Effects Of Nutrient Addition On Soil Carbon Processes In Grassland Ecosystem

Since the industrial revolution, increased concentrations of greenhouse gases in the atmosphere caused changes in the global environment. It is a serious threat to human survival and the sustainable development of society and economy. It is becoming the world's great environment problems of intense attention. Grassland is one of ecosystems that are sensitive to global change and human activities. Its relationship between greenhouse gas flux and global environment is increasingly laid store by people. The study of greenhouse gases in grassland ecosystem and its influence mechanism is not only interact with an important link in our society, but also ensure our country's high-speed economic development, promote environment improvement and fulfill the basic research of the climate change convention.In this paper, Chinese Academy of Sciences Institute of Botany, Restoration Ecology Research Station Demonstration Thirteen experimental base in Xilin Gol League of Inner Mongolia Autonomous Region were studied. Nutrient additions on soil carbon grassland ecosystem Processes were studied through field tests and laboratory simulation. Through field experiments, Nutrient additions on the grassland ecosystem biomass and carbon storage and carbon fluxes of greenhouse gases have been studied. Nutrient additions on grassland ecosystem microbial biomass and organic carbon mineralization were studied through laboratory culture experiments. These studies will provide the basic data for improving the status of the greenhouse gas emissions through the use of grassland resources and revealing the "source / sink" transformation functions of greenhouse gases in grassland ecosystem.The main results obtained in this paper are as follows:1. After nutrient addition, most of all the differences between the treatments were not significant. The biomass of control is the lowest. Community biomass increased with the amount of added nutrients. Nutrient addition promoted plant growth, but the plant growth was inhibited more than a certain amount of N elements. Biomass underground layers showed gradual decreasing trend, liking the "inverted pyramid" type. Ground biomass mainly distributed in 0 10cm soil layer, the space for biomass 62.43% 52.13%. Total carbon storage plant, ground and underground carbon storage dynamics are the same with plant total biomass, aboveground and belowground variation.2. After adding nutrients, soil organic carbon did not significantly change and soil total N content increased significantly. Soil microbial biomass C and N changed significantly. Each the size of microbial biomass in order is: 10NPK> 20NPK> PK> control.3. After adding nutrients, organic carbon mineralization rate is different in different months. The CO₂ production rate of the treatment of 10NPK was significantly higher than other treatments. Soil CO₂ production rate of different treatments during incubation is consistent with the change of culture time on the number of function. The accumulation of different soil CO₂ emissions was different. Nutrients were added to promote the soil CO₂ emissions. Different treatments, the average cumulative mineralization was in the order of 10NPK> 20NPK> PK> control. Soil organic carbon mineralization rate was into a significant positive correlation with microbial biomass carbon.4. The variation of soil CO₂ emissions flux of different treatments in growing season is the same. Nutrient addition did not alter the changes of soil CO₂ emission patterns. In different treatments, the average emissions of 10NPK were significantly higher than other treatments, followed by the treatment 10N, and in high nitrogen fertilization conditions, CO₂ emissions, however, reduced. Different treatment for the average CH4 flux is negative, showing the sink of atmospheric CH4. Throughout the observation period, CH4 absorption capacity is strong at the start and the end of growing season. CH4 absorption capacity is weak in the month of June,July and August. Adding nutrients could promote the absorption of CH4. The ability of absorbing CH4 of the treatment of PK is the strongest.