scholarly journals Technique for preparation thin sections of structural soil aggregates of certain size fractions

2019 ◽  
Vol 19 (2) ◽  
pp. 55-58
Author(s):  
V. M. Yakovenko
Keyword(s):  
Pore Space ◽  
Soil Aggregates ◽  
Standard Technique ◽  
Morphological Properties ◽  
Structural Units ◽  
Genetic Horizon ◽  
Thin Sections ◽  
Natural Resin ◽  
Natural Resins ◽  
Large Soil

Morphological properties of poil aggregate aer developed in the process of pedogenesis and reflect the complex of structure formation processes. The peds' size, shape, and internal structure are peculiar to each corresponding soil type and genetic horizon. The technique proposed allows preparing thin sections on every sizes of structural units and, in contrast to known methods, it provides not only a ped immobilization in the mass of fixing material, but also pore space saturation with natural resin. It is also possible to prepare the sections with marking of large aggregates orientation in space; it requires application of gypsum marks on the aggregate surface in the process of their sampling from the soil profile. The technique modified consists of following stages: selection of aggregates with required fractions; preparation of sections with separate aggregates larger than 5 mm; preparation of sections with aggregations smaller than 5 mm. In preparation of aggregates larger than 5 mm, a technique similar to that of preparing large soil block samples is used because it makes possible to process each soil aggregate separately. Another approach is required for processing of structural units up to 5 mm in size because it is impossible to prepare a section of individual issue with this size. The problem is solved when the units are saturated and processed not separately, but as a whole block sample which include a mass with peds of separate fraction. For this purpose, it is required to prepare cups comprised of walls from thick paper and a gypsum bottom. For preparation the caps use a gypsum in the form of fine white powder rapidly solidified in addition of water in a certain proportion and forms a firm bottom of the paper сup. Cut out a square of 4×4 cm in size and a strip from thick paper and glue them together to gain a tube of 5 cm in height and 1.5–2 cm in diameter (i.e. 10×5 cm). Apply on the paper squares a prepared gypsum mass sufficient to retention of the paper tube until gypsum hardening.  Fill a fraction of aggregates into the prepared cup in one-third of its height and cover it with prepared fixing substance with solvent. Saturation is carried out in accordance with the standard technique of section preparing using natural resins (Gagarina, 2004). After complete saturation, paper cups with a mass of aggregates in them turn into monoliths that should be processed in the same way as large soil samples. As a result of all operations, significant number of structural soil aggregates with same sizes may be found within the section plane.

scholarly journals Morphology of forest ravined soil formation on deluvial loams

2015 ◽  
Vol 16 (3-4) ◽  
pp. 5-17
Author(s):  
V. M. Yakovenko ◽  
N. A. Bilova
Keyword(s):  
Forest Soil ◽  
Forest Soils ◽  
Genetic Relationships ◽  
Humus Content ◽  
Morphological Properties ◽  
Genetic Profile ◽  
Structural Units ◽  
Genetic Horizon ◽  
Morphological Studies ◽  
The Individual

The paper establishes the general features of the soil morphogenesis in ravined forests of Dnieper Prysamaria and genetic relationships of forest soils with zonal chernozem under herbaceous associations based on the detection of morphological properties that are «lithogenic», that is inherited from deluvial material and «pedogenic» features formed directly in the forest soil. The study area is located on the Dnieper Prysamaria (Dnipropetrovsk region) within the area of the steppes. The trial areas are incorporated in the upper Deep ravine, located in the upland part of watershed landscape. Catena is represented by five typical sections – between edging of the ravined forest and the field in the middle thirds of the slopes of the northern and southern exposures and in the thalweg of the ravine. Samples for meso-morphological studies were selected by genetic horizons, samples for soil horizons were selected using a soil drill. Basic morphological characteristics were determined in the laboratory (except for the hardness index). The mathematical processing of the results was carried out by methods of nonparametric statistics (method K-means). It was found that, despite the temporal and spatial disorder of deluvial material deposition processes and the differences of the water regime in the thalweg on the slopes, in the ravined biogeocenoses the forest soils are formed with common features of morphological organization of the genetic profile of the individual and morphological properties. The uniformity of the general structure is shown in a set sequence and the power of the genetic horizons, polycyclic and texture eluvial-illuvial differentiation of the genetic profile. The uniformity of the changes in the profile of the individual morphological properties is shown in the form of colour options of genetic horizons (due to humus content talus deposits), changing the particle size distribution of horizons in accordance with the general differentiation profile on eluvial and illuvial (due lessivage) part, changes in the morphology and dimensions of structural units related to changes in the structure of hardness horizons intensive leaching of carbonates from the profile of forest soils. The necessity of research processes clayization profile in situ, their role in the morphogenesis of compacted horizons are noted. There are two groups of properties that make it possible to analyze the micromorphology level communication between the soils in the catena. The first – a lithogenic conditionally or diluvial material properties, which persist for a long time in a forest soil – granulometry and less coloration horizons. The second – a pathogenic properties, sharply differing in the studied soils associated with the peculiarities of morphogenesis of a particular genetic profile and specific genetic horizon. These include the level of occurrence of carbonates in the profile and intensity of effervescence, the morphology of the structural units, the hardness of the genetic horizons, the level of spot colour. Cluster analysis identified a statistically illustrates the differences between the morphological structure of the soil catena, combining in one cluster the ravined soils on deluvial deposits under forest vegetation, and in the other – the soils on the loess under herbaceous vegetation. The contrast of differences increases down the profile.

