Application of various methodological approaches for assessment of soil micromorphology due to VESTA program applicable to prediction of the soil structures formation

1 General overview on the micromorphological analysis The natural systems consist with mutual interactions at the different hierarchical levels which continuously take place (Gadd, 2007). In aerobic and anaerobic sub-systems reactions between litho-, atmo-, hydro-, and antroposphere generate agronomical important sphere – pedosphere (Juma, 1999). Influence of every natural entity (bio-, chemo-, physic-) from the sub-system should play a key role to form organic matters even by led to bio-geochemical processes such as weathering. Mutual relationship accelerated the mechanical, chemical and biological destruction of primary rocks, minerals and support formation of secondary soil minerals (Čurlík and Kolesár, 2014; Kolenčík et al., 2011). Generally, soil contains from 95 to 99% of inorganic compounds (particles) and from 1 to 5% of organic matters (Juma, 1999; Lal and Shukla, 2004). Soil system poses characteristic ubiquitous interactions and for this reason is obvious to quantify their material composition from atomic background through micro-, and macroaggregate forms up to extrapolation larger geomorphological complexes – landscape systems. On the other side, the microscopic observations could underline the basic and specific chemical and physical properties. One of the most fundamental features of soils is the soil structure (Roger-Estrada et al., 2010).

forces) between soil particles (Grosbellet et al., 2011;Li and Fan, 2014;Hu et al., 2015) however, its stabilization is influenced by internal and external factors, and their interactions (Chenu and Cosentino, 2011;Paradelo et al., 2013;Šimanský et al., 2013;Jozefaciuk and Czachor, 2014;Šimanský and Bajčan, 2014).There are several mechanisms of aggregation.Aggregates are formed in stages, with different bonding mechanisms dominating at each stage (Tisdall and Oades, 1982).Hierarchical theory of aggregation proposes that microaggregates join together to form macroaggregates and the bonds within microaggregates are stronger than the bonds between microaggregates (Edwards and Bremner, 1967).Microaggregates are formed from organic molecules (OM) attached to clay (Cl) and polyvalent cations (P) to form compound particles (Cl-P-OM), which are joined with other particles (Cl-P-OM) to form macroaggregates [(Cl-P-OM)x]y.In addition, the concentric theory of aggregation suggests that external layers are concentrically built upon the external surface of the aggregate, with younger carbon in outer layers of aggregates than in aggregate interiors (Santos et al., 1997).The precipitation of hydroxides, oxides, phosphates and carbonates enhances aggregation.Cations such as Si 4+ , Fe 3+ , Al 3+ and Ca 2+ stimulate the precipitation of compounds that act as bonding agents for primary particles.Cations also form bridges between clay and soil organic matter particles resulting in aggregation.If we can define and quantify these impacts, so we can predict changes in soil structure.One of the most effective tools for assessment of soil structure may be its modeling, which is based on relevant data, which have been described between the phases of soil environment.Basic attribute of model formation is defined elementary relations and interactions as individual mineral phases, and their chemical attractions.Nature of chemico-physical bonds is accordingly examined on the inter-atomic, inter-layer, coordinated, and polyhedral background.Interestingly, the progressive evaluation with long-term effect has had detailed study with phases interface, liner and the vector space coordination which settled mineral reaction stability, their subsistent facets, and overall bond-structural integrity.The possibility of using several methodological approaches for example as: microscopic study or X-ray diffraction analysis could be very useful because they can substantially streamline modeling and predicting of the structural state in soils differing in their genesis and texture under different soil management.During a short time, created a model after substituting variables should know to provide relevant information on the structural state of the soil, which is essential not only from the view point of agronomy (forestry, construction, industry, and etc.).
Due to this reason our work was concentrated on the detailed survey of micromorphological analysis from various methodological points of view.In order to complete concept of theoretical investigation the 2D cross section of soil, modeled X-ray analysis with extrapolated visualization to make 3D design structure and morphology particles in modeled VESTA program was evaluated.Firstly, this work (theoretical concept investigation) introduces as basic background for further study of soil aggregate formation in different soil types.The next section was evaluated the methodological approach examinations, which are mainly attributes for prediction behavior of individual mineralogical phases.In this context it concludes examined structure-spatial relationship and interactions localized in aggregates.
2 Methods for mutual relationship assessment of inorganic particles in soil system

