杭州湾南岸土壤有机碳空间异质性研究

应用地统计学与地理信息系统相结合的方法,研究了杭州湾南岸慈溪市域内不同土层(0～20、20～40、40～60、60～80、80～100、0～100 cm)的土壤有机碳含量空间变异特征。结果表明:研究区各土层土壤有机碳平均含量变化范围为3.49～7.95 g kg-1,变异系数介于54.51%～67.34%之间,属中等程度变异;地统计分析得出块金效应变化范围为0.141～0.372,表现为较强空间自相关性;自表层至底层最优半方差模型依次为高斯、指数、指数、高斯和球状模型;Kriging插值结果显示各土层土壤有机碳含量自滩涂向内陆呈递增趋势,其中0～20 cm土层土壤有机碳含量呈平行于海岸线的带状分布;土壤有机碳含量随剖面深度增加呈递减规律;不同土地利用方式和不同围垦时期均增加了土壤有机碳的空间变异性。从研究结果看,慈溪市土壤有机碳空间异质性主要由结构性因素引起,研究结果可为了解杭州湾南岸土壤有机碳分布特征提供参考。

Spatial heterogeneity of soil organic carbon on the south coast of Hangzhou Bay

The Geostatistics and Geographical Information System(GIS) were employed to study the space variability characteristics of soil organic carbon of different soil layers (0 ~ 20cm, 20 ~ 40cm, 40 ~ 60cm, 60 ~ 80cm, 80 ~ 100cm) in Cixi, the south region of Hangzhou Bay. The results indicated that: the soil organic carbon average content of the different soil layer ranged from 3.49 to 7.95g/kg in the study area, the variation coefficients ranged from 59.90% to 67.34%, showing a moderate degree variation; geostatistical analysis indicated that the value of nugget effect varied from 0.628 to 0.859, presenting weak spatial correlation, and the optimal semi-variance model were Gaussian, exponential, exponential, Gaussian and spherical respectively from the surface layer down to bottom layer; the content changes of soil organic carbon showed an increasing trend from the beach to the inland and the soil organic carbon distribution