Showing 13 results for Clay Minerals
Ali Ashraf Amiri Nejad, Majid Bagher Nejad,
Volume 2, Issue 4 (1-1999)
Abstract
The calcification of soils and the effects of topography on this process were studied in semi-arid regions of Kermanshah. From a toposequence, based on the previous soil surveys of the region, five profiles were selected, and field studies and laboratory analyses were carried out on soils. Alluvial - colluvial fans, piedmont alluvial plains, and old plateaux were three main physiographies on the selected toposequence. Soil moisture and temperature regimes were Xeric and Thermic, respectively. The results indicate that redistribution of carbonates and soil formation processes may be categorized in four specific stages to be described in the text. Accumulation of calcium carbonates in soil profiles showed two basic forms: one in sandy layers of fine - textured soil profiles under the influence of abrupt textural changes and lower permeability, and the second in subsurface horizons of soils with calcareous parent material. The morphological evidences showed that in addition to translocation from upper horizons of carbonates by solution and suspension, physical movements to subsurface layers of fine calcareous materials have also affected the formation of calcic horizons. In other words, CaCO3 may have moved as fine particles through soil cracks and subsequently accumulated in the lower horizons. Soil mineralogy showed considerable amounts of illite, Chlorite, smectite and palygorskite clay minerals. Some pedogenic transformations of illite and chlorite may have caused formation of smectite and palygorskite.
A. A. Safari Sinejani, G. Emtiazi, H. Shariatmadari,
Volume 6, Issue 3 (10-2002)
Abstract
Soil organic matter and clay minerals adsorb and immobilize extracellular enzymes of microorganisms and increase soil enzymes stability. This study aims to clarify the relative importance of soil organic matter and clay minerals on the cellulolytic activities of soils. Fluca prepared cellulase was immobilized on some agricultural residues and clay minerals, avicel and a sample of soil. Immobilized exoglucanase and endoglucanase were assayed at different times. Activities of the immobilized enzymes were strikingly dependent on the kind of sorbent. After 20 days of storing in refrigerator at 4oC, the deactivation of immobilized enzymes on the organic substances (as avicel) was very low but deactivation of immobilized enzymes on the soil and clay minerals was relatively high. On the other hand, the activities of immobilized enzymes on the agricultural residues and avicel were significantly higher than the soil and clay minerals. So it may be concluded that a large part of cellulolytic activity of soil is related to immobilized enzymes on agricultural residues. Coating of the clay minerals, soil and avicel with 4 mmol of Al (OH) x per mg of them significantly increased their immobilization capacity and activities of immobilized enzymes. Activities of immobilized exoglucanase and endoglucanase on the Ca- homoionized soil and clay minerals were significantly higher than the K- homoionized soil and clay minerals. However, these effects may be related to the specific effects of cations on the method of enzyme assay or enzymes activities. These homoionizing-cations effects on the activity of immobilized enzymes on avicel were not significant.
M. H. Salehi, H. Khademi, M. Karimian Eghbal,
Volume 7, Issue 1 (4-2003)
Abstract
Clay minerals have considerable effects on physico-chemical properties of soils. Using different techniques, mineralogy of silicate clays and their formation were investigated in selected soils from Chaharmahal and Bakhtiari Province. The study area is about 1300 ha and its soil moisture and temperature regimes are xeric and mesic, respectively. Geomorphologically, the area consists of different landforms including pediments, outwash, hills and piedmont plain. After field and laboratory studies, five representative pedons were selected in previously determined mapping units and samples were taken for the analyses required. Clay particles from two surrounding rock formations and selected soil samples were separated and examined by electron microscopy (SEM and TEM), X-ray diffraction and infrared techniques.
Illite, smectite, chlorite, palygorskite and kaolinite were present in all the soils. Considering the fact that palygorskite was not observed in nearby rock formations, this mineral is probably formed by pedogenic processes. Smectite, on the other hand, has been inherited from parent materials and also transformed from palygorskite. Other minerals had been probably inherited from parent materials. Infrared spectra confirm the X-ray diffraction and submicroscopic results.
H. R. Karimzadeh, A. Jalalian, H. Khademi,
Volume 8, Issue 1 (4-2004)
Abstract
Clay minerals deserve special attention as they play a crucial role in many soils. The clay mineralogy of five gypsiferous soils from different landforms in eastern Isfahan was investigated using X-ray diffraction (XRD). In addition, soil aggregates and wind-deposited sediments were examined by scanning electron microscope (SEM) and analyzed by energy dispersive X-ray analyzer (EDX).
