Characterization and Classification of Clay Rich Alluvial Soils to Explore Soil-Landform Relationship in Lower Indo-Gangetic Plains of India

Abstract

Characterization and classification of soils divulge its genesis and processes of formation, which
is strongly related to geomorphic cycles followed by landform development. The alluvial plains are complex
landscape assemblages formed by the overlap of multiple riverine systems. Soils developed under alluvial
plains are having wide variations depicting the partial influence of different rivers and the quality and
quantity of sediments, spatially and temporally. To investigate the characterization, genesis and classification
of alluvial soils with its subsequent spatial occurrence in the Lower Indo-Gangetic Plains of West Bengal,
the present study has been carried out in Habibpur block of Maldah district, West Bengal situated within
Tangon and Punarbhaba river plains under two contrasting landform situations (old alluvial plains and
young alluvial plains) with varying slope classes. Soils of old alluvial plains were very deep, moderately well
drained, slight to moderate erosion with having clay enrichment (presence of argillic horizon) in the sub-soil
layers and classified as Alfisols. Inceptisols with very deep, well to somewhat poorly drained soils were
found under young alluvial plains. In general, the pH, soil organic carbon and cation exchange capacity of
the surface horizon ranged from 5.7 to 6.6, 0.3 to 0.9 % and 6.3 to 15.1 cmol (p+) kg-1, respectively. Data on
pedogenic indices revealed that, the P1 and P2 pedons of old alluvial plain and P4 pedon of the young
alluvial plains had relatively lower sand/silt ratio as compared to the P3 pedon of young alluvial plains
(nearly level) in both surface and sub-surface horizons showing the more matured soils with relatively higher
profile development in P1, P2 and P4 pedons than P3 pedon. The distance and influence of the river on soil
devepoment has been found to be very crucial and could dominate over the other soil forming factors active
in alluvial plains.