Correlation of Pore Structure and Permeability by SEM-Image Analysis

1990 ◽  
Vol 48 (1) ◽  
pp. 428-429
Author(s):  
C. A. Callender ◽  
Wm. C. Dawson ◽  
J. J. Funk
Keyword(s):  
Image Analysis ◽  
Pore Structure ◽  
Imaging System ◽  
Pore Space ◽  
Simulation Models ◽  
Image Analyzer ◽  
Imaging Data ◽  
Sem Images ◽  
Thin Sections ◽  
Rock Types

The geometric structure of pore space in some carbonate rocks can be correlated with petrophysical measurements by quantitatively analyzing binaries generated from SEM images. Reservoirs with similar porosities can have markedly different permeabilities. Image analysis identifies which characteristics of a rock are responsible for the permeability differences. Imaging data can explain unusual fluid flow patterns which, in turn, can improve production simulation models.Analytical SchemeOur sample suite consists of 30 Middle East carbonates having porosities ranging from 21 to 28% and permeabilities from 92 to 2153 md. Engineering tests reveal the lack of a consistent (predictable) relationship between porosity and permeability (Fig. 1). Finely polished thin sections were studied petrographically to determine rock texture. The studied thin sections represent four petrographically distinct carbonate rock types ranging from compacted, poorly-sorted, dolomitized, intraclastic grainstones to well-sorted, foraminiferal,ooid, peloidal grainstones. The samples were analyzed for pore structure by a Tracor Northern 5500 IPP 5B/80 image analyzer and a 80386 microprocessor-based imaging system. Between 30 and 50 SEM-generated backscattered electron images (frames) were collected per thin section. Binaries were created from the gray level that represents the pore space. Calculated values were averaged and the data analyzed to determine which geological pore structure characteristics actually affect permeability.

Permeability-porosity transforms from small sandstone fragments

Geophysics ◽  
2006 ◽  
Vol 71 (1) ◽  
pp. N11-N19 ◽  
Author(s):  
Ayako Kameda ◽  
Jack Dvorkin ◽  
Youngseuk Keehm ◽  
Amos Nur ◽  
William Bosl
Keyword(s):  
Pore Space ◽  
Petroleum Industry ◽  
Rock Physics ◽  
Three Dimensions ◽  
Absolute Permeability ◽  
High Porosity ◽  
Drill Cuttings ◽  
Thin Sections ◽  
Numerical Experimentation ◽  
The Absolute

Numerical simulation of laboratory experiments on rocks, or digital rock physics, is an emerging field that may eventually benefit the petroleum industry. For numerical experimentation to find its way into the mainstream, it must be practical and easily repeatable — i.e., implemented on standard hardware and in real time. This condition reduces the size of a digital sample to just a few grains across. Also, small physical fragments of rock, such as cuttings, may be the only material available to produce digital images. Will the results be meaningful for a larger rock volume? To address this question, we use a number of natural and artificial medium- to high-porosity, well-sorted sandstones. The 3D microtomography volumes are obtained from each physical sample. Then, analogous to making thin sections of drill cuttings, we select a large number of small 2D slices from a 3D scan. As a result, a single physical sample produces hundreds of 2D virtual-drill-cuttings images. Corresponding 3D pore-space realizations are generated statistically from these 2D images; fluid flow is simulated in three dimensions, and the absolute permeability is computed. The results show that small fragments of medium– to high-porosity sandstones that are statistically subrepresentative of a larger sample will not yield the exact porosity and permeability of the sample. However, a significant number of small fragments will yield a site-specific permeability-porosity trend that can then be used to estimate the absolute permeability from independent porosity data obtained in the well or inferred from seismic techniques.

