关键词: 土壤无机碳, 无机碳储量, 荒漠生态系统, 土壤类型

Abstract:

Soil inorganic carbon (SIC) is a significant component of arid region carbon stock. Distribution characteristics of SIC and magnitude of SIC stock are crucial premise for comprehending soil carbon cycle in desert ecosystem of arid regions. Based on the field investigations and laboratory analyses, we researched the SIC distributions and dissimilarities of different soil types, estimated SIC storage of research area and examined correlation of SIC with SOC and soil physico-chemical factors, discussions and comparative analyses were also made on aforementioned contents. The results showed that: Aaverage SIC content on the whole profile of four soil types range from 53.06 g·kg-1 to 79.90 g·kg-1; There were significant differences among various types (p<0.05). The order of SIC content on layers above 50 cm depth was grey-brown desert soil>saline and alkaline soil>hydromorphic soil>Aeolian sandy soil, but SIC content of saline and alkaline soil and hydromorphic soil increased gradually and exceeded grey-brown desert soil on layers below 50 cm depth. On vertical distribution, SIC content generally display a trend that first increasing and then decreasing as the soil depth increases (at 10 cm depth level). Profile distribution of SIC was relatively homogeneous except for that of grey-brown desert soil. Total SIC storage in study area was estimated to be 234.50 Tg to the depth investigated to 120 cm, and average SIC density was calculated to be 9.37 kg·m-2. SIC had positive correlation with soil organic carbon and water content, and which inclined to increase with soil depth slightly, as for soil bulk density and pH of surface layer, the correlation was negative and weak relatively.

Key words: soil inorganic carbon, inorganic carbon storage, desert ecosystem, soil type