Submitted to: American Society of Agronomy Meetings
Publication Type: Abstract Only
Publication Acceptance Date: June 1, 2003
Publication Date: November 2, 2003
Citation: Pachepsky, Y.A., Rawls, W.J. 2003. [CD-ROM]. Using fractal models in scaling and pedotransfer functions of soil hydraulic properties. American Society of Agronomy Meetings. November 2-6, 2003. Denver, CO. paper #899293. Technical Abstract: Geometric irregularity and heterogeneity are inherent features of soils. Fractal geometry provides explicit parameterization of the irregularity in surfaces and outlines, and fractal models can be fitted to many types of soil data. Using fractal geometry in soil studies strives for (a) quantifying changes in the irregularity and heterogeneity, (b) interpreting proxy measurements of soil geometric properties, (c) helping to upscale and downscale soil data, (d) improving descriptions of soil variability, (d) supporting integration of results from different disciplines. Fractal models are usually applicable in scale ranges less than 1.5 - 2 orders of magnitude. Within such scale ranges, fractal models explain scale dependencies in water and solute transport parameters. Pedotransfer functions are used to estimate soil hydraulic properties from basic soil data for modeling in many large-scale projects and pilot studies. Scale corrections are needed in such estimates because the size of soil samples is usually very different from the size of elementary volume in the models. A promising approach to upscaling soil properties is using data from fine scales to generate model parameters at a coarser scale. Fractal models are useful in this respect because they can simulate the presence of rare occurrences in soil structure that greatly affect hydraulic properties.