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.

Accounting for soil architecture and microbial dynamics in microscale models: Current practices in soil science and the path ahead

“…The models described in the previous subsection rely on a huge amount of information contained in soil images, which is constantly increasing due to steady improvements of imaging techniques. Today, 3D CT images that are routinely acquired require several tens of gigabytes of storage for a size of up to about 2000 3 voxels (Helliwell, Sturrock, Miller, Whalley, & Mooney, 2019;Koebernick et al, 2017;Quigley, Rivers, & Kravchenko, 2018;San José Martínez, Martín, & García-Gutiérrez, 2018). The numerical solvers of the pore-scale models that directly include CT images as input data, such as LBM or finite volume resolutions, require large computational and memory capabilities.…”

A framework for modelling soil structure dynamics induced by biological activity

“…These functions reflect complementary aspects of soil structure and should therefore have relevance for many different processes in soils (San José Martínez, Martín, & García-Gutiérrez, 2018;Vogel et al, 2010). For example, the surface area controls the interactions of solutes between water-filled pores and solid surfaces, while the curvature gives information on pore shape, which may be relevant for soil mechanical properties (Vogel et al, 2010).…”

“…The Minkowski functions represent a concise way to describe the geometry and topology of a multiscale binary medium (Vogel, Weller, & Schlüter, 2010), being defined as the volume and connectivity of each phase and the surface area and curvature of their interface, expressed as a function of pore diameter. These functions reflect complementary aspects of soil structure and should therefore have relevance for many different processes in soils (San José Martínez, Martín, & García‐Gutiérrez, 2018; Vogel et al., 2010). For example, the surface area controls the interactions of solutes between water‐filled pores and solid surfaces, while the curvature gives information on pore shape, which may be relevant for soil mechanical properties (Vogel et al., 2010).…”

Bypass and hyperbole in soil research: Worrisome practices critically reviewed through examples

“…Contrary to allegations made by several staunch defenders of the aggregate concept (Wang et al, 2019b; Yudina & Kuzyakov, 2019), it is in general impossible to identify aggregates in 3D CT images of soil samples, even in the case of columns filled with artificially repacked aggregates. Nevertheless, mathematical techniques exist, and novel ones are continuously being developed, to quantify the geometry of the pore space and account for it explicitly in computer models of soil dynamics, making unnecessary any mention of aggregates (e.g., Houston et al, 2017; Rabot, Wiesmeier, Schlüter, & Vogel, 2018; San José Martínez, Martín, & García‐Gutiérrez, 2018; Vogel & Roth, 2001; Vogel, Weller, & Schlüter, 2010).…”