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基于区域化变量理论和地理信息系统的空间分析功能,应用地统计学的半变异函数定量分析了亚热带红壤丘陵区典型景观单元土壤养分的空间异质性特征。结果表明,土壤有机碳和全磷的理论模型为球状模型、全氮为高斯模型、土壤pH为指数模型。在60m步长间隔尺度下,土壤有机碳、全氮和pH有强烈的空间相关性,土壤全磷空间相关性为中等程度。4种土壤养分的空间自相关范围具有明显的差异,有机碳的有效变程最大(为261m),全氮(208m)和pH(156m)次之,全磷的有效变程最小(133m)。其空间自相关范围的差异由本身的养分、土地利用格局、地形和人为管理措施等因素所决定。在GIS支持下,采用Kriging插值方法,分析景观单元内土壤养分的空间分布格局看出,土壤有机碳和全氮含量呈现出明显的条带状和斑块状的梯度变化,并表现出极为相似的空间分布格局;土壤全磷的空间分布随机性强,斑块变得更加琐碎并呈现镶嵌的“星空”状分布;土壤pH的空间分布格局处于其三者之间,没有表现出明显的条带状分布。总体上说,基于整个景观尺度的4种土壤养分的半方差拟合效果优于不同土地利用类型的拟合效果。
Based on the theory of regionalized variables and spatial analysis of geographic information system, the semi-variogram of geostatistics was used to quantitatively analyze the spatial heterogeneity of soil nutrients in typical landscape units in subtropical red soil hilly region. The results show that the theoretical models of soil organic carbon and total phosphorus are spherical model, total nitrogen is Gaussian model, soil pH is exponential model. At 60m intervals, soil organic carbon, total nitrogen and pH had a strong spatial correlation, and the spatial correlation of soil total phosphorus was moderate. The spatial autocorrelation range of soil nutrients has obvious difference. The effective range of organic carbon is the largest (261m), followed by total nitrogen (208m) and pH (156m), and the effective range of total phosphorus is the smallest (133m). The spatial autocorrelation differences are determined by factors such as nutrient, land use pattern, topography and man-made management measures. Kriging interpolation method was used to analyze the spatial distribution pattern of soil nutrients in landscape units under the support of GIS. The results showed that soil organic carbon and total nitrogen content showed obvious bands and patchy gradient changes, and showed very similar The distribution pattern of total phosphorus in soil was random and strong, and the patches became more trivial and inlaid “star-like” distribution. The spatial distribution pattern of soil pH was in the middle of them, and no obvious bands Belt distribution. Generally speaking, the semi-variance fitting effect of four kinds of soil nutrients based on the entire landscape scale is better than the fitting effect of different land use types.