不同土层土壤水分特征曲线的空间变异及其影响因素

Spatial Variability of Soil Water Retention Curve in Different Soil Layers and Its Affecting Factors

利用多重分形和联合多重分形方法,对陕西杨凌地区0～20 cm和20～40 cm土层van Genuchten模型参数的空间变异性及其影响因素进行了研究。结果表明:0～20 cm和20～40 cm土层参数α都具有明显的多重分形特征,空间变异性较强,且分别是由低值和高值分布引起的;参数n和θs的多重分形特征不明显,空间变异性较弱。0～20 cm和20～40 cm土层van Genuchten模型参数与土壤物理特性的相关特征并不完全相同,在观测尺度上,0～20 cm土层参数α与Sand、Silt显著相关,参数n与Sand、SOM显著相关,θs与Sand显著相关;20～40 cm土层参数α与SOM显著相关,参数n和θs都与Sand、Silt、SOM显著相关;在多尺度上,0～20 cm土层参数α与Sand、Silt的相关程度最高,20～40 cm土层参数α与BD、SOM的相关程度最高。

Spatial variability of van Genuchten model parameters and its affecting factors in 0～20cm and 20～40cm soil layers were studied with multifractal and joint multifractal methods.The results showed that in 0～20cm and 20～40cm soil layers parameter had obvious multifractal characteristics,and its spatial variability was strong caused by the distribution of lower and higher values respectively.The multifractal characteristics of parameter n and θs were not obvious,and the spatial variability was weak.Correlation characteristics between van Genuchten model parameters α and soil physical properties in 0～20cm and 20～40cm soil layers were analyzed.At the observation scale,the correlations between parameter n and sand and silt content were significant,the parameter n and sand and organic matter content had remarkable relationship,and θs was significantly related to sand content in 0～20cm soil layer.The relationship between parameters α and organic matter content was remarkable,and the parameter n and θs were significantly related to sand,silt and organic matter content in 20～40cm soil layer.At the multiple scales,correlations between parameters α and sand and silt content were most obvious in 0～20cm soil layer,and parameters α were remarkably related to bulk density and organic matter content in 20～40cm soil layer.