Impacts of clay mineralogy and physiographic units on the distribution of potassium forms in calcareous soils in Iran

Clay Minerals ◽  
2009 ◽  
Vol 44 (3) ◽  
pp. 327-337 ◽  
Author(s):  
S. Rezapour ◽  
A. A. Jafarzadeh ◽  
A. Samadi ◽  
S. Oustan
Keyword(s):  
Calcareous Soils ◽  
Clay Mineralogy ◽  
Soil Formation ◽  
Alluvial Plain ◽  
X Ray Diffraction ◽  
Piedmont Plain ◽  
Physiochemical Properties ◽  
Exchangeable K ◽  
North West ◽  
Diffraction Patterns

AbstractThe potassium pools of five major physiographic units of the Urmia region situated in western Azerbaijan province, north-west Iran, were studied to determine the distribution of K forms as functions of clay mineralogy and physiographic units. Soil samples from horizons of ten pedons were selected and analysed for physiochemical properties, clay mineralogy and forms of K. X-ray diffraction patterns revealed that the soils were similar in clay-mineral compositions, consisting of illite, smectite, chlorite, and kaolinite, for the different physiographic units, but vary in the relative amounts of these minerals. The illite content was highest in piedmont plain (P.P) followed by plateau (Pl), river alluvial plain (R.A.P), colluvial alluvial plain (C.A.R) and lowland (L.L) units. Smectite content was highest in Pl followed by P.P, L.L, R.A.P and C.A.P units. Several processes, such as the diversity of weathering rate, biocyclying processes of K accumulation, geomorphologic conditions and soil formation processes, caused significant differences in most K forms in the soils. A wide variation in total K (HF-extractable K) (0.54–1.1%), non-exchangeable K (280–450 mg kg–1) and exchangeable K (217–330 mg kg–1) occurred among the physiographic units, corresponding to variations in their mineralogical compositions, mainly the abundance of illite. Significant differences (P ⩽ 0.05) were found for K, HNO3-extractable K and non-exchangeable K between the soils with large illite contents (30–50%) and with small illite contents (10–30%). A significant positive relationship existed between mineral K and illite content (r2 = 0.85, P ⩽ 0.001) and non-exchangeable K and illite content (r2 = 0.84, P ⩽ 0.001). The results indicated that these pools of K are mainly released from the frayed edges and wedge zones of illite.

The forms of potassium and potassium adsorption in some virgin soils from south-western Australia

Soil Research ◽  
1999 ◽  
Vol 37 (4) ◽  
pp. 695 ◽  
Author(s):  
Y. Pal ◽  
R. J. Gilkes ◽  
M. T. F. Wong
Keyword(s):  
Western Australia ◽  
Agricultural Soils ◽  
Clay Mineralogy ◽  
Sorption Isotherms ◽  
Clay Content ◽  
Water Soluble ◽  
X Ray Diffraction ◽  
Exchangeable K ◽  
The North ◽  
Southern District

This investigation was undertaken to determine the potassium (K) status and adsorption behaviour of 227 samples from horizons of 41 representative virgin soil profiles, extending from Geraldton in the north to the Great Southern district of Western Australia. X-ray diffraction analysis of random powder of whole soil indicated that quartz is the dominant mineral and some soils contain significant amounts of feldspars. Clay mineralogy is dominated by kaolinite but minor quantities of illite are present in some soils. Most south-west Australian agricultural soils contain little available K: NaHCO3-extractable K (NaHCO3-K, median value 0·09 cmol K/kg, equivalent to 35 mg K/kg soil), HNO3-extractable K (HNO3-K, median value 0·30 cmol K/kg, equivalent to 117 mg K/kg soil), and total K (XRF determined K, median value, 17 cmol K/kg, equivalent to 6630 mg K/kg soil). The proportion of water-soluble K (H2O-K) ranges from 0 to 3·5% of total K, 0 to 76% of HNO3-K, and 0 to nearly 100% of exchangeable K. Exchangeable K ranges from 0 to 100% (median value 37%) of HNO3-K. These are relatively high proportions of H2O-K and exchangeable K compared with soils from many other parts of the world. The amounts of all forms of K variously increase or decrease downwards in the soil profile depending on both clay content and mineralogy. The commonly assumed increase in K with clay content alone is invalid. The soils mostly have low-to-moderate values of K sorption capacity, ranging from 5% to 67% (median value 14%) of added K (initially 4·1 mM K/L, equivalent to 4·1 cmol K/kg). otassium sorption isotherms conform well to the Freundlich equation. The inability of the Langmuir equation to describe the data may indicate that there are several types of K sorption sites in these soils. The Gapon coefficient KG varied widely from 0·04 to 29·8 (L/mol) ½ [median value 5·4 (L/mol) ½ ].

