Land use driven change in soil pH affects microbial carbon cycling processes

Area of Science:

• Soil science
• Microbiology
• Ecology

Background:

• Soil microorganisms regulate soil organic matter accumulation and decomposition, influencing carbon cycling.
• Understanding microbial mechanisms is crucial for developing land management strategies to enhance soil carbon storage.
• Current knowledge gaps hinder effective soil carbon sequestration efforts.

Purpose of the Study:

• To investigate the relationship between microbial ecophysiological traits and topsoil carbon content.
• To determine how land use intensification affects soil carbon under varying pH conditions.
• To elucidate the distinct microbial mechanisms governing carbon dynamics in different soil types.

Main Methods:

• Empirical testing of microbial ecophysiological traits across diverse soils and land uses.
• Analysis of topsoil carbon content in relation to microbial community characteristics.
• Comparative study of carbon dynamics in low-pH and near-neutral pH soils under land use intensification.

Main Results:

• Distinct pH-dependent microbial mechanisms control soil carbon accumulation.
• In low-pH soils, increased pH above ~6.2 due to land use intensification led to carbon loss via enhanced decomposition.
• In near-neutral pH soils, intensification caused carbon loss linked to reduced microbial biomass and growth efficiency.

Conclusions:

• Soil pH significantly influences microbial responses to land use change and subsequent carbon storage.
• Less-intensive management in near-neutral soils may optimize carbon storage via microbial growth efficiency.
• In acidic soils, microbial growth limitations are a key factor controlling decomposition rates and carbon sequestration potential.