抄録
Smectites separated from three soils of Ganges Floodplain, Bangladesh, were characterized. The smectites content in the fine clay fractions was in a range of 62 and 88%. Expansion to 1.8 nm by the Greene-Kelly test and the (060) spacingaround 0.150 nm suggested that the smectites were mainly beidellite-type. Elemental composition calculated from total chemical analysis showed that the smectites had layer-charge of tetrahedral-origin and were rich in Fe. The structural formula for the smectites of Silty Ganges Alluvium, which is hardly subjected to decalcification, was estimated as (Si6.90Al1.10)(Al2.46Fe0.99Mg0.76) O20 (OH) 4X1.25. The impact of iron-rich beidellite on the soil fertility potential was discussed.
