为探讨高地质背景区土壤Cd含量的空间分异特征及变化规律,从贵阳市喀斯特地区的表土中采集了14421个表土样品。全球莫兰I指数,冷热点分析,半方差函数,利用Kriging插值方法揭示了土壤Cd含量的空间结构和分布规律。通过方差分析和地理检测器分析了环境因子对土壤Cd含量的影响及其主控因素。结果表明:①贵阳喀斯特表层土壤Cd含量在0.03~1.36mg·kg-1之间,平均为0.440mg·kg-1,是贵州土壤Cd背景值和我国土壤Cd背景值的1.77倍和5.95倍。分别。土壤Cd超标率为30%,是中国土壤Cd含量7%的4.29倍。②土壤Cd含量呈显著的空间正相关,显示出全球空间的聚集趋势,而在当地,东北和西南是热点地区,北方是一个寒冷的地方。土壤Cd含量的熔核系数为10.37%,说明土壤Cd主要受结构性因素的影响。③在空间分布方面,土壤Cd表现出不同的积累趋势。在一些巨大的土壤中,如西丰县,修文县,清镇市,花溪区,南明区,土壤ω(Cd)小于0.3mg·kg-1。白云区土壤ω(Cd)在0.3~0.6mg·kg-1之间,武当区,观山湖区,整个云岩地区都在这个范围内。0.6~0.9mg·kg-1的土壤ω(Cd)集中在清镇市西南部,在花溪区的南部,开阳县北部,而土壤ω(Cd)在0.9~1.2mg·kg-1之间,主要集中在清镇市西南部。土壤Cd含量极值(1.2mg·kg-1)主要分布在开阳县,修文县,清镇市,和花溪区。④方差分析和地质检测结果表明,不同环境因子对土壤Cd的空间分异有显著影响,但它们对土壤Cd含量的解释力不同:地层(0.1765)>土壤类型(0.0260)>有机质(0.0251)>海拔(0.0105)>母岩(0.0073)>土地利用(0.0064)>pH(0.0013),地层与任意环境因素之间的相互作用最大。因此,地层是影响土壤Cd含量空间分异的主要因子。
In order to explore the spatial differentiation characteristics and variation law of soil Cd content in a high geological background area, 14 421 topsoil samples were collected from topsoil in the karst area of Guiyang City. Global Moran\'s I index, cold hot spot analysis, semi-variance function, and Kriging interpolation were used to reveal the spatial structure and distribution law of soil Cd content. The influence of environmental factors on soil Cd content and its main controlling factors were analyzed through analysis of variance and geographic detector. The results showed that: ① The Cd content of karst surface soil in Guiyang varied from 0.03 to 1.36 mg·kg-1, with an average of 0.440 mg·kg-1, which was 1.77 times and 5.95 times the Guizhou soil Cd background value and Chinese soil Cd background value, respectively. The over-standard rate of soil Cd was 30%, which was 4.29 times that of 7% of soil Cd in China. ② There was a significant spatial positive correlation of soil Cd content, showing an aggregation trend in the global space, whereas in the local region, the northeast and southwest were hot spots, and the north was a cold spot. The nugget coefficient of soil Cd content was 10.37%, indicating that soil Cd was mainly affected by structural factors. ③ In terms of spatial distribution, soil Cd showed different accumulation trends. In some massive soils, such as Xifeng County, Xiuwen County, Qingzhen City, Huaxi District, and Nanming District, the soil ω(Cd)was less than 0.3 mg·kg-1. The soil ω(Cd)was between 0.3 and 0.6 mg·kg-1,and soil Cd in Baiyun District, Wudang District, Guanshan Lake area, and Yunyan area as a whole lied within this range. The soil ω(Cd)between 0.6 and 0.9 mg·kg-1 was concentrated in the southwest of Qingzhen City, the south of Huaxi District, and the north of Kaiyang County, whereas soil ω(Cd) between 0.9 and 1.2 mg·kg-1 was mainly concentrated in the southwest of Qingzhen City. The extreme value of soil Cd content ( > 1.2 mg·kg-1) was mostly distributed in Kaiyang County, Xiuwen County, Qingzhen City, and Huaxi District. ④ The results of analysis of variance and geo-detector showed that different environmental factors had significant effects on the spatial differentiation of soil Cd, but their explanatory power on soil Cd content varied: stratum (0.176 5) > soil type (0.026 0) > organic matter (0.025 1) > altitude (0.010 5) > parent rock (0.007 3) > land use (0.006 4) > pH (0.001 3), and the interaction between stratum and arbitrary environmental factors was the greatest. Therefore, stratum was the main factor affecting the spatial differentiation of soil Cd content.