Morphological, physical, and clay mineralogy of calcareous and gypsiferous soils in North of Lorestan, Iran

2019 ◽  
Vol 99 (4) ◽  
pp. 485-494
Author(s):  
Kolsum Rahman Salari ◽  
Mohammad Amir Delavar ◽  
Mehrdad Esfandiari ◽  
Ebrahim Pazira
Keyword(s):  
Electron Microscopy ◽  
Calcareous Soils ◽  
Clay Mineralogy ◽  
Limited Information ◽  
Soil Taxonomy ◽  
Kaolinite Clay ◽  
Piedmont Plain ◽  
Transmission Electron ◽  
Parent Rocks ◽  
Pedogenic Processes

There is limited information about the genesis, classification, and properties of calcareous and gypsiferous soils of western Iran. This study investigated the morphological, physical, and mineralogical characteristics of soils on different physiographic units, including plateau, colluvial fans, and piedmont plain in the Aleshtar region. The results indicated that the parent materials (calcareous and gypsiferous) as well as topographic conditions had the most influence on the soil profile development, pedogenic processes, and clay mineralogy. Illite, chlorite, smectite, palygorskite, and kaolinite clay minerals were identified using X-ray powder diffraction, transmission electron microscopy, and scanning electron microscopy. Illite, chlorite, and kaolinite have genetically been inherited from parent rocks. Neoformation of smectite and palygorskite other than genetic inheritance was formed as a result of calcite and gypsum precipitation and poor drainage. Calcareous soils with the petrocalcic horizon and gypsiferous soils contained more pedogenic palygorskite. In conclusion, we suggest adding a new great group of Gypsixerepts to the soil taxonomy to reflect the presence of pedogenic gypsum in Inceptisols.

Possible effects of land use on the clay mineralogy of a brown forest soil

Clay Minerals ◽  
2002 ◽  
Vol 37 (4) ◽  
pp. 663-670 ◽  
Author(s):  
D. C. Bain ◽  
D. T. Griffen
Keyword(s):  
Land Use ◽  
Clay Mineralogy ◽  
Parent Material ◽  
X Ray Diffraction ◽  
Brown Forest Soil ◽  
X Ray ◽  
Close Proximity ◽  
Diffraction Patterns ◽  
Effects Of Land Use ◽  
Brown Forest Soils

AbstractThree soil profiles classed as brown forest soils on schistose parent material, in close proximity but under different land uses, have been studied. The profile under 50 year-old Sitka spruce trees is the most acidic, the second profile under rough grassland is less acidic, and the third profile in an arable field which has been fertilized is the least acidic. The clay fractions (ς μm) of all three profiles are very similar. However, computer simulations of the X-ray diffraction patterns of clay phases using a modified version of NEWMOD revealed two possible weathering trends: (1) an increasing proportion of vermiculite in interstratified mica-vermiculite in the upper horizons of the arable and forested soils; (2) formation of high-charge corrensite by weathering of chlorite in all three profiles but least pronounced in the arable soil. The differences in clay mineralogy amongst the profiles are minor, but these two different weathering trends may be due to the effects of different land use.

Effect of continuous cropping on potassium forms and potassium adsorption characteristics in calcareous soils of Iran

Soil Research ◽  
2008 ◽  
Vol 46 (3) ◽  
pp. 265 ◽  
Author(s):  
A. Samadi ◽  
B. Dovlati ◽  
M. Barin
Keyword(s):  
Sugar Beet ◽  
Clay Fraction ◽  
Calcareous Soils ◽  
Chemical Properties ◽  
Continuous Cropping ◽  
Soil Series ◽  
Exchangeable K ◽  
North West ◽  
Adsorption Characteristics

