The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
The connectivity of pore space is an important topological property of soil. Together with the porosity and the pore-size distribution, it governs the transport of water, solutes and gases.This paper describes the Euler-Poincare characteristic (EPC) as an index of connectivity of soil pore space in three dimensions, and shows how the EPC can be estimated by analysing pairs of parallel images, so-called...
Morphological investigations can be used to reveal the nature and distribution of solid matter and pore space within a porous medium, such as rock, soil or milled peat. When sampling milled peat, it is necessary to ensure that disturbance during sample collection and transportation is minimised, and a field impregnation is required to preserve the structure of the milled peat as it exists in the stockpile...
A new method for the acquisition of undisturbed in situ samples of milled peat (non-cohesive particulate material) suitable for image analysis was developed. Samples were obtained in the field by dripping Endura epoxy resin onto a stockpile surface. Blocks of material (160 mmx120 mm) with original pore structure up to 140 mm deep were removed to the laboratory and re-impregnated with Crystic resin...
In order to study the physical properties of gypsiferous soils (Gypsic Xerochrepts and Typic Xerofluvents) from an irrigated semi-arid area in Catalonia (NE Spain) and their relationships to their pore characteristics, twenty horizons with gypsum contents ranging between 0 and 90% were sampled for micromorphological and physical analyses. The micromorphological study consisted of thin section description...
This paper describes the application of fractal geometry to the study of the structure and dynamics of tilled silty topsoil. The soil structure of each topsoil sample has been experimentally quantified directly by image analysis and indirectly by both water retention and mercury porosimetry. Any fractal scaling laws were mostly determined within a relevant common pore radius yardstick scale. Their...
A fundamental question to be answered for studies in quantitative micromorphology at varying scales is: What is the minimum area on a soil thin section or block that is required to represent the pedofeature of interest based on its distribution in soil space? This paper investigates the necessity of establishing a representative elementary area (REA) in the study of pedofeatures for quantitative analysis...
Poor root development due to constraining soil conditions could be an important factor influencing health of urban trees. Therefore, there is a need for efficient techniques to analyze the spatial distribution of tree roots. An analytical procedure for describing tree rooting patterns from X-ray computed tomography (CT) data is described and illustrated. Large irregularly shaped specimens of undisturbed...
Use of sequential images of an impregnated soil block (6x2x2 cm) were used to compare two dimensional (2D) and three dimensional (3D) aspects of pores in an Italian Vertisol. Standard image analysis methods are used to represent and measure the properties of the pores represented in the images. It is clear that not all 3D properties can be predicted with the same precision using 2D images. This is...
Recent research examining water movement in milled peat stockpiles has focused on macroscale physical data. Structure is important with respect to water movement and storage; the number, shape and size of macropores is thought to be particularly important in influencing by-pass flow. A study of pore structures quantified by image analysis techniques was conducted starting with a field impregnation...
In a central Amazonian pasture, a single earthworm species, Pontoscolex corethrurus, becomes very abundant (400 ind. m -2 ) after forest clearing. Its casts form a compact, continuous and impermeable crust with a thickness of 20 cm. To analyze the structural modifications, we established a field experiment in which soil blocks from the forest were implanted in the pasture, and soil blocks...
There is general interest in quantifying soil structure in order to obtain physically based parameters relevant to transport processes. To measure the surface fractal dimension of the pore-solid interface we use approaches known from fractal geometry. The characteristics of this interface, expressed by its fractal dimension, are descriptors of the heterogeneity and complexity of soil structure. Samples...
Physical methods that examine water content and movement in soils are often based on assumptions that the soil is isotropic and homogeneous. For a non-cohesive, porous material such as milled peat, these assumptions are likely to be unrealistic. Soil morphology provides data that cannot be obtained by physical methods, although such measurements are only relevant when applied to a soil in a physical...
Quantitative micromorphological approaches have been developed for a variety of purposes in recent years. This paper describes a methodology developed for contexts where the spatial distribution of a large number of small objects is of interpretative value, and where colour is a determining criteria of the object description. Such contexts include anthropic soils, particularly plaggen soils, and geoarchaeological...
Solute transport studies are increasingly being used to characterise flow mechanisms in both the field and laboratory. Realisation that solutes move preferentially through soil into groundwaters has meant that research in this area has increased in importance. The objectives of this study were to develop a method for the high-resolution examination of transport mechanisms in the laboratory, using...
Observations by 2D image analysis on four clay-rich agricultural soils in laboratory wetting and drying experiments indicate that the aggregation process changes the size distributions of soil materials in producing more irregular, larger particles which form through the accumulation of both small and large particles. The effect is more important with depth in laboratory and field samples. The distribution...
In this study, we exploit dye patterns to identify flow types in macroporous soils as a step forward from using dye patterns simply as qualitative pictures that illustrate preferential flow. Dye tracer experiments at different irrigation rates and initial soil moisture conditions were carried out on three hillslope sites. Several vertical and horizontal soil sections were prepared after each experiment...
This paper evaluates the extent to which image analysis can be applied to determining faunal impacts on soils. It is based on experience gained from a 2-year experiment using an upland grassland soil to investigate impacts on soil micromorphology. Eighty undisturbed samples were collected in June of 1999, 2000 and 2001 from limed and control plots on the Macaulay Institute's Sourhope Research Station...
The aim of this paper is to study changes in water-stable aggregation and void space in an upland grassland soil following a surface application of calcium carbonate intended to increase the diversity of soil fauna. Samples of the H and Ah horizons were collected at the time of the first lime application (June 1999) and 1 and 2 years thereafter. Void space in both horizons was quantified by image...
We propose a small set of fundamental geometric measures which provide a quantitative description of crack patterns at the soil surface including their dynamics. These measures (Minkowski numbers) are combined with tools of mathematical morphology to obtain Minkowski functions. Additionally, we measured the distribution of angles within the crack network to characterize the form of aggregates. The...
The temporal dynamics of soil structure is a typical phenomenon exhibited by shrinking clay soil. It causes substantial difficulties for the characterization of soil properties and for the modeling of fundamental processes such as water flow and solute transport. In this paper, we present a model for crack formation that mimics the physical processes involved. The model is based on a lattice of Hookean...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.