广东省典型赤红壤区耕层土壤养分的空间变异

目的]探讨我国典型赤红壤区——广州市增城区耕层土壤有机质、全氮、有效磷和速效钾含量的空间变异规律,为赤红壤区耕层种植的平衡施肥、水土保持和环境保护提供依据。方法]利用地统计学方法和地理信息系统技术。结果]研究区耕层土壤有效磷的含量较高,速效钾的变异系数最大(107.78%),有机质的变异系数最小(32.51%),变异系数由大到小依次为:速效钾有效磷全氮有机质;有机质、全氮具有强烈的各向同性空间自相关性,有效磷与速效钾有着较明显的各向异性空间自相关性;有机质、全氮有着相似的空间分布规律,含量呈东南部高西北低的趋势,有效磷含量处于中上偏高水平,空间分布从北向南呈逐步增多趋势,速效钾空间分布相对比较复杂,各个养分级别都有一定量的分布,总体由北到南逐渐增多。结论]在一定空间范围内,耕层土壤有机质、全氮、有效磷和速效钾具有不同强度的空间相关性,且选取合适的方向性半方差函数模型能更好地拟合其空间变异情况。

Spatial Variability of Topsoil Nutrients in Typical Lateritic Red Soil Areas of Guangdong Province

Objective]The spatial variabilities and spatial distribution patterns of topsoil organic matter(SOM), total nitrogen(TN), available phosphorus(P) and available potassium(K) in Zengchen District of Guangzhou City were analyzed in order to provide some hints on how to improve fertilizer use efficiency and to prevent water and soil pollution in analogous area with lateritic red soil.Method] Geostatistic and GIS methods are used in this study.Result] The results showed that P content is high overall in the district. The maximum coefficient of spatial variation comes with K, up to 107.78%; whereas the minimum nutrient is SOM, about 32.51%. Coefficients of variation have a rank of K >P >TN >SOM. SOM and total N have distinct spatially isotropy auto-correlations; On the contrary, available P and K behave obvious anisotropy auto-correlations. The contents of SOM and TN are higher in the southeast and northwest, but lower in the central; P content of the district increases from north to south gradually. A general increase from north to south displays for the spatial distribution of K content, but it seems to be more complicated.Conclusion] If observed within a certain space, topsoil SOM, TN, P and K have their different spatial correlations, upon which, a suitable directional semi-variance function model need to be find out to describe their spatial variabilities better.