Microstructure analysis in polarization microscopy
Microscopic observation carried out in polarization microscope belongs to basic soil analysis.The 2D cross section soil sample (micromorphological analysis) determines different aspect of interactions and relationships.These details involve particle size distributions, aggregate forms, particles morphology (isomorphic, anhedral, allotriomorphic grains, dominant crystal planes vs. destruction structures, and etc.), homogeneity-heterogeneity of grains, their genetic associations with surrounding grains distribution, for instance, in sand samples it usually examined zircon-rutile-tourmaline index (also called ZRT index).There is some evidence that significant substitution may occurred between CO 3 2-(trigonal planar polyhedron) and PO 4 3-(tetragonal polyhedron) due to their geochemical speciation, structural configuration and equilibrium relationship between hydroxyapatite and calcite (Samasundaran et al., 1985, Kuo, et a., 2009).
Evaluation of dissolution rate (aggregate stability) could be affected by soil pH, concentration of P and Ca, moisture content and particle size distribution (Kuo et al., 2009).The effect of particle size range come from its inverse relation to particular surface area associated with dissolution being interfacial (surface) controlled process.
Presented samples from figure 1 and figure 2 were gained from calcite saturated horizon localized on the loess.Generally, from these observations it can be deduced type and degree of weathering processes even by possible impact on the mode of mineral (structural) disintegration accompanied with elements mobilization (Barker et al., 1998;Čurlík, 2011).Both mentioned phases

Physico-chemical analysis of soil, separation technique for X-ray analysis particle evaluation
Overall assessment of average soil sample in individual soil types (in the Slovak Republic -Morphogenetic system of soils in Slovakia, 2014; in the World -classification of WRB, 2006), we have to do multiple types of chemical and physical analysis.We have to start from the previously known information on external and internal factors and their interactions that fundamentally affect soil structure (Bronick and Lal, 2005) González et al., 2007).Šucha et al. (1993) as the first step samples have to be pulverized in agate mortal under 0.2 mm followed by ultrasonic probe disintegration.Subsequently, treated sodium acetate buffer and sodium dithionite conducted with minimize organic content recommend using by H 2 O 2 .For better interpretive form of clay mineral due to expandable layers performed on the X-ray analysis saturation by the ethylene-glycol accompanied with vapour for 8 h at 60 °C is profitable procedure.

X-ray diffraction analysis
X-ray diffraction analysis is the most common technique for identification and characterization minerals (clay minerals, carbonates, etc.) from various type of matrices (Čurlík, 2011;Čurlík and Kolesár, 2014;Markgraf and Reeder, 1985;González et al., 2007).The X-ray analysis (beam of rays) belongs to part of electromagnetic spectra which be generated by the swift movement braking with fast flux electrons on the physical barrier.By means of goniometer with detector is scanned to the X-ray diffraction measurement.Interactions between X-ray with crystal structure one another atom become sources of X-ray scattering with the same wavelength.
Produced beams has interfered each other and generate many characteristic diffraction maximums.Export X-ray diffraction analyses are data directly interlinked with from X-ray beams where diffraction maximums shows different kind length and width displayed in digital record (Prince et al., 1999).In case of generated data we further can use it for soil system with various modeling/ calculating and visualization evaluations.

Application of VESTA program for inorganic substances in soil system and their specific assessment
Acquirement of completely diffraction data could serve as numerical calculates to the crystalline parameters, for instance define crystal structure, linear and space groups, unit cell dimension, fraction coordinates, and lattice angle α, β, γ, and a-, b-, c-distance, etc. (Table 1).
In natural system, atoms, ions, ligands etc. attempt to stabilize (coordinated) with minimum energy and maximal efficiency.Due to this reason minerals with precise physical parameters and stoichiometric pure forms have tendency coordinated with symmetrically repeated equivalent identity (unit cell) in 3D space of crystal lattice.There is some evidence that X-ray analysis provides highly applicable background for detail physicochemical specification of soil inorganic substances.It may be the case that the primary and secondary minerals (inorganic minerals) with different value of crystallinity contained dominant components.

Conclusions
Observation of interrelations in 2D micromorphological cross section analysis could define their chemical equilibrium, local thermodynamically details, potential reactivity, spatial configuration on the atomic level.
Based on the clear define (discrete vector parameters), predicted the mode of chemical and mechanical disintegration and decomposition accompanied with formation of new thermodynamically stable secondary minerals.Assessment sequence and successive models for mobilization, distribution, and bioavailability based on observed soil reactive products.Form "ideal" soil samples are profitable to use dominant minerals for X-ray analysis deal with modeled in VESTA program.This is applicable from the view point of detailed specification for determine several interactions e.g.water medium (dispersive system -hydrophobic interaction) for soil solution, natural bio-geochemical cycles and prediction mechanisms inorganic substances in soil system.Apparently, this topic underlines theoretical introduce investigation of methodological approach and is desirable to apply this model in the real condition at the near future.

Figure 1 Figure 2 Figure 3
Figure 1 Examples of 2D micromorphology of soil cross section are shown mineralogical association of stable phases of hydroxyapatite (HA), and calcite (C).The reaction rim (C) contains insignificant content of quartz, Fe-hydroxides and clay minerals.Visualized arrow has pointed interface between two dominant phases, inserted line have 0.2 mm, and visualization was performed in unpolarized light