土壤水盐空间变异性及其尺度效应的多重分形分析

Analysis on spatial variability of soil water and salt and it's scale effect based on multifractal

土壤水盐空间变异性及其尺度效应是农田土壤水盐精准调控的重要依据。本文采用多重分形理论研究了河套灌区农田土壤表层的土壤含水率、土壤EC(Electrical Conductivity)值的空间变异性及其尺度效应。结果表明:3种不同采样尺度下,土壤含水率和土壤EC值具有明显的多重分行特征,随着采样尺度的增大,土壤含水率和土壤EC值的空间变异性有增大趋势,土壤含水率的多重分形奇异谱曲线的对称性较好,土壤EC值的多重分形奇异谱曲线呈现左钩状,说明土壤EC值的空间变异性很弱。多重分形谱能够描述不同尺度下土壤水盐空间分布的不规则特征,能够更好地揭示区域土壤水盐空间分布的局部信息,准确反映土壤水盐的尺度效应。

The soil water and salt distribution has spatial variability and scale effect,which is an impor-tant basis for agricultural soil water and salt accurate control,and also have important instruction signifi-cance for agricultural water management. In this paper,the Hetao irrigation district was chosen as an exam-ple for studying,the classical statistics and multifractal theory were used to analyze the spatial variabilityand scale effect of surface soil water content and soil EC(Electrical Conductivity)values. The results showthat the soil water content and soil EC values have obvious multifractal characteristics under different threekinds of sampling scale,the spatial variability of soil water content and soil EC values increased with theincrease of sampling scales,the symmetry of soil water content and soil EC values of multifractal singulari-ty spectrum curve is good,the shape of multifractal singularity spectrum curve of soil EC values presentleft hook,its spatial variability is very weak. As a result,multifractal parameters can be used to describethe irregular features of soil water and salt under different sampling scales,can better reveal the local infor-mation of the spatial distribution of soil water and salt,accurately reflect the soil water and salt scale ef-fect,and it is a potential indicator to reflect the spatial variability of soil water and salt.