Abstract: Carbon and nitrogen leaching and seepage with subsurface flow is one of the main paths of soil carbon and nitrogen loss. However, as great challenges lie in direct observation, soil carbon and nitrogen leaching related research is relatively lagging behind. Especially due to the complexity of the soil subsurface flow, some problems have not been fully elucidated. In this paper, the characteristics and observation methodologies of soil carbon and nitrogen leaching under the influence of soil, environment and subsurface flow were first summarized, and numerous complicated factors demonstrated to affect carbon and nitrogen leaching, where the influence of rainfall and soil properties were pre-dominant. Field measurement could reflect the natural process of leaching, the indoor experiment could effectively quantify the influential factors on leaching, and the mathematical model could help understand the physical mechanism of carbon and nitrogen leaching by simulating water flow and matter transport in porous media. Future research could combine these methods to achieve a better research effect. The aim of this paper was to provide a certain understanding of the role of carbon and nitrogen in the process of matter cycling and nutrient transfer, and to provide a scientific basis for better regulation of the dynamics of carbon and nitrogen mineralisation, sequestration, leaching and plant uptake in future ecosystems.

Key words: Carbon leaching, Nitrogen leaching, Subsurface flow