Micromorphology of soil structure - Description, quantification, application

Soil Research ◽  
1991 ◽  
Vol 29 (6) ◽  
pp. 777 ◽  
Author(s):  
AJ Ringrose-Voase
Keyword(s):  
Soil Structure ◽  
Pore Space ◽  
Structural Parameters ◽  
Thin Sections ◽  
Physical Measurements ◽  
Undisturbed Samples ◽  
Structure Description ◽  
Management Techniques ◽  
Pore Types ◽  
Soil Behaviour

Micromorphological observation can provide insights into soil structure and aid interpretation of soil behaviour. Undisturbed samples are taken in the field and impregnated. They are used to prepare thin sections or images of the macropore structure using fluorescent photography. Sections can also be obtained at macro, meso and submicroscopic scales. The various elements of soil structure observed micromorphologically can be classified into pore space, physical, distribution and orientation fabrics, and associated structures. Examples of the importance of features in each category are given. Image analysis, especially when computerized, provides a way of parameterizing micromorphological observations. To date it has been used primarily on images of macropore space at the meso and microscopic scales. Such images can be digitized and segmented to show pore space and solid. The pore space can be allocated to pore types. This aids the estimation of 3-D parameters from I-D and 2-D measurements made on the image using stereology. Various ways of using structural parameters to compare structures are discussed. Applications for micromorphological observations, especially when quantitative, include comparison of structures formed by different management techniques. Structural measurements can aid interpretation of soil behaviour as described by physical measurements. They also have a role in estimating the representative elementary volume, on which physical measurements should be made, and in calibrating field estimates of soil structure.

Distribution of Weed Seed Among Soil Structural Units

Weed Science ◽  
1985 ◽  
Vol 33 (2) ◽  
pp. 182-189 ◽  
Author(s):  
Mario R. Pareja ◽  
David W. Staniforth ◽  
Gilda P. Pareja
Keyword(s):  
Depth Distribution ◽  
Soil Depth ◽  
Soil Aggregates ◽  
Conventional Tillage ◽  
Soil Aggregate ◽  
Soil Samples ◽  
Reduced Tillage ◽  
Weed Seed ◽  
Structural Units ◽  
Seed Distribution

The depth distribution of weed seed, their location in relation to soil aggregates, and the size distribution of soil aggregates were determined in fields that had been under continual conventional or reduced tillage for more than 12 years. Soil samples were taken at three depths in the spring and fall of 1982, and soil aggregates were classified into seven size classes by dry, rotary sieving. Subsamples were deflocculated and washed through sieves to recover weed seed. In the spring, 85% of all seed in the reduced-tillage and 28% of those in the conventional-tillage soil were in the 0- to 5-cm-depth layer. Conventional tillage incorporated weed seed uniformly into various soil aggregate classes, whereas with reduced tillage more seed accumulated in the unaggregated fraction of the soil. In the fall, weed seed distribution in relation to soil depth and among soil aggregate classes was similar for both tillage regimes.

Development of a novel image analysis procedure to quantify biological porosity and illuvial clay in large soil thin sections

Geoderma ◽  
2017 ◽  
Vol 292 ◽  
pp. 135-148 ◽  
Author(s):  
Ophélie Sauzet ◽  
Cécilia Cammas ◽  
Jean Marc Gilliot ◽  
Manon Bajard ◽  
David Montagne
Keyword(s):  
Image Analysis ◽  
Analysis Procedure ◽  
Thin Sections ◽  
Large Soil

scholarly journals Comparison of digital image analysis methods for morphometric characterization of soil aggregates in thin sections

2020 ◽  
pp. 199-222
Author(s):  
O. O. Plotnikova ◽  
T. V. Romanis ◽  
P. G. Kust
Keyword(s):  
Soil Aggregates ◽  
Morphometric Parameters ◽  
Thin Sections ◽  
Whitney Test ◽  
Semiautomatic Segmentation ◽  
Mann Whitney Test ◽  
Segmentation Methods ◽  
Adobe Photoshop ◽  
High Degree

