Simulated Nitrogen Deposition Impact On Greenhouse Gas Emissions Of Different Communities In Wugong Mountain

In recent years,nitrogen concentration has a rapidly increasing in the atmosphere,spreading to terrestrial and water ecosystems.However,this trend will continue for a long time.Grassland ecosystem is one of the most biggest ecosystem on the land.Which plays an extremely important role in Carbon and Nitrogen cycle.And the soils under the vegetation are the main emissions of CO₂,CH₄ and N₂O.Grassland ecosystem is sensitive to environmental change,small change in the soil carbon stock casued by Grassland environment may impact on global greenhouse gases emissions flux.This paper takes Wugong mountain meadow in Jiangxi province as the research object.Using field in-situ control experiment and static chamber method for measuring annual measurement of greenhouse gas emissions(CO_2,CH₄ and N₂O).Observing the variations of soil nutrient as well as soil temperature and humidity.Analysising the artificial simulated nitrogen deposition impact on greenhouse gas emissions and the soil nutrients of different communities.Exploring the relationships between soil temperature and humidity of the environmental factors with greenhouse gas esemissions of different communities in Wugong mountain.In order to provide the theoretical basis and data support to reduce greenhouse gas emissions of Wugong mountain.It has a far-reaching significance for diagnosising and restoring for mountain meadow degradation.（1）The effects of artificial simulated nitrogen deposition of Wugong mountain meadow for different communities in soil organic carbon and total nitrogen were not significant.In the short term,the nitrogen treatment on soil DOC,NH₄⁺-N and NO₃^--N have a significant effect.The show is that some nitrogen treatment and control nutrient content have significant differences in the growing season.On the seasonal change,showing the Fimbristylis dichotom in April nitrogen treatment extremely significant（P<0.01）increased soil p H value.The restored miscanthus in April nitrogen treatment significantly（P<0.05）decreased soil DOC content.The nitrogen treatment of native miscanthus significantly improved the soil NH₄⁺-N content in November.In June,Fimbristylis dichotoma NH₄⁺-N content of nitrogen treatment is significantly higher than control treatments,Fimbristylis dichotoma in June and November nitrogen treatment significantly improved the NO₃^--N level.（2）Nitrogen treatment no significant change of Wugong mountain meadow in different vegetation communities of CO₂,CH₄ and N₂O annual emissions.But significantly improved N₂O emissions of restored miscanthus,the other three communities had no significant effect of greenhouse gas in growing season.In terms of seasonal change,different communities in the growing season of CO₂ and N₂O emissions are higher than the non-growing season.Growing season the absorption of CH₄ is greater than the non-growing season.In the short term,the nitrogen treatment has a significant influence on greenhouse gases flux of different communities.In growing season,nitrogen treatment compared with the control treatment significantly improved the greenhouse gas flux.（3）Soil temperature and humidity of environmental factors with different communities has a significant correlation between greenhouse gas emissions.Fimbristy dichotoma,Carex chinensis,native miscanthus,restored miscanthus and CO₂emissions flux with 5cm ground temperature has a significant positive correlation,native miscanthus and CH₄ fluxes were significantly negative correlation.Carex chinensis CO₂ and CH₄ fluxes are significantly nonlinear correlated to the 5cm volumn soil moisture,and native miscanthus are significantly nonlinear correlation with CO₂,CH₄and N₂O emissions.All in all,artificial simulated nitrogen deposition in different communities of Wugong mountain meadow for soil nutrient and annual CO₂,CH₄ and N₂O emissions is not significant.But in a short time（different seasons）for its nutrient content or greenhouse gases flux have different degrees of influence.For environmental factors,soil temperature and humidity differs from the meadow community greenhouse gas flux to have different degree of linear or nonlinear relationship.Under the control conditions,the soil nutrient and the greenhouse gases flux of the bared soil are significantly different from those of other vegetation communities.Therefore,reducing human interference and restore vegetation productivity,covery of Wugong mountain soil nutrient and emission of greenhouse gas has extremely vital significance.