[Effects of Simulated Nitrogen Deposition on Soil Organic Carbon Fractions and Carbon Pool Management Indicators in Mid-subtropical Plantations].

To study the characteristics of soil organic carbon （SOC） components and carbon pool management indicators of a plantation after continuously simulating nitrogen deposition for five years and to explore the relationship between soil organic carbon components and soil environmental factors, it is helpful to understand the influence of nitrogen deposition on soil quality and SOC pool stability and provide a scientific basis for sustainable management of subtropical forest ecosystems and protection of the soil environment. In a long-term positioning test of simulating nitrogen deposition from 2018, four different treatments were selected： CK [0 kg·（hm·a）], low nitrogen LN [50 kg·（hm·a）], middle nitrogen MN [100 kg·（hm·a）], and high nitrogen HN [150 kg·（hm·a）]. The contents of SOC, light fraction organic carbon （LFOC）, heavy fraction organic carbon （HFOC）, easily oxidized organic carbon （EOC）, dissolved organic carbon （DOC）, particulate organic carbon （POC）, microbial biomass carbon （MBC）, soil physicochemical properties, carbon cycling-related enzyme activity, and carbon pool management indicators following the different treatments were measured.