The purpose of this study was to investigate the applicability of semiautomatic segmentation methods for obtaining and evaluating morphometric parameters of soil aggregates in artificially prepared loose samples in soil thin sections. The object of the research is typical arable Chernozem. The aggregates were separated by wet sieving method from loose sample of upper 10 cm of the plowing horizon after erosion by a model shallow water flow on a large erosion tray. The aggregates, loosely scattered on the glass and fixed with polyester resin, were used to produce the thin sections. Images of the thin sections were taken under a polarizing microscope and then were processed using two methods compared: Adobe Photoshop + CTan and Thixomet Pro. Data on morphometric parameters of aggregates were obtained: the shape factor, the degree of roundness and the coefficient of aggregate surface roughness. The convergence of the results obtained using Photoshop + CTan by three researchers was evaluated by comparing samples using the Student's test and the Mann-Whitney test. The convergence of the averaged results obtained using Photoshop + CTan and the results obtained using Thixomet Pro was evaluated using the Mann - Whitney test. No significant differences were found between the parameters of the same aggregates obtained using a combination of Adobe Photoshop and CTan programs by different researchers. No significant differences were found between the parameters of the same aggregates obtained by the compared methods. So, one can conclude that the reliability of determining the morphometric parameters of soil aggregates using Thixomet Pro is comparable to the reliability of results when working with images of sectionsin CTan after binarization in Adobe Photoshop. The method of obtaining data on morphometric parameters of soil aggregates using Thixomet Pro completely eliminates the possibility of subjective error, shows a high degree of automation, reproducibility and reliability of the results obtained, and is faster.

scholarly journals Ecological and micromorphological research of soils of the central floodplain of the Samara river

2014 ◽  
Vol 15 (3-4) ◽  
pp. 89-99
Author(s):  
O. V. Strizhak
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Soil Profile ◽  
Chemical Elements ◽  
Pore Space ◽  
Chip Surface ◽  
Secondary Electrons ◽  
Thin Sections ◽  
Electron Mode ◽  
Scanning Electron

The influence of environmental factors on the formation of microforms typical for soils of the central river floodplain Samara and mechanisms of formation of the soil profile have been considered. The attention is paid to the identification and soil genesis of cutana. To achieve the goals the micromorphological research methods and techniques of scanning electron microscopy have been used. The decoding of soil thin sections has been carried out in the standard scheme. The relief of chip surface was studied in the secondary electrons, the homogeneity of the distribution of chemical elements - by the surface of the secondary electrons, the chemical composition of the studied surface areas was received by a microroentgen-spectral analysis. The studies have shown the main features in the microstructure of these soils. In the profile the microstructure is inhomogeneous, in the upper horizons is silty-plasma, changes with the depth to sand-plasma and in the lower horizons – plasma-sand. The skeleton grains are characterized by the following transfer on their surface (scratches) and by a good roundness. Plasma is humus-clay, with the depth the clayey plasma decreases. It is typical for the clay part of the plasma two refractive indices, the orientation and the ability to restructure. The pore space is the most developed in the upper horizons, thanks to digging activity of earthworms. With the depth the pore area decreases and often the pore walls cover with clayey cutanas for the illuvial processes. As a result of intensive impacts of nutrient factors, the upper horizons are well-structured. In each profile you can select several kaprolit horizons. For this kind of profile the humus mull is more typical. Kutana complex is represented by clay cutana. In the upper horizons they are poorly expressed, are not present in all pores. Down to the profile their quantity in the pores increases, they become more pronounced. The explanation of the chip surface using a scanning electron microscopy confirmes the mobility of plasma and illuvial origin of cutana. The data obtained in the secondary electron mode and microanalysis shows the monotony of addition with minor bright zones which belongs to titanium or chromium-containing minerals. The features of the microstructure of the soil profile in central floodplain are conditioned by the floodplain processes. With the reduction of their influence, because of the increase between the periods of flood and their intensity, the forming role of biological factors increases.

scholarly journals INFLUENCE OF ANTHROPOGENIC FACTORS ON THE SOIL CONDITION OF THE N.V. TSITSIN MAIN BOTANICAL GARDEN OF RAS

