Transformation of soil organic matter subjected to environmental disturbance and preservation of organic matter bound to soil minerals: a review

Purpose: Soil organic matter is an important part of the earth’s carbon cycle, of which stability is related to its own obstinacy, and environmental disturbance also plays an important role. Soil minerals can combine with organic matter, preventing organic matter decomposition. Understanding the impact of environmental change and the mechanism of mineral stabilization of soil organic matter is important for evaluating global carbon storage and recycling. Materials and methods: We review the input, transformation on the soil organic matter composition, and the influence of environmental factors on soil organic matter stabilization and discuss the mechanism of mineral stabilization on soil organic matter, especially the role of iron. Results and discussion: At present, there are many studies on the stabilization mechanism and stable medium of soil organic matter. Environmental changes such as pH, moisture, temperature, and fertilization have a significant impact on the stabilization of soil organic matter, which affect the adsorption, co-precipitation of soil organic matter, or damage the soil structure, resulting in the re-exposure of organic matter. The stabilizing effect of minerals on soil organic matter is discussed, especially iron. Conclusions: This review gives an overview of the effect of environmental disturbance on the stabilization of soil organic matter and the protection of minerals to soil organic matter. The current research focuses on the adsorption of some organic matter or organic matter functional groups by minerals. However, this does not represent the real situation in soil. The composition and stabilization mechanisms of soil organic matter are complicated and ambiguous. It is critical to develop in situ analysis techniques to further study the stabilization mechanism of soil organic matter. Meanwhile, establishing mathematical models to simulate the changes of environment is conducive to forming a better understanding of the stability of organic matter. These studies can not only solve the problem of the “black box” of soil organic matter, but also promote further understanding of the impact of soil organic matter on the global environment and carbon cycle.