Exploration of Microbial Diversity of Anoxic Soil Under Submerged Low-Land Paddy Cultivation by Culture-Independent Methods for Its Consequent Ramifications on Environment, Soil Health, and Sustainability

Abstract

Soil microbes, the primary components of soil biodiversity, provide crucial ecosystem services. Anthropogenic activities, such as agriculture, bring about innumerable biotic and abiotic changes in the soil ecosystem that can have short and long-term impacts on the environment and soil sustainability. Lowland paddy cultivation is a typical example of anthropogenic disturbance to soil, where the paddy field fluctuates between waterlogged conditions and extreme dry spells, which have some immediate effects, such as greenhouse gas emissions, and a probable long-term impact on soil, altering soil oxidoreduction states and influencing microbe-driven nutrient and carbon cycling. Although rice is a dominant crop in Northeast India, microbial responses to paddy cultivation remain poorly documented. In this study, we compared the soil microbiomes of paddy fields and adjacent non-paddy land in the Bhagawatipara region of Kamrup district of Assam, India, using 16S rRNA amplicon sequencing. Paddy soils exhibited clear shifts in microbial abundance, with an increased representation of methanogens, nitrogen-transforming archaea, diazotrophs, and phosphatesolubilizing bacteria. Distinct changes in alpha and beta diversity further indicated strong hydrological and cultivation-driven impacts on microbial community dynamics. This study provides the first comprehensive microbial dataset for paddy soils in the Kamrup district (Assam) and highlights key microbial signatures associated with methane cycling and soil nutrient processes.