【作者】 刘鑫；

【导师】 毕华兴；

【作者基本信息】 北京林业大学 ， 水土保持与荒漠化防治， 2007， 硕士

【摘要】 本论文旨在对实验区内不同采样尺度、不同植被类型、不同地形因子的样地小区，利用统计学、地统计学、GIS等研究方，分析坡面上0～30cm及30～60cm土层土壤水分的变异规律，其中主要分为四个研究方向：1．在小尺度的坡面上研究不同采样幅度及采样间距对土壤水分变异规律的影响。2．研究小尺度上土壤水分空间变异沿坡长方向的各向同性问题，并得出较好的套合结构模型。研究中尺度上土壤水分空间变异的各项异性问题，并得出综合的套合结构模型。3、研究不同植被类型、不同小区布设方向(即坡向)、不同林分密度对土壤水分变异规律的影响。共选择14个取样小区。4、在一中尺度典型梁峁坡上，研究地形因子对土壤水分分布规律的影响，找出土壤水分与地形因子的相互关系。研究发现：尺度性研究：随着采样幅度尺度的增大，土壤水分变异的特征参数如变异系数、相关距离和Moran的I相关指数都不同程度地增大；当采样间距增大时，变异系数和Moran的I相关指数没有变化，而相关距离却减小。在小区尺度上，400～600 m~2的面积范围误差值小，可以表示真实变异情况。套合结构研究：在小区尺度上相同采样数目，不同采样体积及间距的套合小区内土壤含水量的空间变异结构函数差别较大。用套合结构能较好的放映其空间变异规律。在田间尺度上在不同的方向上，土壤水分的空间变异其块金值和基台值有一定的差异，具有典型的带状异向性特征。其在垂直方向与水平方向上具有最强烈的空间带状结构。不同植被类型研究：不同植被类型对土壤水分有较大的影响，但这种影响随着土层和季节的变化而变化并没有一定的规律。总的来看在10月份，其异质性情况是刺槐纯林＞退耕地＞天然林＞油松刺槐混交林＞油松纯林＞农地＞刺槐侧柏混交林＞侧柏纯林＞草地，在4月份其异质性情况是油松纯林＞天然林＞油松刺槐混交林＞刺槐纯林＞农地＞侧柏纯林＞草地＞刺槐侧柏混交林。不同布设方向：不同的坡向即小区布设位置对土壤水分的空间变异情况产生影响，并且这种影响呈聚类的变化规律而且有着季节的变化。10月份，变异程度是东＞南＞西。4月份，总的变异情况时西＞东＞南。不同林分密度：不同林分密度对土壤水分变异情况有着显著的影响。随着林分密度的增大，其土壤水分的变异程度呈曲线变化规律，在10月份，随着林分密度的增加而呈现先减少后增加的趋势。在4月份随着密度的增大在表层有先增大后减少的趋势，而在底层有着先减少再增大而后减少的趋势。地形因子：地形因子对浅层土壤水分有着重要的影响，对地形因子与土壤水分的属性数据库进行主成分分析得出：在0～30cm土层坡向为主成分，高程的影响程度次之，坡度最小；在30～60cm土层，坡度为主成分，高程的影响程度次之，坡向最小。通过聚类分析得出：坡向按顺时针方向分282.5°～112.5°，112.5°～282.5°两类，与传统的阴、阳坡划分基本相吻合。坡度划分为：5°～20°和20°～35°二类。更多还原

【Abstract】 In this paper, the different experimental district is type include different scale , different vegetation and different topographic factor were choose and then the rule of spatial and temporal heterogeneity of soil moisture under different soil layers(0～30cm and 30～60cm ) were found by using the Statistics, Geostatistics and GIS means. There have four aspects that include 1.the impact of spatial and temporal heterogeneity of soil moisture under different sampling extent and spacing scales 2. Analysis question of isotropy in the small scale slope and the anisotropic in moderate scale and then acquired their nested model. 3. Study on the impact of different vegetation, different slope and different density forest in 14 experimental districts. 4. Found out the relation of topographic factor and soil moisture in a typical hill which is the moderate scale. The result as that:1 Scale: The results showed that all the indices including coefficient of variation, correlation length and Moran’I index measured increased with various degrees with increasing extent. However, spacing did not affect coefficient of variation and Moran’I index, while correlation length decreased with the increase of spacing.2.Nested model: In the Plot-scale, there have a significant different of spatial heterogeneity between the different scale district, so the nested model would be better showed the condition of spatial heterogeneity; in the Field-scale, because of there have different nugget and sill among the different direction, the spatial heterogeneity of soil moisture have a strap anisotropic and while it have a strong strap construction in the uprightness and level direction.3. Different vegetation: It has obvious impact to the spatial distribution and heterogeneity of the soil moisture but this impacting isn’t rule follow the change of soil layers and season. In the main, in the Oct 2005, the heterogeneity extent is silver chain >fade farmland >nature forest >pine & silver >pine>farmland >arborvitae & silver >arborvitae>grassland; in the Apr 2004, it is pine> nature forest>pine & silver>silver chain>farmland> arborvitae >grassland>arborvitae & silver.Different aspect: It has obvious impact to the spatial distribution and heterogeneity of the soil moisture and this impacting have a clustering and seasonal change. In the Oct 2005, the heterogeneity extent is east>south >west; in the Apr 2004, it is west>east >south.Different density forest: It has obvious impact to the spatial distribution and heterogeneity of the soil moisture. Following the increase of density, it has showed a curve trend. In the Oct 2005, it firstly decrease and the increase along with the density enhance. In the Apr 2004, it firstly increase and then decrease in the 0～30cm,and firstly decrease and then increase in the 30～60cm. 4.Topographic factor: Results show that in the 0～30cm soil layer, the topographic factors were in the order of aspect >elevation> slope in effect on soil moisture, while in the 30～60cm soil layer, the sequence is slope>elevation> aspect. The cluster analysis of aspects and slopes indicated that aspects could be sorted into two categories: 292.5°～360° (0°) ～ 112.5° (shady slope) and 112.5° ～292.5° (sunny slope), and so could slopes, 5° ～ 20° and 20° ～ 35° according to their effects on soil moisture.更多还原