Effects Of Simulated Nitrogen Deposition On Greenhouse Gas Emission From Forest Soil In Changbai Mountain

In the CO2 and other greenhouse gases(such as CH4 and N2O),under the joint action of the earth's surface temperature increased 0.74?.At present,the rate of nitrogen deposition in most parts of the world is twice that of natural nitrogen deposition.In view of the situation of increasingly severe atmospheric nitrogen deposition,Changbai Mountain forest ecosystem,for example,using the method of artificial simulated nitrogen deposition,through the study of atmospheric nitrogen deposition on soil respiration in forest ecosystem in China and feedback mechanism,the influence of determining nitrogen deposition on forest the impact of greenhouse gases,thus to explore the nitrogen deposition on forest ecological system to alleviate the impact of the ability of the greenhouse effect.It provides basic data and scientific basis for accurately evaluating the response of soil greenhouse gases of the forest ecosystem in this region to the increase of nitrogen deposition in China,and then provides reference basis for alleviating global warming.In this experiment,the effects of control,short-term simulated nitrogen deposition and long-term simulated nitrogen deposition on forest main greenhouse gas and the relationship between greenhouse gas and soil physical and chemical properties and environmental factors were studied.The results are as follows:1.The total respiration rate of soil decreased after short-term and long-term simulated nitrogen deposition.With the increase of simulated nitrogen deposition time,the contribution rate of heterotrophic respiration to total soil respiration increased..2.In the growth season,soil respiration in the control,short-tern simulated nitrogen deposition and long-term simulated nitrogen deposition sample increased with the increase of 5oi1 temperature,and only the total soil respiration in the long-term simulated nitrogen deposition sample was significantly correlated with soil moisture.3.So on soil physical and chemical properties of soil bulk density and NO3--N and so on was positively correlated to soil respiration,soil ammonium nitrogen,pH,microbial biomass carbon and microbial biomass nitrogen and total carbon,total nitrogen,soil total carbon/nitrogen and dissolve organic carbon are negatively related with soil respiration,among them,only the microbial biomass nitrogen and the correlation between soil respiration.4.Short-term sample simulated nitrogen deposition and soil bulk density,soil ammonium nitrogen,nitrate nitrogen and dissolve organic carbon and soil respiration were positively correlated,pH,microbial biomass carbon and microbial biomass nitrogen and total carbon,total nitrogen and total carbon/nitrogen in soil and the negative correlation between soil respiration,among them,only the microbial biomass nitrogen and the correlation between soil respiration.5.Long-term sample simulated nitrogen deposition and soil physical and chemical properties of soil amnonium nitrogen,nitrate nitrogen,soluble organic carbon and microbial biomass nitrogen,and short-term sample simulated nitrogen deposition and soil respiration was positively related to relationship,soil bulk density,pH,microbial biomass carbon,carbon,total nitrogen and total carbon/nitrogen in soil,and negative correlation between soil respiration,but correlations are not significant.6.After simulated nitrogen deposition,soil CH4 absorption decreases,CO2 emission decreases,and N2O emission increases.The results of this study are as follows:greenhouse gases change significantly with the seasons in the growing season.Both short-term and long.term simulated nitrogen deposition inhibited soil respiration,but increased the proportion of heterotrophic respiration in total soil respiration.There is a significant exponential relationship between soil respiration and soil temperature.Soil moisture has little effect on soil respiration.Among the soil physical and chemical properties,only the microbial biomass nitrogen had a significant negative correlation with soil respiration of control and short-term simulated nitrogen deposition,while the other soil physical and chemical properties had little effect on soil respiration.Simulated nitrogen deposition inhibits soil CH4 absorption and CO2 emission,and promotes N2O emission.