The Study Of Soil Organic Carbon(N) Storage And Circulation Patterns In Ebinur Lake Wetland

Wetland is an integral part of the ecosystem and has received tremendous attention in the research, especially in arid zone. The research on it plays a very important role for the sustainable development of ecosystem. Field investigation, analytical chemistry and geostatistics method were employed to ascertain differentiation regularity of organic carbon and related elements of the soil, analysis the formation mechanism, calculate the inventory of organic carbon and total nitrogen, and construct the model of organic carbon cycle under different vegetation coverage in Ebinur Lake wetland.This study not only can greatly enrich theoretical research about wetlands in arid area,but also reveal sequestration mechanisms and carbon sequestration potential of wetland ecosystems, understand wetlands regulator function, evaluate potential environmental effects of ecosystems, and provide significance to rational utilization and coordinate the relationship between the environmental protection and the sustainable development of regional economy. Through the above research,the main conclusions are as follows:The statistical characteristics and distribution rules of soil nutrients of the Ebinur Lake wetland: As goes down the soil layer,there was significantly decline for soil organic carbon, total nitrogen, available potassium;variation of available phosphorus and hydrolytic nitrogen were relatively consistent,Showing decrease and then increase from top to bottom. The overall situation for the soil nutrient is low. The nutrient variation coefficient of soil organic carbon analysis shows: all soil layers showed strong variability, hydrolytic nitrogen(0-60cm) exhibits strong variability,(60-80cm) presented moderate variability;available P belonged to the medium variation;available K showed moderate variability;total nitrogen( 0-80cm) also showed strong variability. As can be seen from the chart about Frequency analysis with different nutrient,the samples in the different soil layers are corresponding to different distribution frequency, except for available K, the other indexes are in similar pattern,The variogram parameters of soil nutrient indicates there is a strong spatial autocorrelation,in this study more contribution to spatial variability comes from space heterogeneity of autocorrelations. The correlation coefficient R2 for the organic carbon,hydrolytic nitrogen,available phosphorus,available potassium were above 0.5,which suggests the fittings with the employed modes are valid. From the spatial graphics can be seen the higher contents are in southwestern. Therefore,factors such as non-contiguous terrain features,strong wind at Alashankou and human factors are presumably mainly responsible for the spatial variability of soil nutrients.The conclusions involved organic carbon accumulation of soil suggests that the extent of decline for organic carbon with increasing depth vary with 7 different vegetation coverage. On the surface of soil, there are greatest difference between grassland. For example, organic carbon of soil covered by salinized meadow is greatest, and 6-7 times that of other types of soil organic carbon content. The 20-100 cm soil layer, the differences of the seven types of soil organic carbon content decreases gradually. Pricipitation and temperature are the important factors affecting the content of soil organic carbon under different vegetation coverage. Through nearly 55 years of meteorological data associated with organic carbon analysis shows the correlation between average annual pricipitation and 20-40 cm layer is strong, and weak correlation with other types. The average annual temperature has strong correlation with 20-40 cm layer while weak correlation with other layers. The correlation between the average annual pricipitation and organic carbon density of 20-60 cm of soil is strong, and relatively weak correlation with other types. The decreasing order of organic carbon accumulation in the Ebinur Lake wetland is following as, Small trees in desert> salt meadow> dry lakebed> shrub desert> halophyte shrub> desert riparian forest> alpine coniferous forest. The total organic carbon accumulation for 7 types of soil are 7086862.83 Kg C.The conclusions involved nitrogen accumulation of soil as follows: the low content of total nitrogen, and The coefficient of variation showed the majority of different soil types, soil belongs to the medium variation, the individual soil showed a strong variation and weak mutation. The content of total nitrogen decreases with increasing depth of soil for 7 types of vegetation coverage, but they are different, especially salinized meadow. In the distribution pattern of the total nitrogen content of different soil layers depends on the types of vegetation, the difference of soil total nitrogen content between each vegetation type is mainly manifested in surface 0-20 cm of soil. Pricipitation and temperature are the important factors affecting the content of total nitrongen under different vegetation coverage. Through nearly 55 years of meteorological data associated with total nitrogen analysis shows there are maximum determination coefficient and strong correlation between the average annual pricipitation and temperature with soil nitrogen content of 0-20 cm layer, but relatively weak correlation with other layers. There is a very strong correlation between annual average temperature and nitrogen density of soil in 80-100 cm layer, between the annual average pricipitation and nitrogen density of soil in 20-40 cm layer also showed a strong correlation, while other soil coefficient of determination is smaller. The sequence of total nitrogen accumulation is salinized meadow > shrub >Small trees desert > cold damp coniferous forest > dry lakebed > desert riparian forest > Salt shrub. The total nitrogen accumulation of seven different types of soil is 4691903 Kg N.Simulation results by using the BGC model, involved the carbon cycle process of Haloxylon shrub in the Ebinur Lake wetland, demonstrate that in the Bole sample(sample 19),the total of ten years of simulation values is 386 g C/m2, the measured value is 422.73 g C/m2 in 2006, the ratio is 91.31%; in the Jinghe sample(sample 23), the total of ten years of simulation values is 400.60 g C/m2,the measured value is 468 g C/m2 in 2006, the ratio is 85.60%. Overall, the ratio between the simulated value and the measured value was greater than 85%, which suggests the model is effective. According to the output result of the model shows that: The carbon NPP dynamic pattern in Ebinur lake wetland ecosystem shows a slowly increasing trend in recent 55 years; the trend of two sample areas in annual biome net production of the Ebinur Lake Wetland as follows: there was a decreasing trend in Bole, While generally showed an increasing trend in Jinghe; in the recent 55 years, the pricipitation and evaporation of Ebinur Lake wetland ecosystem showed a growth trend.