent irrigation notably raised the abundance of 9 bacterial genera (e.g., Nitrospira, H16) while reducing the abundance of 7 genera (e.g., Geobacter, Sphingomonas). (3) The soil environment in Group I was stable, with bacterial communities influenced by SMC, pH, and Cu; Group F was affected by multiple environmental factors. Intermittent irrigation provides a stable environment that supports bacterial diversity and abundance, contributing to a richer community structure. (4) Intermittent irrigation optimizes moisture, significantly enhancing bacterial functions such as energy production, cell wall biosynthesis, repair, and signal transduction. These findings suggest that intermittent irrigation improves bacterial community stability and diversity, which is crucial for enhancing the overall quality of paddy fields.