Bentonite as an Ameliorant in an Alfisol—A Laboratory Study

Bentonite, a commercially available clay mineral, can be used for increasing the water holding capacity of the soil and as a sealant material. Laboratory studies were conducted with the amended soil using bentonite as an ameliorant. The mixtures were prepared with the additives on a volume basis. The chemical, physical, and hydraulic properties of the bentonite and native red soil (alfisol) mixtures were determined. Available water contents improved significantly in soil-bentonite mixtures. The pH of bentonite and soil mixtures increased from neutral value to alkalinity with the increasing proportion of bentonite in the mixtures. The same trend was also observed for cation exchange capacity. Bulk density increased from a 1:50 mixture to a 1:5 mixture and afterward decreased with the increase in the proportion of bentonite. Plastic and flow limits of the mixtures increased with the increase in bentonite proportion. Soil erodibility (dispersion ratio) as well as surface cracking increased with the addition of bentonite to native soil.