The results indicate the presence of palygorskite, mica, kaolinite, chlorite, and quartz with a trace amount of vermiculite and randomly interstratified layers in all soils. Smectite occurs in soils of both the piedmont plain and old river terrace, but not in the alluvial fan soils. Mica, chlorite, quartz, and kaolinite were probably inherited from the parent material. Palygorskite seems to increase with depth in the alluvial fan, whereas, in the old terrace soils, this clay mineral decreases with depth. Palygorskite present in alluvial fan soil appears to have been formed authigenically when the basin was covered with shallow hyper-saline lagoons toward the end of the Tertiary. Palygorskite in the old terrace seems to be mostly detrital and an eolian origin of palygorskite is likely because a large amount of palygorskite is present in upper soil horizons. A higher proportion of smectite in deep soils of the old terrace, as compared with palygorskite, suggests the possibility of authigenic formation of smectite from palygorskite.
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R Molavi, M Baghernejad, E Adhami,
Volume 13, Issue 49 (10-2009)
Abstract
Fire is widely used to clear farms in Iran, while there is little information regarding the effects of fire on the characteristics, especially mineralogy of soils. The objectives of the present study were to 1) compare some physico-chemical properties of burned and unburned soils and 2) evaluate minerals transformation in top soil layer resulting from increasing temperature. Soil samples were taken from 0-5 and 5-15 cm depths of two burned places, an agricultural soil from Takht-e-Jamshid area and Bamoo forest, in four replications. Physico-chemical analyses were carried out on burned and unburned samples. X-ray diffraction technique was used to identify minerals of clay fraction in 0-5 cm depth burned and unburned soil, and also to compare transformation of minerals (if any) after heating at 300˚C and 600˚C for 2, 4, 8 and 12 h. Burning increased soil pH and sand sized fraction in 0-5 cm, and P and K in both depths of Bamoo forest. Changes in soil properties of agricultural filed were negligible. XRD analyses showed the reduction in the intensity peaks of chlorite and illite after burning. Lower relative quantity of chlorite and illite was observed in various times of 300˚C treatment in comparison to control, while they were not observed in 8 and 12 h of 600˚C. No change was observed in the peak of quartz in forest and field soils after burning and after various heat treatments.
M. Liaghat, F. Khormali, S. A. Movahedynaeini, E. Dordipour,
Volume 16, Issue 61 (10-2012)
Abstract
Studies on the soils of western Golestan province show that regardless of increased rain and presence of clay minerals with high cation exchange capacity, potassium extractable with ammonium acetate is low. In order to find the reason for this low amount of available K, clay minerals and micromorphology of the soil porosity were studied. Twenty disturbed and undisturbed samples from each horizon were taken for physicochemical properties, mineralogy and micromorphological studies. Four selected profiles included Gypsic Aquisalids, Typic Endoaquepts, Typic Calcixerolls and Typic Hapludalfs. The results showed that in addition to the clay content and type of clay minerals in soils that can affect soil available K (Kava.), it seems soil porosity can also affect Kava. mainly through their effects on extension of roots, water and nutrients transmission. Favorable content of clay and dominance of smectites in Mollisols and also higher porosity and dominance of channel porosities caused the presence of higher Kava, in these soils. presence of HIS. poor soil drainage, reduction of Fe3+ in smectite crystal lattice in Inceptisols, and also less amount of porosities caused the presence of higher potassium fixation and reduction of Kava. in these soils.
H. R. Owliaie, M.najai Ghiri,
Volume 17, Issue 65 (12-2013)
Abstract
Paddy soils provide the staple diet for nearly half of the world's population. The formation of the Anthrosols is induced by tilling the wet soil (puddling), flooding and drainage regimes associated with the development of a plow pan and specific redoximorphic features. The aim of this study was to evaluate the effects of long-term rice cultivation on physico-chemical properties and clay mineralogy of soils of three rice farms and compare the results with adjacent virgin lands in Yasouj region. Paddy soils exhibited larger contents of clay, organic carbon, saturation percentage, cation exchangeable capacity, cation exchange activity classes, electrical conductivity and lower content of calcium carbonate equivalent compared to non-paddy soils. This land use showed higher proportions of Feo, Fet and lower content of Fed. No such differences were noticed with the type of clay minerals in both land uses. Paddy soils contained greater amount of smectite, particularly in the surface horizons. Smectite in paddy soils exhibited lower layer charge and higher degree of crystallinity compared to non-paddy soils. Transformation of illite and chlorite to expandable minerals is a possible mechanism for lower amounts of these minerals in paddy soils.
