基于整合分析方法评价我国生物质炭施用的增产与固碳减排效果

Evaluating the effects of biochar amendment on crop yield and soil carbon sequestration and greenhouse gas emission using meta-analysis

通过搜集公开发表的文献资料,运用整合分析方法(Meta-analysis)研究生物质炭施用对我国农作物产量和土壤固碳减排潜力的影响。结果表明,生物质炭施用显著提高了作物产量,平均增产幅度为15.1%,其中旱作作物平均增产16.4%,水稻增产10.4%。试验土壤和生物质炭材料本身的理化特性与田间管理方式均会影响生物质炭施用下作物的增产幅度。土壤酸碱度和质地是影响增产幅度的重要因素:强酸性土壤中施用生物质炭作物增产幅度显著高于中性和碱性土壤;黏土和砂土中施用生物质炭作物增产幅度显著高于壤土。生物质炭生产过程中的炭化温度对作物产量有重要影响,当炭化温度高于550℃时,作物增产不显著。生物质炭施用显著降低了农田土壤氧化亚氮(N_2O)排放量和稻田甲烷(CH4)排放量,平均降低幅度分别为13.6%和15.2%。土壤酸碱度和质地显著影响N_2O减排幅度;生物质炭在中性和碱性土壤中的减排效果显著高于酸性土壤,而在强酸性土壤中N_2O减排效果不显著;不同质地土壤中N_2O的减排效果表现为壤土>砂土>黏土,壤土减排量达33.9%。氮肥施用量高于150 kg·hm-2时,N_2O减排效果显著。稻田土壤施用生物质炭N_2O减排效果优于旱地。土壤质地和酸碱度显著影响稻田CH4排放对生物质炭输入的响应,强酸性或砂性土壤中施用生物质炭CH4减排效果明显,其减排幅度分别为46.1%和25.9%。我国农田中施用生物质炭,有利于达到增产和固碳减排的效果。今后生物质炭的农田施用应优先选择施用到酸性、黏性或砂性等肥力较差的土壤中,优先选择旱作农田;生物质炭制备时应将炭化温度控制在550℃以下。

In this study, a meta-analysis was conducted to investigate the effect of biochar amendment on crop yield, soil carbon sequestra-tion and greenhouse gas mitigation potential. The dataset was derived from field studies conducted in China's Mainland. The papers werepublished in either Chinese or English. This study showed that biochar soil amendment significantly increased crop yield by increased cropyield by 15.1% on average, whereas rice yield was increased by 10.4% and the grain yield of dry land crops was increased by an average of16.4%. The changes in grain yield following biochar amendment were influenced by soil and biochar properties as well as soil managementpractices. With regards to experimental soils acidity and texture were important factors influencing the response of crop yield to biocharamendment. Substantially greater yield increases were observed in soil with very low pH and clayey and sandy texture. In addition to soilproperties, biochar properties also influenced the response of crop yield to biochar amendment. No yield increases were observed when agri-cultural soils were amended with biochar produced at a high temperature(>550 ℃). Biochar amendment decreased nitrous oxide(N2O)emission by 13.6% in dry crop land and decreased methane(CH4)emission from paddy soil by 15.2%. Soil acidity and texture were foundto be important factors that regulate the response of N2O emission to biochar amendment. In strongly acid soils, the addition of biochar hadno effect on N2O emission, whereas in neutral or alkaline soils, biochar significantly decreased N2O emission. In terms of soil texture, the di-minishing effects of biochar were in the order of loam > sand > clay. In loamy soils, biochar amendment decreased N2O emission by 33.9%.Nitrous oxide emission decreased significantly in soils amended with biochar under a nitrogen fertilizer application rate higher than 150 kg·hm-2. In rice paddies, biochar amendment decreased N2O emission by 24.4%, which was significantly higher than the value in dry croplandsoils. Soil texture and pH significantly affected the response of CH4 emission to biochar amendment. In strongly acidic or sandy soils, bio-char amendment markedly decreased the emission of CH4. In soils with a sandy texture, biochar decreased CH4 emission by 25.9%. In con-clusion, our study shows that biochar soil amendment can increase crop yield and decrease greenhouse gas emissions in China ′s croplands.In the future, we suggest that it will be preferable to apply biochar to soils with lower fertility, such as acidic, clayey, or sandy soils, and todry crop land rather than paddy soils. Furthermore, biochar produced at a pyrolyzing temperature lower than 550 ℃ would be more suitablefor the amendment of agricultural soils.