The Distribution Pattern Of Carbon Reserve In Northern Tibet Alpine Grassland Ecosystem

Alpine grassland ecosystem environment quite atrocious, alpine cold, drought, atmosphere rarefaction, long time sunlight, ultraviolet radiation strong, soil layer shallow, soil airslake in low degree, high gravel content and vegetation abundance degree low. Study on distributing regulation about vertical grads and horizontal vegetation and soil carbon, as well as the influencing factors were discussed. The main research as follows:First, carbon reserve distribution regulation in vertical grads of alpine grassland1.The landform, climate, hydrology and altitude impact on alpine grassland ecosystem, followed the altitude, the vegetation types showed significant difference in northern Tibet alpine grassland. The aboveground carbon density and amplitude was low , and it gradually increasing followed the increasing altitude.2.The litter content in alpine grassland belongs to low level, as compared with total biomass, its ratio about 0.006, and the lowest ratio almost zero. The low coverage and biomass productive little litter, and in short growth period restricted the litter to engender.3.The belowground biomass was the main carbon sink in northern Tibet alpine grassland ecosystem. 40cm belowground biomass occupied total biomass 90%. Test the significant difference of altitude gradient belowground biomass, it showed that, 4460m belowground biomass was apparent higher than others, and concentrate in 4450m-4600m. Belowground and soil temperature had positive correlation, followed the increasing soil temperature the belowground biomass had crescent trend.4.The northern Tibet alpine grassland belongs to lower carbon density region in China, but the soil carbon density in different vertical altitude had high amplitude, its organic carbon density changed trend were: 4800m(15.27kgC·m^-2))>4907m(13.93kgC·m^-2)>4754m(13.74kgC·m^-2)>4579m(8.47kgC·m^-2)>4460m(7.92kgC·m^-2)>4501m(6.14kgC·m^-2)>4541m(5.93kgC·m^-2)>4709m(5.18kgC·m^-2).Second, carbon reserve distribution regulation in horizontal variation of alpine grassland.1.The northern Tibet alpine grassland of taking Cuoqin county, Anduo county and Ritu county as central, formed radialized aboveground biomass distribution pattern. And the highest in Cuoqin region, up to 23.78 gC·m^-2, in Anduo and Ritu region the content were between 19.02 gC·m^-2 and 19.88 gC·m^-2. 2.Multiple comparison analysis in horizontal litter did not reach significant difference level. The highest litter content was 0.296gC·m^-2, The lowest litter content was 0.1233gC·m^-2, and the average was 0.218gC·m^-2.3. 40cm soil total organic carbon density and soil bulk density had negative correlation, soil bulk density affect the distribution of soil total organic carbon density. The factor of temperature was the main climate affect forming of 40cm soil total organic carbon density.Correlation analysis on different composition of carbon in northern Tibet alpine grassland, it showed that hydrolytic carbon, humic and fulvic carbon, and activated carbon distribution in definite regulation, namely different composition carbon content in Anduo county Dangxiong county were higher than others, but had not significant difference in soluble carbon and inorganic carbon in all regions.