Precipitation change affects forest soil carbon inputs and pools: A global meta-analysis

Area of Science:

• Forestry
• Soil Science
• Climate Change Ecology

Background:

• Forests are critical for sequestering atmospheric carbon dioxide (CO2).
• Forest soil organic carbon (SOC) is a major terrestrial carbon pool.
• Uncertainty exists regarding SOC responses to precipitation changes, impacting future carbon storage predictions.

Purpose of the Study:

• To determine the effects of drought and irrigation on SOC pools, plant carbon inputs, and soil environments.
• To synthesize findings from global forest sites through meta-analysis.

Main Methods:

• Conducted a meta-analysis of 161 studies from 139 forest sites worldwide.
• Examined experimental data on drought and irrigation impacts on forest ecosystems.

Main Results:

• Overall forest SOC content remained unaffected by precipitation changes.
• Drought and irrigation significantly altered plant carbon inputs and soil properties.
• Drought may increase SOC stability via altered soil aggregate fractions.

Conclusions:

• Forest SOC insensitivity to precipitation change may stem from short experiment durations and biome-specific responses.
• SOC decline is probable under irrigation in drier temperate forests, which are underrepresented in studies.
• Further research is needed on distinct soil carbon pools and underrepresented forest types to predict future SOC storage accurately.