Soil microbiome dynamics associated with conversion of tropical forests to different rubber based land use management systems

The biogeochemical cycles, carbon sequestration, and climate change all are significantly influenced by tropical rainforests, which is one of the world's most productive ecosystems and hotspots for biodiversity. Plantation crops like Rubber (Hevea brasiliensis) have displaced significant forest cover in the Asia pacific in the last two centuries due to their increasing demand. As a case study, we examined the soils of native forest (NF), rubber monoculture (RP) and three different managements i.e., cover crop (CC), weed crop (WC) and inter crop (IC) to understand the changes in microbial community structure across each practice and to estimate the influence of forest conversion to rubber monoculture on the soil microbiome. Soils were collected using nested sampling pattern and subjected to physiochemical characterization and whole metagenome sequencing. Results revealed that bacteria (60.56 M reads) predominated all land use types, followed by eukaryotes (0.52 M reads) and archaea (0.72 M reads). NF exhibited significantly higher bacterial richness and diversity then other land-use type. Interestingly, total functional diversity as well as genes associated with chemotaxis, flagellar assembly, and secretion systems were significantly higher in other land-use systems as compared to NF. Altogether, the results from this study indicate that the three different land use types used here like CC, IC, and WC has high abundance of functional diversity and biological profile compared to NF and RP. The study suggests that the adoption of aforementioned land-use management practices could play a significant role in fostering sustainable plantations in the tropics.