Effects of Nitrogen Addition on Plant-Soil-Microorganism Stoichiometry Ratio of Forest Ecosystem: A Review

Although the problem of increasing atmospheric nitrogen deposition rate caused by human activities has been improved, it still affects the material cycle of forest ecosystems. The effects of simulated nitrogen application on the stoichiometric ratio of forest ecosystems in China are mostly focused on the single analysis of plants, soil and microorganisms, and there are few studies on the stoichiometric characteristics and coupling relationship of plant-soil-microbial carbon (C), nitrogen (N) and phosphorus (P). In this paper, we summarized the response of plant-soil-microorganism C, N and P stoichiometry characteristics after exogenous nitrogen input by integrating previous research results. The results showed that low concentration of nitrogen application was beneficial to the accumulation of soil main nutrients and microbial biomass, and promoted the absorption and utilization of plant and microbial nutrients, while high concentration of nitrogen application was the opposite. However, for C and P elements, different results are shown. C element increases or does not change with the input of exogenous nitrogen, while P element is full of uncertainty, showing three results of increase, constant or decrease, which is mainly due to the limitation of nutrient elements and the change of environmental factors. Through the systematic integration of this paper, the lack of knowledge in the field of plant-soil-microbial C, N and P stoichiometric characteristics coupling in forest ecosystems is supplemented, which can provide a theoretical basis for further understanding and understanding the impact of nitrogen deposition on ecosystem biogeochemical cycles in the future.