Soil multifunctionality is affected by the soil environment and by microbial community composition and diversity

Area of Science:

• Soil Science
• Microbiology
• Biogeochemistry

Background:

• Soil microorganisms are vital for carbon (C) and nitrogen (N) cycling.
• The influence of soil microbial community composition and diversity on biogeochemical cycles remains debated.
• Environmental factors shape microbial communities, impacting soil functions.

Purpose of the Study:

• To investigate the individual and combined effects of edaphic drivers on soil microbial communities.
• To assess the impact of edaphic factors and microbial communities on soil enzyme activities, and C and N processes.
• To determine whether soil C and N cycling are directly or indirectly controlled by the soil environment and microbial structure.

Main Methods:

• Soil samples were collected from three land uses (cropland, grassland, forest) on two bedrock types (silicate, limestone).
• Bacterial/archaeal and fungal community composition were analyzed using high-throughput sequencing of 16S rRNA and ITS1 regions.
• Statistical analyses, including partial Mantel tests, were used to explore relationships between edaphic variables, microbial communities, and soil functions.

Main Results:

• Edaphic factors significantly shaped both bacterial/archaeal and fungal communities, with stronger effects on bacteria/archaea.
• Soil C processes were directly influenced by the soil environment, independent of microbial composition.
• Soil N processes were significantly related to bacterial/archaeal community composition and microbial diversity, indicating indirect environmental control.

Conclusions:

• The soil environment directly controls C cycling and indirectly influences N cycling by structuring microbial communities.
• Both edaphic drivers and microbial community composition/diversity are critical for soil C and N cycling.
• Understanding these interactions is key to managing soil functions and ecosystem health.