USDA classification and clay and sand mineralogy of the studied soils C, chlorite; F, feldspar; I, illite; Q, quartz; S, smectite; P, palygorskite Soil order USDA classification Clay Silt mineralogy mineralogy Alfisols Fine,
smectitic, mesic, S >> I Q > S > Typic Haploxeralfs F = I = C Vertisols Fine,
smectitic, mesic, S >> C > Q >> S > Typic Haploxererts I = Q I = C = F Aridisols Coarse-loamy, carbonatic, S > C = I Q >> S = thermic, Typic > P > Q I = C > F Haplocalcids Entisols Coarse-loamy, carbonatic, S = P > Q > S = F = hyperthermic, Aridic I > C I = C Ustorthents Table 3.
The predominant soils on this site are Aksarben silty loam (fine,
smectitic, mesic Typic Argiudolls; USDA, 2017).
The field experiment was conducted in 2014 and 2015 on a Dewitt silt-loam soil (Fine,
smectitic, thermic Typic Albaqualfs) at the Rice Research and Extension Center near Stuttgart, AR.
Identification of mineralogical components of
smectitic type was carried out applying the protocol established by Thorez [36] and Schultz [37].
All these grains exhibit anhedral and angular morphologies and they are included in a fine-grained matrix made of angular calcite grains and interstitial clay minerals of
smectitic composition (Fig.
Shoval (2004) studied the marine sedimentation along the margin of the southeastern Neo-Tethys, and concluded that Senonian and the Eocene is dominated by
smectitic IS (mixed-layer illite/smectite rich in smectite layers) accompanied by kaolinite, palygorskite and occasional sepiolite.
Chakroun et al., "Lead removal from aqueous solutions by a Tunisian
smectitic clay," Journal of Hazardous Materials, vol.
Smectitic clays, such as bentonites, are the most widely used in peloid therapy, because of their high specific surface area, ion exchange properties, plasticity, expansibility, absorbing capacity and spreadability.
Of the four types of clay minerals, montmorillonite is a
smectitic (expanding) clay.