土壤有机碳汇内涵与核算方法辨析

在"碳达峰、碳中和"战略需求下,土壤有机碳汇作为生态系统碳汇的重要组成部分,土壤碳库容量以及如何开展土壤有机碳汇核算日益成为生态碳汇的研究热点。梳理了国内外土壤有机碳汇及核算相关研究成果,解析了土壤有机碳汇的概念内涵,提出了以稳定性有机碳作为土壤有机碳汇的表征指标及获取方法。从土壤发生学角度提出了土壤碳汇阈值的概念,土壤中有机碳的含量随着分解转化最终会达到动态平衡,此时稳定有机碳含量值约是常数,这个常数就是稳定碳库的库容,在特定的成土因素下,碳库的核算值不会超过平衡时的常态值。在客观上,体现在非人类干扰状态下不同土壤类型自然状态下的稳定性有机碳含量。参照土壤有机质平衡理论,提出了土壤碳汇核算的定量化方法,为土壤碳汇的度量和核算提供了一套技术思路。下一步土壤有机碳汇的核算应在科学研究基础上多角度凝聚共识,制定碳汇核算标准,确定不同尺度下可操作、可重复以及可复制的土壤有机碳汇核算技术与方法。

Analysis on the contents and methods of soil organic varbon dink

Soil organic carbon sink is an important part of ecosystem carbon sinks under the strategic requirement of "carbon peak and carbon neutralization". The capacity of soil carbon storage and conduction of soil organic carbon sink accounting have increasingly become the research hotspots on soil organic carbon sink. This paper reviews the domestic and foreign research results of soil organic carbon sink and accounting. On the basis of relevant research results, three research contents are proposed around soil carbon sink accountinganalyzes the concept and connotation of soil organic carbon sink, and puts forward the characterization index and acquisition method of soil organic carbon sink with stable organic carbon.From the perspective of soil genesis, the concept of soil carbon sink threshold is proposed. The content of organic carbon in soil will eventually reach a dynamic equilibrium with decomposition and transformation.At this time, the stable organic carbon content value is about a constant, which is the storage capacity of the stable carbon pool. Under specific soil forming factors, the calculated value of the carbon pool will not exceed the normal value at equilibrium. Objectively, it is reflected in the content of stable organic matter of different soil types under natural conditions under non-human interference. Referring to the theory of soil organic matter balance, a quantitative method for soil carbon sequestration accounting has been proposed, which provided a set of technical approaches for measuring and accounting soil carbon sink. In the next step, the accounting of soil organic carbon sinks should be based on scientific research to build consensus from multiple perspectives, formulate carbon sink accounting standards, and determine operable, repeatable and reproducible soil organic carbon sink accounting techniques and methods at different scales.