2021 ◽  
Vol 1 (4) ◽  
pp. 1-10
Author(s):  
O.V. Martynenko ◽  
◽  
V.N. Karminov ◽  
P.V. Ontikov ◽  
◽  
...  
Keyword(s):  
Soil Compaction ◽  
Anthropogenic Impact ◽  
Pore Space ◽  
Soil Condition ◽  
Botanical Garden ◽  
The State ◽  
Morphological Properties ◽  
Anthropogenic Factors ◽  
Reference Plot ◽  
Sampling Plot

The territory of the N.V. Tsitsin Main Botanical Garden of the Russian Academy of Sciences is subjected to significant anthropogenic stress, which has a negative effect on the state of valuable collections of tree and shrub species. Soil compaction is one of the most dangerous consequences of anthropogenic impact, expressed in increased recreational impact. In this context, the botanical garden was very concerned about the deterioration of the collection of elaeagnus species. Therefore, the soils on which these plants grow were chosen as the object of research. On this territory, three sampling plots with different degrees of anthropogenic impact were laid. Sampling plot No. 1 had the maximum anthropogenic impact. The area of medium anthropogenic impact was represented by the sampling plot No. 2. The sampling plot No. 3 where the anthropogenic impact was minimal was a reference plot. All the studied soils were classified as soddy-slightly podzolic medium loamy soils (Umbric Albeluvisols Abruptic). Fundamental differences in the morphological properties of the studied soils were that the soils located in the area of maximum anthropogenic impact, starting from a depth of 40 cm, showed gley spots, which were not found in other soils. Increased bulk density of soil in undisturbed state corresponded to increased anthropogenic impact. This led to a decrease in total pore space of soil. Soil compaction contributed to a noticeable decrease in gravimetric soil water content in upper horizons. At the same time, worsening of subsurface runoff contributed to gley-forming processes in the illuvial part of the profile. Cluster analysis revealed good grouping of the dependence of the studied indicators on the severity of anthropogenic impact. The studied indicators were separated depending on their type and position in the profile. The conducted study made it possible to assess the essential physical and hydrophysical properties of soils on the part of the territory of the Main Botanical garden of RAS that is occupied by the valuable collection of elaeagnus. Based on the results of the study, a set of measures is proposed that can significantly reduce the identified negative effects and improve the state of both the studied soils and stands growing on them in general.

scholarly journals Intra-aggregate CO<sub>2</sub> enrichment: a modelling approach for aerobic soils

2013 ◽  
Vol 10 (2) ◽  
pp. 1209-1218 ◽  
Author(s):  
D. Schlotter ◽  
H. Schack-Kirchner
Keyword(s):  
Soil Solution ◽  
Water Saturation ◽  
Pore Space ◽  
Soil Aggregates ◽  
Co2 Storage ◽  
Gas Diffusion ◽  
Solution Chemistry ◽  
Aerobic Respiration ◽  
Small Scale ◽  
Soil Solution Chemistry

Abstract. CO2 concentration gradients inside soil aggregates, caused by the respiration of soil microorganisms and fungal hyphae, might lead to variations in the soil solution chemistry on a mm-scale, and to an underestimation of the CO2 storage. But, up to now, there seems to be no feasible method for measuring CO2 inside natural aggregates with sufficient spatial resolution. We combined a one-dimensional model for gas diffusion in the inter-aggregate pore space with a cylinder diffusion model, simulating the consumption/production and diffusion of O2 and CO2 inside soil aggregates with air- and water-filled pores. Our model predicts that for aerobic respiration (respiratory quotient = 1) the intra-aggregate increase in the CO2 partial pressure can never be higher than 0.9 kPa for siliceous, and 0.1 kPa for calcaric aggregates, independent of the level of water-saturation. This suggests that only for siliceous aggregates CO2 produced by aerobic respiration might cause a high small-scale spatial variability in the soil solution chemistry. In calcaric aggregates, however, the contribution of carbonate species to the CO2 transport should lead to secondary carbonates on the aggregate surfaces. As regards the total CO2 storage in aerobic soils, both siliceous and calcaric, the effect of intra-aggregate CO2 gradients seems to be negligible. To assess the effect of anaerobic respiration on the intra-aggregate CO2 gradients, the development of a device for measuring CO2 on a mm-scale in soils is indispensable.

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