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盐渍土膜下滴灌过程中的土壤理化性质存在空间变异性,对灌溉管理有一定影响。该文根据3个不同尺度下土壤采样及颗粒尺寸分布(PSD)测定结果,探讨了土壤PSD分维和颗粒体积分数之间的定量关系,分析了各尺度和综合尺度下土壤PSD分维和颗粒体积分数的经典统计特征和地质统计特征,根据颗粒体积分数的半方差函数计算了不同尺度颗粒体积分数的分形维,并做出了等值线图。研究表明,土壤PSD分维与黏粒的体积分数呈正相关关系,黏粒体积分数增大引起PSD分维增加的原因在于细颗粒的比表面积比粗颗粒的大;各尺度土壤PSD分维及颗粒体积分数均无强变异特征;不同尺度下土壤PSD分形维的半方差函数中块金和基台值均非常低;50m尺度土壤PSD分维和黏粒体积分数的等值线图具有类似的集中度和走势,而砂粒体积分数和粉粒体积分数则具有相反的集中度和走势。该研究说明土壤PSD分维和颗粒体积分数都有一定的尺度依赖性。
The physical and chemical properties of soil during the drip irrigation process of salinized soil have spatial variability and have certain influence on irrigation management. According to the results of soil sampling and particle size distribution (PSD) measurements at three different scales, the quantitative relationship between PSD fractal dimension and particle volume fraction was discussed. The fractal dimension and the integrated scale were used to analyze the PSD fractal dimension and the particle volume fraction According to the classical statistical features and geostatistical characteristics of the particles, the fractal dimension of the particle volume fraction at different scales was calculated according to the semivariogram function of particle volume fraction, and the contour map was made. The results showed that the fractal dimension of PSD was positively correlated with the volume fraction of clay. The reason why the fractal dimension of PSD increased with the increase of clay volume fraction was that the specific surface area of fine particles was larger than that of coarse particles. The volume fraction of the soil PSD showed no strong variation. The nugget and abutment values of the fractal dimension of soil PSD under different scales were very low. The contours of the PSD fractal dimension and the clay volume fraction of 50m scale soil had similar concentration And trends, while the sand volume fraction and the volume fraction of particles have the opposite concentration and trend. This study shows that both PSD fractal dimension and particle volume fraction have certain scale dependence.