Sao Sochan, Praise Susan, Nishiyama Masateru, Ann Vannak, Phung Luc Duc, Watanabe Toru
The United Graduate School of Agricultural Sciences, Iwate University, 18-8, Ueda 3-Chome, Morioka, Iwate, 020-8550, Japan.
Faculty of Hydrology and Water Resources Engineering, Institute of Technology of Cambodia, Russian Federation Blvd, PO Box 86, Phnom Penh, 120404, Cambodia.
Environ Sci Pollut Res Int. 2025 Mar;32(15):9429-9442. doi: 10.1007/s11356-024-35001-2. Epub 2024 Sep 20.
Flooding profoundly impacts soil bacterial communities; however, the underlying mechanisms remain poorly understood. This study investigated how flooding (3, 8, and 16 days) and post-flooding (immediately and 2, 5, and 30 days) durations affect soil physicochemical properties, bacterial communities, and their interactions-crucial factors in floodplain nutrient and carbon cycling. The results showed that bacteria constituted 99.9% of the total microbial composition, while archaea, contributing only 0.1%, had a negligible impact on soil traits. At 2-5 days after flooding (DAF), elevated soil electrical conductivity (EC) and pH enhanced soil bacterial abundance and activity, leading to increased water-extractable dissolved organic carbon (DOC), water-extractable total dissolved nitrogen, and biological production (BIX), accompanied by the degradation of soil organic matter (SOM) and aromatic compounds (SUVA). These changes indicated robust interactions between soil bacterial communities and physicochemical properties affected by flooding events. However, these relationships weakened at 30 DAF, suggesting potential transitions from anaerobic to aerobic conditions in post-flooding soils after 5 DAF. Structural equation modelling indicated that an extended post-flooding duration increased BIX, accompanied by SOM and DOC degradation, providing nutrients and energy to soil microbes and consequently leading to increased bacterial diversity. This study underscores the significant impact of flooding and post-flooding durations on soil bacterial community composition and diversity, mediated by changes in EC, pH, SOM, and DOM, potentially influencing nutrient cycling in floodplains.
洪水对土壤细菌群落有深远影响；然而，其潜在机制仍知之甚少。本研究调查了洪水持续时间（3天、8天和16天）以及洪水后持续时间（立即、2天、5天和30天）如何影响土壤理化性质、细菌群落及其相互作用，这些都是洪泛区养分和碳循环的关键因素。结果表明，细菌占微生物总组成的99.9%，而古菌仅占0.1%，对土壤特性的影响可忽略不计。在洪水后2至5天，土壤电导率（EC）和pH值升高，提高了土壤细菌丰度和活性，导致可水提取的溶解有机碳（DOC）、可水提取的总溶解氮和生物生产（BIX）增加，同时伴随着土壤有机质（SOM）和芳香化合物（SUVA）的降解。这些变化表明土壤细菌群落与受洪水事件影响的理化性质之间存在强烈的相互作用。然而，这些关系在洪水后30天减弱，表明洪水后5天之后的土壤可能从厌氧条件向需氧条件转变。结构方程模型表明，延长洪水后持续时间会增加BIX，同时伴随着SOM和DOC的降解，为土壤微生物提供养分和能量，从而导致细菌多样性增加。本研究强调了洪水和洪水后持续时间对土壤细菌群落组成和多样性的重大影响，这种影响由EC、pH、SOM和DOM的变化介导，可能影响洪泛区的养分循环。
