岩溶坡地土壤空间异质性的表述与调查方法-以贵州清镇市王家寨坡地为例

EXPRESSION AND INVESTIGATION METHODS OF SOIL SPATIAL HETEROGENEITY IN KARST SLOPE——AS EXEMPLIFIED BY WANGJIAZHAI SLOPE IN QINGZHEN CITY,GUIZHOU PROVINCE

讨论了岩溶坡地土壤空间异质性的表述与调查方法，选取了地表石质土地面积比例及空间分布和土壤厚度及空间分布两个方面作为土壤空间异质性的表述内容，引入了地块破碎度、离散度、变异函数等指标；以王家寨为例，研究发现岩溶坡地土石比、破碎度、离散度、土壤厚度等指标从坡顶到坡下逐渐增大；石质地块破碎度在微观地块上表现为值越大地块越完整，是否与研究尺度有关还需要进一步论证；土壤厚度变异系数基本在1-1.5之间，与土壤厚度变程和土壤平均厚度有关；最后用土壤侵蚀的原理解释了岩溶坡地土壤空间异质性。

To express effectively the soil spatial heterogeneity in a karst zone, we chosed the proportion of rock area on overland and the rock area＇s spatial distribution and the depth of soil and its spatial distribution as research facts. We made a wooden block to extract information on overland, which includes spatial distribution of rock plague and the rock plague＇s area. The depth of soil was measured by a steel driller which was calibrated scale per centimeter and then the depth information was expressed by isobathic diagram. The fragmentation and dispersion were utilized to quantitatively describe the proportion of rock area on over-land and the rock area＇s spatial distribution and the variable function was used in soil depth variety. Then, we sampled the Wangiiazhai slope and found that the indices including the proportion of soil area, fragmentation, dispersion and mean soil depth were enlarged from upper slope to bottom slope. In theory the value of rock area fragmentation is bigger, meaning the area is more cracked. But it was opposite in our study. Nevertheless, more experiments were needed to testify whether the result is reverse between microscopic landform and macroscopic landform. The values of variable index range from 1 to 1.5,which is decided by the extent of soil depth and the mean soil depth. Finally, we tried to explain the soil spatial heterogeneity by soil erosion principle.