Soil Inorganic Carbon Distribution Characteristics In Typical Grassland In North Slope Of Tianshan Mountains Of Xinjiang

Soil inorganic carbon(SIC) distribution of arid grassland plays an important role to the research of the grassland ecosystem carbon cycle in arid areas. In this paper, based on eight kinds of typical grassland soil profile data of North Slope of Tianshan Mountains, Analyzed the SIC distribution and its influencing factors of different grassland types and soil types. This has important implications for studies of grassland ecosystem carbon balance and carbon cycle mechanism.The results showed that:(1) Within one meter, SIC contents of Alpine meadow, Temperate mountain meadow, Temperate meadow steppe, Temperate steppe, Temperate desert steppe, Temperate steppe desert, Temperate desert and Lowland saline meadow were : 0.02, 7.72, 9.74, 8.55, 9.46, 7.38, 6.30, 15.00g·kg-1; while the SICD were0.01, 7.98, 10.18, 7.13, 7.57, 5.12, 6.80, 14.20 kg·m-2, the average soil inorganic carbon density of eight types grassland is 7.37 kg·m-2, and the biggest coefficient variation of SICD appears in 0-20 cm layer.(2)Characteristic difference of soil inorganic carbon distribution of different types of grassland are obvious, Alpine meadow soil inorganic carbon content and density have no obvious change with the deepness of soil deepen; soil inorganic carbon content of Temperate mountain meadow with deeper soil depth showed first increased then decreased, while it’s SICD has manifested gradually increasing trend, mainly stored in 50-100 cm, accounted for 64.84%.Within one meter layer; along with the deepening of the soil depth, SIC content and SICD of other six kinds of grasslands showed the trend of first increase then decreases, mainly distributed in 0-50 cm layer, the proportion is 50.04 to75.87%.Distribution characteristics of different soil types have obvious difference. As deepness of soil deepen, SIC content and SICD of Alpine meadow soil and Sand soil have no obvious, In 0-70 cm soil layer, gray brown desert soil SIC content has no obvious change, the underlying 70-100 cm SIC content is the lowest, while SICD showed the trend of first increased then reduced; SIC content and SICD of salt meadow soil first increased then reduced; The performance of chernozem, gray desert soil, chestnut soil, and brown calcic soil SIC content are first increased and then decreased as the deepness of soil deepen, however SICD have the increase trend. Within one meter, Aeolian sandy soil, alpine meadow, chernozem, gray desert soil, gray-brown desert soil, chestnut soil, saline meadow soil, brown soil SIC contents were: 2.87, 0.01, 8.34, 10.81, 4.86, 8.44, 15.04, 8.61 g.kg-1, respectively, SICD were: 4.25, 0.006, 8.24, 10.50, 3.70, 7.44, 14.20, 7.4, 7.17 kg m-2, with an average density of 7.18 kg m-2.(3)Correlation between pH and SIC content had very significant positive on the surface of 0-10 cm layer, reached very significant negative in 70-100cm; while as for SICD extremely significant positive at 0-20 cm, significant positive at 20-50 cm. Correlation between soil bulk density and SIC content with soil depth increases, reached significant negative in 30-50 cm, very significant negative in 50-100 cm, as for SICD showed significant positive at 0-5cm, significant negative at 70-100 cm. Within 0-30 cm and 0-50 cm, SIC content and SICD are in negative correlation between the annual precipitation and altitude.(4) The north slope of tianshan mountain 0 to 30 cm, 0 to 50 cm, 0 to 100 cm soil layer SICD from west to east, first the trend of increase after decreases and then increases, both in JingHe lowland saline meadow areas SICD reached maximum, alpine meadow in urumqi, south and north of the genetic SICD reached lowest.