干旱荒漠区煤矸石山覆土区土壤水分物理性质的空间异质性

基于网格取样(20 m×20 m),采用经典统计学和地统计学相结合的方法,研究了干旱荒漠区煤矸石山表层(0~5 cm)土壤水分物理性质的空间异质性和分布格局。结果表明:研究区土壤容重、毛管孔隙度、毛管最大持水量、总孔隙度、饱和含水量表现为弱变异,土壤含水率表现为中等变异。除土壤容重的最佳拟合模型为高斯模型外,其余指标的最佳拟合模型均为指数模型;土壤容重和含水率的块基比C₀/(C₀+C)]较小,空间自相关性强烈;土壤毛管孔隙度、毛管最大持水量、总孔隙度和土壤饱和含水量则表现为中等的空间自相关性;土壤容重与毛管孔隙度、毛管最大持水量、总孔隙度、饱和含水量呈极显著负相关,土壤含水率与其余指标没有显著的相关关系;土壤毛管孔隙度、毛管最大持水量、总孔隙度及饱和含水量两两之间呈极显著正相关关系;Kringing等值线图表明,土壤毛管孔隙度、毛管最大持水量、总孔隙度和饱和含水量分布类似,高值集中在坡中部及下部左侧,土壤容重则与之相反,土壤含水率的大小主要受坡位的影响,由坡上向坡下增大。建议干旱荒漠区煤矸石山覆土区在人工植被恢复时应采取整地措施,疏松根区土壤;在植被恢复初期,应适当提高坡上部的灌水量,以改善煤矸石山覆土区土壤水分状况,为植被恢复营造均一、良好的土壤水分物理条件。

Spatial heterogeneity of soil water physical properties in coal gangue pile in arid desert area

Based on grid sample method (20 m×20 m), spatial heterogeneity and distribution of soil water physical properties from 0 to 5 cm of the coal gangue pile in arid desert area were explored by using classical statistics and geostatistics methods. The results showed that the variation of soil bulk density, capillary porosity, capillary maximum moisture capacity, total porosity and saturated moisture contents were weak, while water content showed a moderate variation. The best fitting model of soil bulk density was Gaussian model, and exponential model was the best fitting model for other indices. The C₀/(C₀+C) values of soil bulk density and water content were low and had strong spatial autocorrelation. The capillary porosity, capillary maximum moisture capacity, total porosity and soil saturated moisture showed moderate spatial autocorrelation. Soil bulk density was negatively correlated with capillary porosity, capillary maximum moisture capacity, total porosity and water content, whereas there was no significant correlation between soil moisture content and other indices. Soil capillary porosity, capillary maximum moisture capacity, total porosity, and saturated water content showed a significant synergistic effect between each other. On Kriging contour maps, capillary porosity, capillary maximum moisture capacity, total porosity and saturated moisture had a similar spatial pattern, with high values on the middle and the left side of the lower slope, whereas soil bulk density showed an opposite pattern. Soil water content was mainly affected by the slope position and increased from the upper slope to the lower slope. Our results suggested that land preparation measures should be taken to loosen the soil in root area over the coal gangue pile in arid desert area during vegetation restoration. Moreover, irrigation amount should be properly increased on the upper slope during the initial stage of vegetation restoration, which could improve soil moisture status in the overlying soil area of coal gangue and create uniform and suitable soil water physical conditions for vegetation restoration.