The potassium (K) status of 5 major soil types, under sugar beet cultivation for 35–40 years, and adjoining virgin lands were compared. Fifty-nine paired surface soil samples belonging to 24 soil series from the major sugar beet growing areas in Western Azarbaijan province located in the north-west of Iran were studied to ascertain whether relative K form sizes and K adsorption behaviour of the soils are being changed by long-term cropping. The samples were analysed for soil physical and chemical properties, mineralogy of clay fraction, different forms of K, and K adsorption characteristics. The soils are alkaline and calcareous. The K-bearing mineral illite is the dominant clay mineral in Typic calcixerepts, Typic haploxerepts, and Typic endoaquepts, whereas in Vertic calcixerepts and Vertic endoquepts, the clay mineralogy is dominated by smectite. A highly significant relationship (r2 = 77, P ≤ 0.001) was observed between CEC and smectite content. No changes in K-bearing minerals were detected due to cropping and K depletion. Soil solution K (So-K) constituted 1.7% of exchangeable K (Ex-K) and 1.4% of non-exchangeable K (NEx-K) for the cultivated soils and 1.8% of Ex-K and 2% of NEx-K for the adjacent virgin land. A pronounced significant decline (P ≤ 0.001) in the Ex-K content from 507 to 270 mg/kg (a drop of 45%) and a less significant degree (P ≤ 0.05) in the So-K content from 28 to 12 mg/L (a drop of 55%) were detected in the soil series of Typic calcixerepts as a result of long-term cropping. Continuous sugar beet cropping did not result in changes in the NEx-K contents in any soils except in Vertic endoaquepts containing low illite. A highly significant positive relationship (r2 = 0.79, P ≤ 0.001) was observed between values of NEx-K and illite contents, indicating that this form of K is mainly released from the frayed edges of illite. Paired t-test revealed that continuous sugar beet cultivation increased significantly (P ≤ 0.01) K adsorption in Typic calcixerepts, Typic haploxerepts, and Vertic endoaquepts, where exchangeable K was decreased as a result of intensive cultivation.

scholarly journals Mixed-Layer Illite-Smectite in Pennsylvanian-Aged Paleosols: Assessing Sources of Illitization in the Illinois Basin

Minerals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 108
Author(s):  
Julia A. McIntosh ◽  
Neil J. Tabor ◽  
Nicholas A. Rosenau
Keyword(s):  
Mixed Layer ◽  
Acid Leaching ◽  
Soil Formation ◽  
Illinois Basin ◽  
Formation Processes ◽  
X Ray Diffraction ◽  
Diagenetic Alteration ◽  
Mineral Alteration ◽  
Diffraction Patterns ◽  
The Impact

Mixed-layer illite-smectite (I-S) from a new set of Pennsylvanian-aged Illinois Basin underclays, identified as paleosols, are investigated to assess the impact of (1) regional diagenesis across the basin and (2) the extent to which ancient environments promoted illitization during episodes of soil formation. Interpretations from Reichweite Ordering and Δ° 2θ metrics applied to X-ray diffraction patterns suggest that most I-S in Illinois Basin paleosols are likely the product of burial diagenetic processes and not ancient soil formation processes. Acid leaching from abundant coal units and hydrothermal brines are likely diagenetic mechanisms that may have impacted I-S in Pennsylvanian paleosols. These findings also suggest that shallowly buried basins (<3 km) such as the Illinois Basin may still promote clay mineral alteration through illitization pathways if maximum burial occurred in the deep past and remained within the diagenetic window for extended periods of time. More importantly, since many pedogenic clay minerals may have been geochemically reset during illitization, sources of diagenetic alteration in the Illinois Basin should be better understood if Pennsylvanian paleosol minerals are to be utilized for paleoclimate reconstructions.

Some aspects of the genesis of an alpine humus soil

Soil Research ◽  
1973 ◽  
Vol 11 (1) ◽  
pp. 1 ◽  
Author(s):  
R Brewer ◽  
AD Haldane
Keyword(s):  
Sudden Change ◽  
Clay Fraction ◽  
Clay Mineralogy ◽  
Soil Formation ◽  
Mineral Weathering ◽  
X Ray Diffraction ◽  
X Ray ◽  
Humus Soil ◽  
In Situ Weathering

An alpine humus soil profile has been examined in the field, in thin section and by X-ray diffraction. The presence of a stone line and the sudden change in characteristics across the stone line, including particle size distribution, degree of exfoliation of the micas, major mineral composition, and clay mineralogy suggest that this is a polygenetic profile consisting of two soil stratigraphic units. There has been little pedological reorganization within either unit, soil formation consisting essentially of in situ weathering, removal of soluble constituents, and accumulation of organic matter, with some biological activity, in the upper unit. It is shown that gibbsite derived from weathering of feldspar is a major component of the clay fraction, especially in the lower unit. The clay mineralogy is considered in relation to proposed mineral weathering sequences and weathering in a yellow podzolic soil.

Possible effects of irrigation with wastewater on the clay mineralogy of some Australian clayey soils: laboratory study

Soil Research ◽  
2016 ◽  
Vol 54 (7) ◽  
pp. 857 ◽  
Author(s):  
Serhiy Marchuk ◽  
Jock Churchman ◽  
Pichu Rengasamy
Keyword(s):  
Chemical Composition ◽  
Chemical Properties ◽  
Clay Mineralogy ◽  
Clayey Soils ◽  
X Ray Diffraction ◽  
X Ray ◽  
Physico Chemical ◽  
Soil Clays ◽  
Diffraction Patterns ◽  
Peak Decomposition

