黄土高原丘陵沟壑小流域土壤水分垂直分布变异特征及影响因子  

Spatial variability of soil moisture vertical distribution and related affecting factors in hilly and gully watershed region of Loess Plateau

作　　者：白天路[1] 杨勤科[1] 申佳[2] 

机构地区：[1]西北大学城市与资源学系,西安710069 [2]河南省安阳市国土资源调查规化与测绘院,河南安阳455000

出　　处：《生态学杂志》2009年第12期2508-2514,共7页Chinese Journal of Ecology

基　　金：国家自然科学基金资助项目(40971173)

摘　　要：以地统计学的半变异函数为分析工具,分析了黄土高原丘陵沟壑区小流域土壤水分在垂直方向的空间变异特征以及土地利用类型和地形等因子对其的影响。结果表明:1)球状模型可以很好地拟合土壤水分在垂直方向的半变异函数曲线,其存在强烈或中等程度的空间自相关,变程范围从2～5m不等;2)果园对土壤水分含量的影响主要表现在1～2m深度,5月份含量最高,且分布均匀,8月份由于气温和叶面蒸腾作用,水分含量最低。坡耕地和梯田的水分含量都较高,垂直变化不明显,梯田的土壤水分含量最低月份是9月,比坡耕地晚1个月,这是因为所种作物的主要生长季节为9月份,这期间消耗水分较多而造成的。林地由于根系发达,对土壤水分垂直方向的变化的影响比较大,变化为先增大、再减小、最后再增大且分布趋于平缓。灌木林的土壤水分含量整体较低,主要变化深度范围集中在0～2m;草地的土壤水分含量较高,垂直变化的深度范围集中在1m以内;3)坡度、坡向地形因子和土壤水分的垂直方向变异特征没有呈现明显的相关性。Taking the semivariogram in geostatistics as a main analytical tool,this paper studied the spatial variability of soil moisture vertical distribution,and its relations to the land use type and topography in hilly and gully watershed region of Loss Plateau.The semivariogram curve of soil moisture vertical distribution could be well fitted by spherical model,suggesting that there was a strong or moderate spatial autocorrelation.The variation range was 2-5 meters.Orchard mainly affected the soil moisture content at the depth of 1-2 meters.In May,the soil moisture content was maximal and showed a uniform distribution;while in August,the soil moisture content was minimal because of the high air temperature and strong leaf transpiration.In sloping farmland and terrace,soil moisture content was relatively high,and had less vertical change.Terrace had the minimal soil moisture content in September,one month later than sloping farmland.Due to the developed tree root system,woodland had greater effects on the variability of soil moisture vertical distribution,which was manifested in a trend of increase-decrease-increase-getting stable.Overall speaking,shrub land had lower soil moisture content,whose vertical variation mainly occurred at the depth of 0-2 meters,while grassland had higher soil moisture content,whose vertical variation mainly occurred at the depth of 1 meter or less.The spatial variability of soil moisture vertical distribution had no correlation with topographical factors slope and aspect.

关 键 词：土壤水分 半变异函数 空间自相关 

分 类 号：S152.7[农业科学—土壤学]