Resistance of bacterial community in the sugarcane rhizosphere after straw burning

Abstract

Burning reduced Actinobacteriota and Firmicutes but increased Proteobacteria. Rhizosphere networks were denser, but burning reduced their overall connectivity. Burnt straw increased specialist and generalist taxa, especially in the rhizosphere. Straw management significantly influences soil microbial dynamics, shaping biodiversity and resistance in agroecosystems. This study investigated how distinct straw management practices affect bacterial communities and their ecological interactions in bulk soil and the sugarcane rhizosphere. The study was conducted in an Oxisol using a split-plot design with two straw management treatments (burnt and unburnt) and two soil compartments (bulk soil and rhizosphere). Bacterial communities were characterized using 16S rRNA gene sequencing, followed by analyses of diversity, co-occurrence networks, and niche occupancy. The rhizosphere consistently exhibited higher bacterial richness and diversity, regardless of straw management. Burnt straw reduced the relative abundance of Actinobacteriota (∼52%) and Firmicutes (∼53%) but increased Proteobacteria (∼65%) in bulk soil, whereas the rhizosphere bacterial community remained stable. Network analysis revealed higher connectivity and modularity in the rhizosphere, while burnt straw increased negative correlations and reduced microbial complexity in bulk soil. Niche occupancy analysis showed a higher proportion of specialist taxa in the rhizosphere, particularly under burnt straw. Overall, the sugarcane rhizosphere exhibited high microbial resistance to straw burning. These findings highlight the importance of sustainable straw management for preserving soil biodiversity and maintaining ecological stability in tropical cropping systems.

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