[Impact of Biochar Properties on Greenhouse Gas Emission Reduction and Yield Improvement in Farmlands of the Three Major Staple Crops].

Abstract

This study evaluated the impact on greenhouse gas emissions and crop yields of applying biochar with varying properties in the cultivation of the three major staple crops of rice， wheat， and maize with the aim of providing insights and strategies for promoting both emission reduction and yield enhancement in ecological agriculture. Based on 252 published papers from databases such as the Web of Science and CNKI， comprising 1 707 sets of experimental data， a Meta-analysis using a random effects model was conducted. The natural logarithm of the response ratio （lnR） was used as the effect size to quantify the impact of different biochar properties on greenhouse gas emissions， crop yield， and soil physicochemical properties. The results showed that different biochar properties had significantly different effects on greenhouse gas emissions. Overall， biochar presented the most significant effect on reducing N₂O emissions， with medium-temperature pyrolyzed （401-550℃） biochar reducing N₂O emissions in wheat fields by 33.94%， followed by the reductions of CH₄ and CO₂. High-temperature pyrolyzed （551-750℃） biochar reduced CH₄ emissions in rice fields by 19.74%. Biochar application significantly improved soil physicochemical properties， including increasing soil carbon and nitrogen levels， pH， and cation exchange capacity （CEC）. By enhancing soil fertility and improving soil structure， biochar significantly increased the yield of the three staple crops， with low C/N ratio （51-100） and low pH biochar showing the most notable yield improvements. By significantly reducing N₂O emissions and moderately reducing CH₄ emissions， biochar significantly lowered the global warming potential （GWP） and greenhouse gas emission intensity （GHGI） of farmlands. The study concluded that the reasonable application of different types of biochar effectively reduces greenhouse gas emissions and increases crop yields， achieving the dual benefits of emission reduction and yield enhancement. In practical applications， the configuration of biochar should be optimized based on crop type， soil conditions， and other factors.