Carbon sink of soil inorganic carbon in arid regions and its contribution to carbon sequestration and emission reduction: A review

This paper is the result of environmental geological survey engineering.

Objective As a pivotal component of the global carbon cycle, the role of soil inorganic carbon in arid regions as a carbon sink cannot be ignored.

Methods This paper reviewed a large amount of literature related to soil inorganic carbon in arid regions at home and abroad, and focused on the confirmation of soil inorganic carbon carbon sink, carbon pool composition, source identification, and carbon sink influencing factors in a systematic summary.

Results The role of inorganic carbon carbon sinks in arid regions was confirmed along with the study of negative fluxes in arid regions, but the composition of its carbon pool is very complex, including liquid−phase carbon pools and solid−phase carbon pools. The liquid−phase reservoir is mainly in the form of Dissolved Inorganic Carbon in the groundwater of the arid regions; the solid−phase reservoir is the solid−phase Soil Inorganic Carbon in the soil profile, which is divided into Lithogenic Carbonate and Pedogenic Carbonate according to different genetic sources, and the latter is subdivided into carbonaceous soil−forming carbonate and silicic soil−forming carbonate . The SPC in PC has a real long−term stable carbon sink. The factors influencing inorganic carbon sinks are complex, including natural factors: climate, soil properties and depth, biological effects, soil−forming parent material, soil organic matter, etc.; anthropogenic factors: land use and land cover, agricultural management measures (irrigation and fertilization), etc.

Conclusions Soil inorganic carbon in drylands is extremely important for global carbon sequestration, and current research focuses on the identification of soil inorganic carbon sources, confirmation of carbon sink strength and quantification of carbon sequestration potential, as well as the clarification of influencing factors and assessment of the possibility of human intervention. Driven by the goal of achieving carbon peaking and carbon neutrality goals, the identification of soil inorganic carbon sources and influencing factors will be a research hotspot in the future within the global region, especially in arid and semi−arid regions. It will be a breakthrough point to solve the scientific problem of "Missing carbon sink", which will greatly promote the research of Global Carbon Cycle.