贵州喀斯特峰丛洼地石漠化区土壤物理特征时空分异

喀斯特峰丛洼地在全国8个石漠化治理区中面积（310万hm2）居第二位，贵州是全国石漠化最严重的地区。喀斯特生境的高度异质性、土被不连续性，导致土壤物理特性的差异，使持水保水能力有较大差异。为了弄清喀斯特峰丛地石漠化区土壤物理特征时空分异，利用环刀法对贵州喀斯特峰丛洼地石漠化实验区不同季节、不同地貌部位的土壤取样，用SPSS19.0数学统计方法对样品进行统计分析，结果表明:①土壤物理特征存在较大的时空分异，除了少部分为弱变异外，其它均表现为中等变异程度，这与生境类型复杂多样、生境高度异质性有关。②不同坡度土壤物理特征变化不显著，但土壤物理特征在不同地貌部位（上、中、下坡）随季节（春、夏、秋、冬）变化而变化。③不同植被类型下，除了非毛管孔隙度外，土壤自然含水量等物理特征变化极显著。以灌木林、人工林（经果林）分布区域土壤较为疏松、透气性好，而以针叶林或荒草地分布区，土壤粘重，透气性相对较差。 

Spatiotemporal variations of soil physical characteristics in rocky desertification areas of Guizhou karst-cluster depression

The karst peak cluster depression is ranked as the second place of eight rocky desertification control areas in our country, which is of 3.1 million hm2. Guizhou province is the region with most serious rocky desertification nationwide. In combination of field investigation with laboratory analysis and using SPSS19.0 statistics method, this work focused on the change of soil physical characteristics in different seasons and different landform parts of this region. The results show that，(1) There is big spatial and temporal differentiations. Besides a few loci with weak variation, others are characterized by medium degrees of variation related to complex and varied habitat types and heterogeneity of habitat height. (2) Soil physical characteristics do not change significantly with slopes, while showing prominent variations in different landforms (upper, middle and lower slopes) and different seasons (spring, summer, autumn, winter). (3) For different vegetation types, in addition to the non-capillary porosity, soil physical characteristics such as natural water content change significantly. In the areas with shrubbery and secondary woodland (economic fruit woods), the soil is relatively loose and the permeability is good, while in the coniferous forests or grassland areas, the soil is viscous and heavy, and the permeability is relatively poor.