S. Jafari, H. Nadian,
Volume 18, Issue 69 (12-2014)
Abstract
The aim of this study was to evaluate soil properties changes in a soil toposequence series in Khuzestan province. Twelve soil profiles were dug in north to south direction in this province, according to the changes of the slope in Karoon’s alluvial deposits. The results showed that soil texture regularly changes to heavier form from north to south. It was slightly of redoxomorphic features in low land. Therefore, salic horizon was formed in this land. Despite high water table in this area, gray or mottle forms were few due to high soil salinity. The carbonates were eluviated from surface to subsurface horizon therefore, calsic horizon was formed due to illuviation. Secondary carbonate accumulation was maximum in the studied area. Both classic horizon and cambic horizon were formed in some pedons under long time cultivation in north regions. These developments were originated from organisms that grew under good drainage class. The smectite was seen in the south part of region. It may have been transported by river and deposited under high salinity and flocculated in contact to Persian Gulf’s saline water. The palygorskite was not seen in all patterns. This clay was removed in pedons under long time cultivation in the north area due to more leaching. High irrigation water can accelerate palygorskite transformation. Also, the XRD patterns showed that chlorite, illite, kaolinite and quartz were main clay minerals in the studied soils.
M. Pishgir, S. Jafari,
Volume 18, Issue 69 (12-2014)
Abstract
This study was done to compare K+ and NH4+ fixation in different agricultural systems in Khuzestan province. Soil samples were collected from Shushtar and Abadan. Samples were collected from depths of 0-30 and 30-60 cm in sugarcane, multi cropping, palm and uncultivated land. Then, 0-50-100-200-400-600-800-1000 mg kg-1 K+ or NH4+ concentrations were added to 0.5 gram of clay separated from these soil samples. These clay samples were kept for 24 h at room temperature. Then, they were extracted with 0.5 M magnesium acetate, and K+ and NH4+ were determined by flame photometer and micro diffusion methods, respectively. Fixed K+ or NH4+ was determined from added and extracted cations. Also, XRD studies were done in some samples. Kaolinite, palygoreskite, illite, chlorite, smectite and quartz were identified by XJRD. Statistical analysis showed that K+ or NH4+ fixation and rate were increased by increasing the concentration. Maximum K+ or NH4+ were fixed in surface layer’s clay in Shushtar multi cropping and Abadan Palm cultivation. The results showed that K+ and NH4+ fixation were increased by increasing the concentration. But, under increasing concentration for a cation, fixation decreased for others and vice versa. NH4+ fixation was more than K+. This may be due to smectite clay mineral in these samples. Smectite group tend to cause NH4+ fixation more than K+. These results can be applied for K+ or NH4+ fertilizers management.
S. Shakeri, S. A. Abtahi,
Volume 22, Issue 4 (3-2019)
Abstract
This research was carried out to assess the origin and clay minerals characteristics and their relationship with potassium forms in the calcareous soil of this region, with the humid climate conditions. Based on aerial photos and topographic maps, physiographic units were separated and soil sampling was done in each diagnostic horizon. The results showed that smectite was the main and dominant clay mineral in the study area. In well-drained pedons, the convincing process for smectite abundance seemed to be mainly the transformation of palygorskite and mica. According to the results, the exchangeable potassium in the surface horizon was higher than that of the subsurface horizons. The main reason for the higher level of exchangeable K in the soil surface, was more smectite and organic carbon. The results revealed that unlike exchangeable and non-exchangeable K, because of the suitable conditions like temperature and humidity in surface horizons, the relative mean of structural K in the surface soils was less than that in the subsurface. Also, since an increase in calcium carbonate resulted in a decrease in amount of clay and the amount of relative clay minerals (dilution effect), the amounts of exchangeable, non- exchangeable and structural K were decreased.
