Quantifying preferential flows in porous soils: An original imaging and image processing procedure

With the increasing accessibility of image acquisition techniques, image processing has become an essential component of soil science. Here, Image Processing is specifically used to the accurate prediction of solute transport through soils. To do so, dye tracers are leeched into soil cores to visualize active flow paths in cross sections of soil. We have derived a cheap alternative, using off-the-shelf equipments, as compared to earlier experiments. We still managed to compensate for most of the images acquisition process noise and provided a simple yet correctly correlated data analysis and dye concentration estimation. We tested the method using a fluorescent dye (pyranine) in intact soil cores of a Mexican allophonic (volcanic) soil. The current application of this procedure is the estimation of the pharmaceutical compounds (mostly antibiotics) contamination of agricultural soils irrigated by waste water in the northern central region surrounding Mexico City.