Experimental Study On The Effect Of The Nitrogen Deposition On The Tundra Vegetation, Changbai Mountain

The vegetation types are low on Changbai Mountain alpine tundra, and thedominant species are mainly Rhododendron aureum and Vaccinium uliginosum. Inrecent years, Deyeuxia. angustifolia herbs continue to invade into the tundra, Theinvasion of plaques are gradually expanding, which forming competition withRhododendron aureum and Vaccinium uliginosum, and changing the vegetationcomposition of the area. Deyeuxia. Angustifolia herbs strong competition from othershrub vegetation, and the growth situation is better than Rhododendron aureum andVaccinium uliginosum in the competition.This paper explores effects of nitrogen deposition on the tundra vegetation ofChangbai Mountain. We make the imitate nitrogen deposition test on Rhododendronaureum palque、Vaccinium uliginosum palque and Deyeuxia. angustifolia palque inthe alpine tundra of Changbai Mountain. We measured the relative plant height,number of patches，relative plant aboveground biomass, leaf area index, NDVI index,underground biomass, plaque index such as soil properties in three kinds of nitrogendeposition treatment. And we comparative analysis the effects of nitrogen depositionon the growth of three vegetation patches. The results show that：First, experimental observations show that, there were new species in threepalques, which explained the nitrogen deposition only impact Changbai Mountaintundra vegetation community, growth, but do not promote the formation of newspecies.Second, Rhododendron aureum palques tested index was showed：low nitrogendeposition﹥natural nitrogen deposition﹥high nitrogen deposition,which indicatesthat the appropriate amount of nitrogen deposition in favor of Rhododendron aureumgrowth, and excessive nitrogen deposition will inhibit them to grow and develop. Thesoil indexs are the most high in three kinds of palques.Third, in nitrogen deposition conditions, Vaccinium uliginosum plaque indexesdecreased with the increasing nitrogen deposition amount; The soil indexes are thelowest in three kinds of palques.Fourth, nitrogen deposition increases is benefit for Deyeuxia. angustifolia growth. Along with the increase of nitrogen deposition, Deyeuxia.angustifolia plaquemeasured indexes increased. The soil indexes are well situated,which are befitted forthem growth. Fifth, nitrogen deposition changes the phenology of three plaques. Nitrogendeposition moves up the sample vegetation biggest growth period, and advances aboatone month.Sixth, nitrogen deposition increases the content of nitrogen in soil, The contentof organic nitrogen in the soil of the alpine tundra of Changbai Mountain is far higherthan the content of inorganic nitrogen, and the content of nitrate nitrogen is far lowerthan the ammonium nitrogen content; With the nitrogen input, soil total phosphoruscontent is reduced.