V. Shahrokh, H. Khademi, H. Shariatmadari,
Volume 23, Issue 2 (9-2019)
Abstract
Despite the great importance of potassium applied as a fertilizer in the orange orchards, no information is currently available regarding the rate of potassium release from rhizosphere and the bulk soils of such trees. The objectives of this study were to investigate the weathering of micaceous minerals and their non-exchangeable K release and also, to examine the status of different forms of K in the rhizosphere and bulk soils of orange orchards with different ages in Darab, Fars Province. Samples were, accordingly, taken from the rhizosphere and bulk soils of orange orchards with the ages of 5, 10 and 20 years; also, virgin soils (control) were obtained from three soil depths including 0–30, 30–60, and 60–100 cm. Water soluble, exchangeable and nonexchangeable K, and the clay mineralogy of the soils were determined. The results demonstrated that the concentration of soluble and exchangeable K in the cultivated soils was less than that in the control soil and that the concentration of nonexchangeable K in the soils of 20-year-old orchards was less, than that in other soils. Soluble and exchangeable K values decreased with depth in all soils. Clay mineralogy investigation also showed that the quantity of illite decreased and that of smectite and illite-smectite increased as the age of orange trees was raised. With increasing the age of orange trees and root development, more potassium could be taken up from soil and more changes occurred in the soil minerals. In order to avoid a very high decline in the reserved K in the soils under orange trees, particularly in the orchards with older trees, K fertilization has to be taken more seriously based on the soil testing results.
F. Khayamim, H. Khademi, S. Ayoubi,
Volume 24, Issue 2 (7-2020)
Abstract
Understanding the abundance of clay minerals in soil and also, their spatial variability can provide more comprehensive information about soil properties, behavior and functions. The objectives of this research were: (i) to map the spatial distribution of the dominant clay minerals in the soils of Isfahan Province and its relationship with climate and parent materials, and (ii) to determine the quantity of the dominant clay minerals in different climatic classes of Isfahan Province. The amount of palygorskite, illite, expanded minerals and chlorite were semi-quantitatively determined for 100 soil samples collected from Isfahan Province. Maps of the dominant clay minerals were prepared by the Inverse Distance Weighting method. The results showed that palygorskite mostly occurred in the soils of dry areas with higher temperature throughout the province. This mineral was not present in the more humid areas of the province. Besides, palygoskite was found to be dominant in the soils derived from the Qom Formation, as well as Lower and Upper Red Formations belonging to Miocene and Pliocene. It seems, therefore, that the parent material plays a major role in entering palygoskite to the soil system, while the dry climate mostly guarantees the stability of this clay minerals and, to some extent, its limited neoformation in such soils. Both illite and chlorite occur in all soils throughout the province, regardless of their climate, following no particular trend. This may indicate that parent materials play a major role in the occurrence of these minerals. Both climate and parent material appear to have affected the distribution of expandable clays in the soils. In more humid areas of the province (west and southwest), climate plays a larger role in the distribution of this mineral. In other areas of the study region, especially in the eastern parts of the province with a much drier climate, the role of the parent material on the dominant soil clay minerals is more pronounced.
S. Shakeri, A. Azadi, M. Saffari,
Volume 24, Issue 4 (2-2021)
Abstract
Determining the relative distribution of each chemical form of the elements and their relationship with the physical, chemical, and clay mineralogical properties of soils can help researchers to achieve the sustainable agricultural management. The present study was conducted to evaluate the chemical forms of four micronutrients (Zn, Cu, Fe and Mn) in some surface and subsurface soils of Kohgiluyeh and Boyer Ahmad province and their relationship with the physical, chemical and mineralogical properties of the soils. The results showed that the exchangeable and sorbed chemical forms of the studied elements were very low and negligible, but the residual, carbonate, and organic forms had the highest to lowest values of the chemical forms of these elements, respectively. Examination of the correlation of the chemical forms of these elements with soil properties showed the effective correlation of organic carbon values with the Zn chemical forms; also, there was a correlation between clay, silt, cation exchange capacity and calcium carbonate and the chemical forms of Cu, Fe and Mn. The correlation between the quantities of clay minerals and the chemical forms of these elements showed that the amounts of different forms of the studied elements were directly related to 2:1 clay silicate minerals (especially vermiculite). Evaluation of Fe and Mn chemical forms also showed that the amounts of these elements were higher in the soils with developed profiles (Alfisol and Mollisol), the wetter climate and zeric moisture regime rather than in soils with non-developed profiles (Entisols and Inceptisols) and a drier climate and a ustic moisture regime. In general, the results showed that variations of soil forming factors such as climate (as well as the total amount of each micronutrients), could be effective on the chemical forms of micronutrients (especially on Mn and Fe); these can be effective in the management of weakly to highly-developed soils orders.
