黔中喀斯特山区村域稻田土壤理化特性的空间变异特征及空间自相关性

以贵州省安顺市西秀区旧州镇文星村为研究区域,采用地统计学方法,研究了黔中喀斯特山区土壤容重、总孔隙度、毛管持水量、毛管孔隙度、通气孔隙度等物理特性与土壤pH、有机质、速效养分(S、Si、N、P、K、Fe、Zn、Cu、Mn)、全量养分(N、P、K)、交换性盐(Ca、Mg)及阳离子交换量等化学特性的空间变异特征及自相关性。在土壤各特征值中,pH、毛管孔隙度变异系数分别为4.59%、8.28%、9.83%,为弱变异;其他变异系数在10%-100%之间,为中等程度变异。半方差分析表明,土壤毛管持水量、通气孔隙度、毛管孔隙度、速效养分(S、Si、Cu、Mn)、全量养分(N、P、K)、交换性盐(Ca、Mg)及阳离子交换量的C₀/(C₀+C)<25%,表现为强烈的空间自相关性;容重、pH、速效养分(N、P、K、Fe、Zn)及有机质的C₀/(C₀+C)在25%-75%之间,表现为中等空间自相关性,而Moran''s I指数分析表明,除毛管孔隙度、有效S、速效P及有效Mn的空间自相关性较弱外,其他均呈正的显著空间自相关性。根据克里金插值图,在研究区域内土壤毛管孔隙度及毛管持水量与pH、速效养分(S、Si、Zn、Cu、)全P、全N、有机质、交换性Ca、Mg及阳离子交换量在东北方向和西北角分布较低,在西南角方向土壤容重及通气孔隙度分布较低,而pH、速效K、有效Cu、全P、全K、有机质、阳离子交换量分布较高,且速效养分(N、K、S、Cu)、全P、有机质的含量及阳离子交换量均存在从西南向东北方向递减的趋势。

Spatial variability of soil physiochemical properties and their autocorrelations at village-region in karst mountainous area, Guizhou Province

Using the geo-statistical method, we investigated spatial variability and autocorrelation of 5 soil physical properties (including soil bulk density, total porosity, capillary water holding capacity, capillary porosity, aeration porosity), 17 nutrient elements (including pH, available N,S, Si, P, K, Cu, Zn, Fe, Mn, total K, P, N, organic matter, exchangeable Ca, Mg and CEC) in Wenxing village, Anshun city in Guizhou province. First, our results showed that the Cv of soil pH and capillary porosity were lower than 10%, indicating their weak variation. In contrast, others had a variation coefficient between 10% -100% for moderate variation. Next, our semi-variogram analysis showed that the ratios of nugget to sill for soil capillary water holding capacity, aeration were lower than 25%, demonstrating their strong spatial auocorrelations. Contrarily, soil bulk that the capillary porosity, available P, S, Mn have a weak spatial correlation, the others displayed positive significant spatial autocorrelation. Finally, from the kriging interpolation maps at the study area, soil total porosity, capillary porosity, available S, Si, Cu, Mn, total N, P, K, exchangeable Ca, Mg and CEC porosity, capillary porosity, capillary water holding capacity, and pH, available S, Si, Zn, Cu, total P, N, organic matter, exchangeable Ca, Mg and CEC were lower in northeast and northwest area, whereas the soil bulk density, aeration porosity were lower in southwest area, and pH, available K, Cu, total P, K, organic matter, CEC were higher in the southwest direction. Furthermore, the contents of available nutrients (N, K, S, Cu), total P and organic matter and CEC displayed a decreasing trend from southwest to northeast area.