生物质炭特性及其对土壤性质的影响与作用机制

生物质炭（biochar）是一种碳含量高、比表面积大、孔隙度高且吸附能力强的土壤改良与修复材料，可通过物理、化学和生物方式作用于土壤，但其影响和作用机制随土壤性质和生物质炭类型不同而异。从生物质炭组成、比表面积和孔隙度、酸碱度及表面官能团等特性与原料和制备工艺关系入手，结合土壤和生物质炭类型，综合阐述了生物质炭添加在改善土壤结构、提高土壤肥力、调节土壤酸碱度、修复污染土壤、增强生物活性和促进养分转化等方面的作用。发现生物质炭通过填充扩容、孔隙截留、胶结凝聚、物理吸附、化学吸附、离子交换、配位络合、共沉淀、微生物介导等方式作用于土壤，实现土壤改良和修复。从物理、化学和生物3方面分类阐述了生物质炭对土壤的影响和作用机制，同时提出未来可重点关注生物质炭改性与制备工艺、不同生物质炭混施比例及施用后的环境风险评估等方面。

Characteristics of biochar and its effects and mechanism on soil properties

Biochar is a kind of soil improvement and remediation material with high carbon content, specific surface area, porosity and adsorption properties. It can influence the soil through physical, chemical and biological ways, but the influence and mechanism vary with soil properties and biochar types. The composition, specific surface area and porosity, pH and surface functional groups of biochar and the raw materials and charring technology of the biochar were summariezed. Effects of biochar addition on soil structure improvement, soil fertility improvement, soil pH regulation, contaminated soil repairment, biological activity enhancement and nutrient transformation promotion were comprehensively generalized. It was found that the soil was remediated or improved by biochar mainly through filling and expansion, pore interception, cementation and coagulation, physical adsorption, chemical adsorption, ion exchange, coordination and complexation, coprecipitation, microbial mediation and so on. The effects and mechanism of biochar on soil were clarified from physical, chemical and biological aspects, respectively. The modification and charring technology of biochar, the proportion of mixed application of biochar and the environmental risk assessment after biochar application in the future should be the key research contents.