Landscape-soil relationship on a transect in central Assam

Eight pedons representing major soils in a varying physiographic stretch, across the central Assam were studied for their characteristics and classification. The soils are derived from sedimentary and metamorphk parent materials grading from the most ancient to the recent. Field morphology, physical and chemical properties show variation in pedogenic development of the soils with respect to their geology and physiographic position. These soils, classified according to USDA Soil Taxonomy are Udalfs, Udifluvents, Udorthents, Epiaquepts, Eutrochrepts, Dystrochreptsind Udults. Udults are found to occur on a relatively stable moderately steep and moderately dissected landscape in Mikir hills of Karbi Anglong. Dystrochrepts are the major soils in association with Udorthents on strongly sloping highly dissected landscape. Association of Dystrochrepts and Eutrochrepts are found to occur on undulating uplands. Epiaquept and Udifluvent are the dominant soils on gently sloping plain and active flood plain, respectively. Soils are, in general, acidic with low to medium cation exchange capacity.