Research progress on soil organic matter fractions-Visual analysis based on CiteSpace

Soil organic matter (SOM) is an important component of soil, which is of great significance in the study of the global carbon cycle. SOM content determines soil fertility, while the fractionation, stability and transformation process of SOM have emerged as a key research focus. In order to examine the research trajectory of SOM fractions, this paper analyzes the research progress on SOM fractions with CiteSpace software, and future research field is proposed. The results show that SOM fractionation is generally divided into physical, chemical and biological fractionation methods. A total of 2 429 papers have been published since 1968. The number of published papers increased rapidly since 1990, with an average annual growth rate of approximately 8.15%. Currently the research of SOM fraction is in a stage of rapid development. Its research mainly focuses on the separation methods of SOM fractions, the influence of land use patterns on SOM fractions, and the decomposition rates of different SOM fractions. Future global research on SOM fractions will focus on the impact of SOM fractions on the ecological environment and food security, and the response of SOM fractions to future climate change should be addressed simultaneously.