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城市非渗透面(Impervious Surface Areas,ISA)的覆盖,强烈地改变了区域土壤理化性状,从而在不同尺度上影响着生态系统碳循环。ISA下土壤样品获得的困难性致使对ISA所封存的土壤有机碳(Soil Organic Carbon beneath ISA,SOCISA)及其分布特征的认识极为缺乏。为揭示ISA下土壤理化特征,本文收集天山北坡城市群在建工程ISA下27个100 cm深土壤样品,同时采集对应ISA点邻近的渗透面(Pervious Surface Areas,PSA)样品作对比分析。利用Landsat 8图像提取了研究区ISA与PSA面积,并结合实测值估算SOC储量。研究发现:1干旱区城市100 cm深土壤剖面平均SOCISA=5.74±0.39 kg C·m-2,显著低于其邻近PSA下的SOC;ISA下土壤容重(Bulk Density,BD)BDISA=1.58±0.02 g·cm-3,显著高于其邻近BDPSA约5%(p<0.01)。2两种地表下SOC和BD均随着深度加深而降低,通过与土层深度的线性拟合,SOCISA和BDISA具有明显降低趋势,PSA下SOC和BD并无显著规律;深层土壤(60~100 cm)SOCPSA显著高于SOCISA(p<0.05),两者间并无稳定的比例关系。3天山北坡城市群SOCISA为总城市土壤碳库的68%,单个城市SOCISA比例50%以上,SOCISA构成干旱区城市土壤碳库的主体。本文不仅加深了对城市ISA下土壤理化性状的了解,而且对评估城市乃至全球生态系统碳循环及碳评估具有重要意义。
The coverage of urban Impervious Surface Areas (ISA) has strongly changed the soil physical and chemical properties of the area, affecting the ecosystem carbon cycle at different scales. The difficulty of obtaining soil samples under ISA has led to a lack of understanding of the Soil Organic Carbon beneath ISA (ISA) and its distributional characteristics. In order to reveal the soil physical and chemical characteristics under ISA, we collected 27 100 cm deep soil samples under the ISA of the Tianshan northern slope urban agglomeration and collected Pervious Surface Areas (PSA) samples corresponding to ISA points for comparative analysis. The Landsat 8 images were used to extract the ISA and PSA areas of the study area, and the SOC reserves were estimated based on the measured values. The results showed that: 1 The mean SOCISA of soil profile at a depth of 100 cm in arid area was 5.74 ± 0.39 kg C · m-2, which was significantly lower than that of its adjacent PSA. The BDISA of the soil bulk density at ISA was 1.58 ± 0.02 g · cm-3, significantly higher than its adjacent BDPSA about 5% (p <0.01). SOC and BDISA both decreased significantly with the depth deepening. SOCISA and BDISA decreased significantly with the linear fit to soil depth, and there was no significant rule for SOC and BD in PSA. Deep soil (60-100 cm) SOCPSA was significantly higher than SOCISA (p <0.05), there is no stable ratio between the two. 3 The SOCISA of the Tianshan northern slope urban agglomeration is 68% of the total urban soil carbon pool, and SOCISA in a single urban area is more than 50%. SOCISA constitutes the main body of urban soil carbon pool in arid regions. This paper not only deepens the understanding of soil physical and chemical properties under urban ISA, but also has important significance in assessing the carbon cycle and carbon assessment of urban and even global ecosystems.