Stable Carbon Isotope Analysis Technology of Carbohydrates and Its Application in Soil Carbon Metabolism Research

Soil carbohydrates, such as glucose and fructose, are essential components of soil organic matter (SOM). They serve as the primary carbon and energy sources for soil microorganisms and play a crucial role in regulating SOM stability, both directly and indirectly. Despite their ecological importance, the transformation processes and forms of soil carbohydrates are still not well-understood, despite centuries of extensive study. The use of stable carbon isotopes as natural tracers offers distinct advantages over radioisotope techniques, including safety, cleanliness, and ease of control. As a result, stable carbon isotope analysis has been widely employed in soil carbon cycling research. The examination of carbon isotopic variation in carbohydrates using stable carbon isotope tracers contributes to our understanding of carbohydrate transformation and accumulation processes within the plant-soil-microorganism system. It also enhances our comprehension of soil carbon metabolism. This paper provides an introduction to the types, sources, and pretreatment methods of soil carbohydrates. Furthermore, it reviews the theory and methods of stable carbon isotope analysis as applied to carbohydrates and their relevance to the study of soil carbon cycling. Lastly, it offers a comprehensive summary of current research challenges and prospects for future advancements in soil carbon cycling research.