Biochar, a stable carbon-rich material produced from the pyrolysis of biomass, has gained significant attention for its potential to improve soil health, increase productivity, and mitigate greenhouse gas (GHG) emissions. However, the effectiveness of biochar can vary across different land systems remain uncertain. This study investigates the land system-specific responses to biochar application, focusing on soil organic carbon (SOC), productivity, and GHG emissions in agriculture, forest, and grassland land systems.

 

I performed a meta-analysis of 22 studies to assess biochar's effects on these soil parameters. Biochar application increased soil pH by 5.24% (±0.022), with the greatest improvements observed in agricultural systems. The increase in SOC was most pronounced in grassland and forest systems, with SOC levels increasing by 28.7% (95% CI: 18.7%–39.5%), while the increase in agriculture was comparatively lower at approximately 16.2%. In terms of productivity, biochar application increased productivity by 23.4% (95% CI: 22.3–25.2%) across all land systems, with the highest response observed in grasslands.

 

Regarding GHG emissions, biochar increased CO₂ emissions by approximately 19.7% (95% CI: 9.3%–31.2%) across all land systems. However, biochar application reduced N₂O emissions by 31% (95% CI: –47% to –11%) in agricultural systems, where N₂O is a potent GHG. No significant differences in CH₄ emissions were observed across the land systems.

 

The analysis also identified key environmental factors influencing biochar efficacy. In agricultural systems, high temperatures and low precipitation compromised biochar’s effectiveness, reducing its beneficial effects by up to 30%. These findings highlight the importance of site-specific management strategies for optimizing biochar’s benefits across different land systems, particularly in terms of soil health, productivity, and GHG mitigation.