土壤碳库构成研究进展

土壤碳库是陆地生态系统中最大的碳库。土壤碳库的构成影响其累积和分解,并直接影响全球陆地生态系统碳平衡,同时也影响土壤质量变化。弄清土壤碳库的组分及构成,是进一步研究土壤碳库变化机制的关键。综述了土壤碳库的组分和构成,对有机碳库进行不稳定性有机碳库和稳定有机碳库归类,描述各类碳库的性质,并对各类碳库的分析测定方法进行了评述。提出在土壤碳构成中增加黑碳和煤炭(碳)以完善土壤有机碳构成框架。在未来研究中,应加强土壤无机碳及湿地土壤和新开发新复垦的重构土壤碳库构成及变化,各类碳库化学构成,交叉重叠的定量关系,碳库之间的转化及在土壤中的迁移,黑碳对土壤碳库稳定性及土壤质量的影响,煤开采扰动区煤炭(碳)对土壤质量的影响及环境效应等科学问题的研究。

A review of the composition of soil carbon pool

The soil carbon pool is the biggest one in the terrestrial ecosystem. The composition of soil carbon pool influences carbon accumulation and decomposition, and directly controls global terrestrial carbon balance, and influences soil quality. Making clear the constitutes of soil carbon pool is the key process in revealing the mechanism of soil carbon pools change. This paper overviewed the structure and composition of the soil carbon pools. Soil carbon pools include soil inorganic carbon pool and soil organic carbon pool. Soil inorganic carbon pool includes HCO₃^- in soil solution,CO₂ in soil air, and CaCO₃ in soil. And CaCO₃ is the main component in soil inorganic carbon pool. Soil inorganic carbon pool can influence soil organic carbon pool by affecting composition of soil aggregates, microbial activity, soil pH, and soil organic matter decomposition rate. Soil organic carbon is a very complex continuous mixture, which includes a variety of organic carbon fractions and forms with different nature. And the content of all kind of soil organic carbon affects the transformation of soil carbon pool and thereby influences soil quality and carbon cycle in terrestrial ecosystem. Soil organic carbon pools are categorized into soil labile organic carbon pool and soil stable organic carbon pool. Among them, soil labile organic carbon can turnover within a certain time, and can be utilized by plant and microorganism, and have a major impact on the carbon balance. Soil labile organic carbon is also named soil activated organic carbon or effective carbon by some authors, and includes terms as available carbon (AC), dissolved organic carbon (DOC), water soil organic carbon (WSOC), readily oxidation carbon (ROC), microbial biomass carbon (MBC), biodegradable carbon, light fraction organic carbon (LFOC), particulate organic carbon (POC) and so on. Black carbon (BC) and coal carbon are suggested to be categorized into soil organic carbon pool to perfect the frame of soil organic carbon pool composition. Black carbon is a C-rich organic material derived from incomplete combustion of fossil fuels and vegetation and from weathering of graphitic C in rocks, and very stabile. Black carbon captures and sequesters carbon from the bio-atmospheric cycle, which, in the long term, reduces greenhouse gas emissions and thus mitigates the greenhouse effect. Meanwhile, resistant black carbon amendation increase soil organic matter, thus regulating soil structure and enhancing soil fertility. Because of its high adsorption capacity, black carbon adsorbs organic pollutants, heavy metals, nutrients to decrease ecosystem risk. The coal (carbon) in the surface layer soil mainly come from outside source; include garbage, filling, atmospheric sedimentation and so on. The coal mine area is usually the district absorbing the most coal (carbon). In future studies, we should strengthen the researches on the scientific issues including the chemical composition, overlapping quantitative relationship of the soil organic carbon pools, transformation and migration of soil organic carbon in the soil, the impact of black carbon on the stability of the soil carbon pool and soil quality, the impact of coal (carbon) on soil quality and environmental effects in the coal mining disturbed zone, and organic carbon change and mechanism in newly developed soil, reclamation soil and reconstruction soil.