Potassium is common in a wide variety of wastewaters and in some wastewaters is present at several hundred to several thousand mg L–1. Potassium is taken up by expandable clays leading to its fixation and illitisation of smectitic and vermiculitic layers. Hence the addition of wastewaters to soils may lead to mineralogical changes in the soils that affect their physico-chemical properties. Winery wastewater was equilibrated with clay-rich soils from Southern Australia. X-ray diffraction patterns and chemical composition of clays extracted from untreated and treated soils were determined. In three of the four soils, shifts in peak positions occurred towards more illitic components along with increases in K and sometimes also Mg and Na contents of soil clays. Peak decomposition showed trends towards the formation of interstratifications of illite with smectite at the expense of smectite and an alteration of poorly crystallised illite into its more well-ordered forms. The results show that illitisation may occur as a result of the addition of K-rich wastewaters to clayey soils.

Evaluation of Freezing Methods by Low Temperature X-Ray Diffraction

1977 ◽  
Vol 35 ◽  
pp. 330-333
Author(s):  
T. Gulik-Krzywicki ◽  
M.J. Costello
Keyword(s):  
Biological Materials ◽  
Molecular Organization ◽  
X Ray Diffraction ◽  
Glass Capillary ◽  
X Ray ◽  
Rate Dependent ◽  
Before And After ◽  
Freeze Etching ◽  
Diffraction Patterns ◽  
Set Up

Freeze-etching electron microscopy is currently one of the best methods for studying molecular organization of biological materials. Its application, however, is still limited by our imprecise knowledge about the perturbations of the original organization which may occur during quenching and fracturing of the samples and during the replication of fractured surfaces. Although it is well known that the preservation of the molecular organization of biological materials is critically dependent on the rate of freezing of the samples, little information is presently available concerning the nature and the extent of freezing-rate dependent perturbations of the original organizations. In order to obtain this information, we have developed a method based on the comparison of x-ray diffraction patterns of samples before and after freezing, prior to fracturing and replication.Our experimental set-up is shown in Fig. 1. The sample to be quenched is placed on its holder which is then mounted on a small metal holder (O) fixed on a glass capillary (p), whose position is controlled by a micromanipulator.

Examination of Rabbit Fc Crystals

1968 ◽  
Vol 26 ◽  
pp. 140-141
Author(s):  
J. P. Robinson ◽  
P. G. Lenhert
Keyword(s):  
Molecular Weight ◽  
Flat Plate ◽  
Phosphate Buffer ◽  
Asymmetric Unit ◽  
X Ray Diffraction ◽  
X Ray ◽  
Neutral Ph ◽  
Small Crystals ◽  
Carbon Coated ◽  
Diffraction Patterns

Crystallographic studies of rabbit Fc using X-ray diffraction patterns were recently reported. The unit cell constants were reported to be a = 69. 2 A°, b = 73. 1 A°, c = 60. 6 A°, B = 104° 30', space group P21, monoclinic, volume of asymmetric unit V = 148, 000 A°3. The molecular weight of the fragment was determined to be 55, 000 ± 2000 which is in agreement with earlier determinations by other methods.Fc crystals were formed in water or dilute phosphate buffer at neutral pH. The resulting crystal was a flat plate as previously described. Preparations of small crystals were negatively stained by mixing the suspension with equal volumes of 2% silicotungstate at neutral pH. A drop of the mixture was placed on a carbon coated grid and allowed to stand for a few minutes. The excess liquid was removed and the grid was immediately put in the microscope.

Quantitative Electron Microscope with imaging plate

1994 ◽  
Vol 52 ◽  
pp. 408-409
Author(s):  
D. Shindo
Keyword(s):  
Electron Microscope ◽  
Dynamic Range ◽  
Processing System ◽  
Digital Data ◽  
Imaging Plate ◽  
Crystal Thickness ◽  
X Ray Diffraction ◽  
Resolution Electron ◽  
Electron Intensity ◽  
Diffraction Patterns

Imaging plate has good properties, i.e., a wide dynamic range and good linearity for the electron intensity. Thus the digital data (2048x1536 pixels, 4096 gray levels in log scale) obtained with the imaging plate can be used for quantification in electron microscopy. By using the image processing system (PIXsysTEM) combined with a main frame (ACOS3900), quantitative analysis of electron diffraction patterns and high-resolution electron microscope (HREM) images has been successfully carried out.In the analysis of HREM images observed with the imaging plate, quantitative comparison between observed intensity and calculated intensity can be carried out by taking into account the experimental parameters such as crystal thickness and defocus value. An example of HREM images of quenched Tl2Ba2Cu1Oy (Tc = 70K) observed with the imaging plate is shown in Figs. 1(b) - (d) comparing with a structure model proposed by x-ray diffraction study of Fig. 1 (a). The image was observed with a JEM-4000EX electron microscope (Cs =1.0 mm).

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