Minkowski Functionals of Connected Soil Porosity as Indicators of Soil Tillage and Depth

Abstract

We made use of 3D tomograms from X-ray computed tomography of soil samples from a vineyard in La Rioja (Spain), to explore the ability of Minkowski functionals of connected soil pore space to discriminate between different pore space geometries coming from soils with different management and depth and that, a priori, are expected to have some degree of dissimilarity. We estimate the volume of the connected pore space ($V$), the surface of the interface soil/void ($S$), the accumulated mean curvature of that interface ($C$) and its connectivity ($E$) out of 3D binary images taken from samples of two different depths of soil where two different managements were undertaken. Logit model showed that $V$, $S$ and $C$ are needed to predict soil management and only $V$ is required to infer depths. In our limited experimental circumstances, where we just explain two soil features, it seems natural that not all the four functionals are related to or needed to explain the variety of considered cases of soil structures. Therefore, this could not be an argument to dismiss Minkowski functionals as good candidates as predictors of the geometric structure of soil pore space. Our results suggest just the opposite, and they can be used as discriminants for a wide variety of soil features and behaviors.