Carbon Sequestration Strategies in Soil Using Biochar: Advances, Challenges, and Opportunities.

Area of Science:

• Environmental Science
• Soil Science
• Biogeochemistry

Background:

• Biochar, a stable carbon-rich material from biomass pyrolysis, is a key strategy for soil carbon sequestration and climate change mitigation.
• Its effectiveness depends on its structure and interactions with soil components, influencing carbon cycling.
• Understanding these interactions is vital for optimizing biochar's role in soil carbon storage.

Purpose of the Study:

• To review advances and identify key issues in biochar application for soil carbon sequestration.
• To address challenges and knowledge gaps hindering biochar's effective use.
• To provide future research directions and recommendations for biochar implementation.

Main Methods:

• Literature review focusing on five critical aspects of biochar application in soil.
• Analysis of biochar terminology (pyrochar, hydrochar), soil stability, carbon flux and speciation, greenhouse gas emissions, and application barriers.
• Synthesis of current knowledge and identification of research needs.

Main Results:

• Identified key issues including terminology, biochar stability, carbon cycling impacts, nitrogenous greenhouse gas emissions, and application barriers.
• Highlighted the complex abiotic and biotic reactions influencing biochar's carbon sequestration potential.
• Emphasized the need for mechanistic understanding and long-term field studies.

Conclusions:

• Mechanistic understanding of biochar-soil interactions and long-term field studies are essential for accurate carbon sequestration assessment.
• Standardization of biochar production and application, along with defined application thresholds, is urgently needed.
• Comprehensive life cycle assessments are required to evaluate the total benefits of biochar beyond soil carbon sequestration.