Amazon forest-to-agriculture conversion alters rhizosphere microbiome composition while functions are kept

Area of Science:

• Soil microbiology
• Ecology
• Agricultural science

Background:

• Conversion of native forests to agriculture is a primary driver of microbial biodiversity loss in Amazonian soils.
• Understanding these shifts is crucial for sustainable land management and soil health.

Purpose of the Study:

• To investigate microbial community patterns and functions in bulk soil and soybean rhizosphere during long-term forest-to-agriculture conversion using metagenomics.
• To identify the impact of agricultural practices on soil microbial diversity and functional potential.

Main Methods:

• Metagenomic analysis of bulk soil and soybean rhizosphere microbial communities.
• Long-term study of forest-to-agriculture conversion sites.
• Analysis of soil chemical properties influenced by liming and fertilization.

Main Results:

• Long-term agricultural conversion resulted in microbial homogenization and reduced diversity in both bulk soil and rhizosphere.
• Key bacterial phyla (Acidobacteria, Actinobacteria, Proteobacteria) decreased, while alpha- and beta-Proteobacteria were enriched in the rhizosphere.
• Functional shifts were prominent in bulk soil, with decreased potassium metabolism and increased nucleic acid metabolism, while the rhizosphere showed functional stability except for potassium metabolism.

Conclusions:

• Long-term no-till cropping in the Amazon alters soil chemistry, driving microbial community homogenization.
• The soybean rhizosphere exhibits microbial selection, maintaining functional resilience despite agricultural pressures.
• Understanding rhizosphere dynamics is key to mitigating biodiversity loss and ensuring soil function in agricultural systems.