太行山山前坡地不同土地利用方式下土壤水分的时空变异特征

以济源试区坡耕地、苹果园、果农复合系统、退耕还林地、刺槐林地5个邻接农林模式为研究对象,用时域反射仪(TDR)测定坡面不同农林模式雨季前、雨季中和雨季后表层土壤(0-30 cm)含水量,分析表层土壤水分分布特征及其时空变异特征。结果表明:由于受不同坡位、不同植被类型的影响,土壤表层含水量从坡顶到坡底逐渐增加;雨季前后土壤表层含水量的半方差理论函数均呈球状模型,块金值变化并不明显,其值分别为0.25和0.30,独立间距分别为99.7 m和87.6 m,土壤水分具有强烈的空间自相关性,存在很好的分形特征,分形维数分别为1.71和1.74,变异均主要是由空间自相关部分引起。雨季中土壤表层含水量的半方差函数呈直线模型,土壤水分空间变异表现出随距离增加而增加,分形维数为1.40。

Spatiotemporal Variability of Soil Moisture under Different Land Use Patterns of Taihang Mountains

Measured the cover soil water content in soil layer 0-30 cm of different agroforestry landscape types in Ji-yuan with TDR,the landscape types including sloping cropland,apple orchard,apple-clover system,land under forest and grass changed from grain crop and black locust forest.Analyze the distribution characteristic and spatiotemporal variability of the cover soil water.The result showed that the soil water has renewed in a certain extent after a rain period in 1.5 m soil profile;the soil water content is gradually increased from the top of to the bottom of the slope under the affection of the slope location and plant category.The theory model of semivariogram for cover soil water content before rain season and after season,the value of nugget is changed no obviously,and they are 0.25 and 0.30;ranges is 99.7 m and 87.6 m.And the results indicated that soil moisture exhibited high fractal dimensions and clear spatial autocorrelation.The fractal dimensions are 1.71 and 1.74,variogram is main autocorrelation.During rain season the theory semivariogram model is linear,the spatiotemporal variability of soil water content becomes higher with the increase in distance,and its fractal dimension is 1.40.