蜀南竹海毛竹林土壤物理性质空间异质性

土壤空间异质性是土壤的重要综合属性,对土壤的结构与功能以及植被的空间格局有重要影响。以蜀南竹海核心区毛竹林土壤为研究对象,采用1∶10000地形图为工作底图,按公里网格布点,应用地统计学方法,分析了土壤物理性质的空间异质性,旨在为研究区毛竹林的可持续经营提供基础数据和理论参考。结果表明:除土壤最大持水量和最小持水量外,研究区土壤粘粒、容重、非毛管孔隙度、毛管孔隙度和毛管持水量等5个土壤物理性质空间变异性明显,其半变异函数用指数、高斯和球状模型拟合,变程范围在1252.3—11887.1 m,块金值和基台值比值范围为0.03%—52.07%,表明各物理性质有不同程度的空间自相关性;土壤持水特性有较大的块金值,说明存在小尺度的空间异质性;普通克里格插值及物理性质空间分布图表明,土壤物理性质在空间分布上具有斑块性,在不同土层深度的空间分布有一致性。人为干扰是影响研究区土壤物理性质空间分布格局的一个主要原因。减少人为干扰,优化林分结构,维护与提高毛竹林生产力。

Spatial heterogeneity of soil physical properties in Phyllostachys heterocycla cv pubescens forest, South Sichuan Bamboo Sea

Soil spatial heterogeneity is an important property of soil integration and has significant effects on the spatial patterns related to the structure, function, and vegetation of soil. The object of the study reported in this paper was the soil in a Phyllostachys heterocycla cv. Pubescens forest, a core scenic spot within the South Sichuan Bamboo Sea. According to geo-statistical methods, a topographic map at a scale of 1:10000 was used to set the intersections of 1 km-square mesh points as observation points. At each observation point, the spatial heterogeneity of soil physical factors was analyzed, with the aim of supplying the basic data and theoretical reference for the sustainable management of the bamboo forest in the study area. The results showed that except for the maximum and the minimum water holding capacity of the soil, the five physical factors measured (soil clay particles, bulk density, non-capillary porosity, capillary porosity, and capillary water holding capacity) in the study area exhibited obvious spatial heterogeneity. Indexes, along with Gaussian and Spherical models, were used to fit the semi-variant function of the measured parameters. The major range of these indexes was between 1252.3 and 11887.1 m. The ratio of Nugget and Still, ranging from 0.03% to 52.07%, suggested that the physical factors had different levels of spatial autocorrelation. The soil water retention had a higher Nugget ratio, explaining a small-scale spatial heterogeneity existing in it. The Ordinary Kriging, and the spatial distribution map of physical properties showed that the soil physical properties had a plaque-type spatial distribution. Among the different layers, the spatial distribution was consistent. Human disturbance was the major factor affecting the space distribution pattern of the soil physical properties. To maintain and improve the productivity of the bamboo forest, human disturbance must be reduced and the stand structure optimized.