High Trioctahedral Vermiculite Content in the Sand, Silt, and Clay Fractions of a Gray Brown Podzolic Soil in Greece

Alexiades, C. A.; Polyzopoulos, N. A.; Koroxenides, N. S.; Axaris, G. S.

doi:10.1097/00010694-197311000-00005

Cited by 13 publications

(4 citation statements)

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“…Similar relationships have also been observed by Alexiades et al (1973) with particle-size fractions of a soil from Greece developed from granite and containing vermiculite apparently derived from mica. Most notably, in all of these studies VIF values decreased with decreasing particle size.…”

Section: 'Vermiculite' Rich Sand and Silt Fractionssupporting

confidence: 82%

“…Part of this change may be related to true differences in the mineralogy of the different particle-size fractions. For example, Alexiades et al (1973) report kaolinite and considerable pedogenic chlorite in the clay fraction of their soil and no kaolinite and less chlorite in coarser fractions. On the other hand, different particle sizes of a given vermiculite may differ in their cation exchange behavior (Ross and Rich, 1973).…”

Section: 'Vermiculite' Rich Sand and Silt Fractionsmentioning

confidence: 99%

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‘Vermiculite’ Determination on Whole Soils by Cation Exchange Capacity Methods

Coffman

1974

Clays and clay miner.

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Abstract--The proposed method is a modification of one by Alexiades and Jackson (1965). Calcium exchange capacity (CaEC) and potassium exchange capacity (KEC) are determined, after removal of organic matter and free iron oxides, by saturating the exchange complex with centrifuge washings of pH 7 acetate solutions of Ca or K, respectively. Excess salt in solutions remaining in contact with the soil after saturation is determined by measuring the weight and concentration of the excess solution. The exchangeable cations and excess salt are then replaced by centrifuge washings with 1 N acetate solutions of Mg (for CaEC) or~NH, (for KEC), after overnight 110~ oven-drying to enhance K fixation for KEC. The replaced cations are determined and CaEC and KEC values are calculated. Per cent 'vermiculite' is based on the difference between CaEC and KEC (expressed in m-equiv/100 g) and an assumed 'vermiculite' interlayerexchangecapacityof 154 m-equiv/100 g; percentage Vr = (CaEC-KEC/154) • 100. The 'vermiculite' interlayer fraction (VIF) of the CaEC may also be calculated; VIF = CaEC-KEC/CaEC. The measured 'vermiculite' is shown in quotation marks since the method is open to criticism regarding exactly what is being measured, the assumptions made, etc. and to emphasize that the determination procedure is an operational one for the characterization of cation exchange complexes.Removal of free iron oxides increased both CaEC and KEC values of several soils but percentage Fr was little affected. The amount of K fixation was affected by the drying treatment employed after K saturation (none vs air-drying vs oven-drying). Thoroughly crushing Montana and African vermiculites dramatically increased their CEC and measured 'vermiculite' values, but had little effect with two samples of saprolite from chloritic metabasalt.

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Section: 'Vermiculite' Rich Sand and Silt Fractionssupporting

confidence: 82%

Section: 'Vermiculite' Rich Sand and Silt Fractionsmentioning

confidence: 99%

‘Vermiculite’ Determination on Whole Soils by Cation Exchange Capacity Methods

Coffman

1974

Clays and clay miner.

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“…This agreed with Curtin and Smillie (1981), who reported that silt significantly contributes to total CEC when its content is large relative to clay and sand content. This also coincides with McAleese and McConaghy (1957), Martini (1970), and Alxiades et al (1973), who stated that silt and even sand could make a significant contribution to soil CEC. Lower values of R 2 were obtained for the regression equations of all multiple-and single-factor regressions (Table 3).…”

Section: Regression Of Cec On the Different Textural Classes In Individual Entisolssupporting

confidence: 89%

Predicting Soil Cation Exchange Capacity in Entisols with Divergent Textural Classes: The Case of Northern Sudan Soils

Adam

Ibrahim

Sulieman

et al. 2021

Air, Soil and Water Research

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Cation exchange capacity (CEC) is an important soil property because it affects the assimilation of nutrients and buffers against soil acidification. Thus, knowledge of CEC is considered key to developing agricultural and environmental models for land management planning. However, in developing countries such as Sudan, there is a lack of soil CEC data due to the absence of research projects and funding to develop this information. Therefore, this research was conducted to predict CEC for large areas using specific soil physical characteristics, including soil texture and saturation percentage (SP), for which there is potentially available data. To achieve this goal, the properties of 430 soil samples (301 for training and 129 for validation) were obtained from the soil database of the Soil Survey Administration, Ministry of Agriculture, Sudan, which had different soil depth intervals (0–0.3 m, 0.3–0.6 m, 0.6–0.9 m, 0.9–1.5 m, and >1.5 m) from Entisols in the Northern State of Sudan. The data were stratified into homogeneous groups based on the textural classes of the main soil order. Then, regression models were performed and evaluated using the coefficient of determination ( R2), standard error of the estimate (SEE), and root mean square error (RMSE). The results indicated that in individual Entisols and textural classes, the combined soil covariates silt, clay, and SP were the best properties to predict CEC values ( R2 ranged from 0.86 to 0.99). The regression models did not provide statistically significant results for the silty clay loam textural class ( R2 ranged from 0.01 and 0.35). The findings of this modeling study could be applied to other Entisols worldwide with divergent textural classes, which could be used to verify the suggested CEC pedotransfer functions and/or improve them. This would help farmers correctly design soil management plans and prevent acidification issues if combined with other soil properties data.

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“…Dioctahedral vermiculite is more common than trioctahedral vermiculite in soils (Jackson, 1959;Rich, 1960). Trioctahedral vermiculite may comprise a significant amount of the sand and silt fractions of soils (Alexiades et al, 1973;Coffman and Fanning, 1974), whereas dioctahedral vermiculite is seldom observed as discrete crystallite >5 f-Lm (Douglas, 1977). Mediumsized silt fractions may contain muscovite-dioctahedral vermiculite interstratified minerals.…”

Section: Vermiculitementioning

confidence: 99%