Characterization of soil micromorphology using X-ray computed tomography for predicting saturated hydraulic conductivity.

摘要

New and cross-disciplinary analytical methods are developed and tested for investigation of intact soil micromorphology, the results of which are applied in established fluid models that, classically, rely on indirect measurement of soil microstructure. The developed methods establish a set of requirements for legitimate application of X-ray Computed Tomography (CT) to intact soil, wherein the acquired CT digital image volumes were validated as representing soil structure through a comparison to classic thin section optical spectrum analytic techniques. The established requirements include: three dimensional (3D) post-acquisition processing of CT imagery, which is demonstrated to retain spatial relationships between discrete soil structures; an objective method of segmenting CT imagery into discrete structures that incorporates both the numerical digital number Hounsfield Unit (HU) and the spatial context; and, the use of 3D quantification methods for measurement of discrete soil structures.;Application of the developed processing, segmentation and quantification methods to CT data is utilized in the fulfillment of a series of established and novel saturated hydraulic conductivity (Ks) models. A correlation between the laboratory measured Ks and the CT derived prediction of Ks, via the novel methodology presented, indicates that the direct quantification of soil micromorphology has potential application in future pedologic and fluid dynamics research.