Impacts of Pyrolysis Temperature on Biochar Properties and CO2 Emission of Soil Amended with Biochar

This study aims to document the hypothesis that pyrolysis temperature affects biochar properties and govern soil CO₂ emission when returned to soil as amendment. Biochar properties were investigated at different temperatures of 300 °C, 500°C, and 700 °C. Incubation experiment of soil with biochars was conducted over 46 d. Increasing temperature may strengthen the carbon enrichment in biochar, form advanced pore structure. The fixed carbon and ash relative contents increased, and the alkalinity and aromaticity became stronger with rising pyrolysis temperature. The effect of biochar on soil CO₂ emission lies in the combined actions of biochar properties, increasing temperature may convert the positive effect on soil CO₂ emission into a negative effect, thereby sequestrating carbon and improving soil organic carbon.