Pedogenesis of Some Hydromorphic Soils of Upper Brahmaputra Valley Region, Assam, India

Abstract

Hydromorphic soils and their properties are key to address various issues of the waterlogged regions related to its productivity and conservation. The present investigation is aimed to investigate the pedogenesis of some hydromorphic soils of the Upper Brahmaputra valley region of Assam. Six pedons from North West Jorhat Development block were selected and examined for the purpose. Detail morphological, physical and chemical characteristics of the hydromorphic soils under different landforms and land uses were done through land resource inventorization (at 1:10000 scale) using and fine resolution satellite image. The study showed change in soil characteristics with micro-topographic variation. Wide variability in particle size is attributed to frequent occurrence of lithologically discontinued soil horizons in active flood plains due to fluvial processes and changes in the course of Brahmaputra river. Soils were characterized by strongly acidic (pH 4.74) to neutral (pH 6.7) in soil reaction, low (0.48%) to high (1.14%) in organic carbon, low [3.13 cmol (p+) kg - 1] to medium [11.90 cmol (p+) kg - 1] in CEC and low (26%) to high (71%) in base saturation status. Active flood plains were endowed with Typic Endoaquents, whereas in the younger and older flood plains, soils formed were Fluventic Endoaquepts and Typic Endoaqualfs, respectively. The vertical distribution of different pedogenic indices were computed and discussed.