The Storage Of Urban Surface Soil Organic Carbon And Its Spatial Distribution In Xi’an

With the accelerated urbanization development, the role of urban soil carbon pool comparing with all soil carbon storages along urban area growing. It can provide an important scientific evidence to research urban soil carbon stocks for understanding environmental effects by urbanization. In this paper, the range within the Xi’an beltway as objective, 306 soil samples were collected depending on the difference of land use/function, the soil density was simultaneous determined. The soil organic carbon was measured by the company’s German Elementar Vario EL III elemental analyzer. The results obtained at:(1) The soil carbon content of city area was 0.88-27.18 g/kg with mean 5.59±0.12 g/kg, median and standard deviation were 4.35 and 4.97, and skewness coefficient of performance of 1.98 was right skewed, kurtosis of 5.03 showed a steep sharp peak. The soil carbon content was different for every land use or land function area, and the order was Lounge>Transportation District>Industrial Zone>Residential/Re-gion>cultural and educational area> commercial district. Overall, soil carbon content was lower compared with that of other cities.(2) Soil carbon density was affected by the carbon content and soil density. The urban topsoil carbon density was 0.22-7.11 kg/m2 average with 1.47 kg/m2. The topsoil carbon density of different functional areas showed significant differences, the Lounge highest up to 1.99 kg/m2, the industrial areas lowest to 1.00 kg/m2.(3) The carbon density in Xi’an city area had a spatial changes, in the central part of the city has a high carbon density, and the carbon density tends to decrease from the center to the edges. Soil carbon density was significantly higher in the southern and the northern region than that in the western and eastern of Xi’an city.(4) The surface soil total carbon storage is 6.21 × 105 t in inner beltway of Xi’an city with soil carbon 1.35 × 103 t per square kilometers. The area within the Second Ring as the city center, surface soil carbon storages is 1.21 × 105 t with 1.60 × 103 t. per square kilometers.The pool of city relates soil carbon stocks and vegetation carbon. But, this paper was only soil carbon to part of the overall. The comprehensive study through urban green space system is a direction of urban carbon pool, and the urban land use also changes carbon storage. Thus, these areas are also worthy of further study.