Study of the soils of Deepor beel catchment in relation to soil forming factors using remote sensing and GIS

摘要

In order to understand the effect of physiographic features, parent material and slope on soil genesis, a detailed investigation was carried out in the soils of deepor Beel catchment. Eight pedons representing alluvial plain on level to gently slope,highly dissected residual hills on grainitic gneiss with moderately steep slope, moderately dissected hills on Grey Porphyritic Granite and ganitic gness with moderately dissected hills on grey porphyritic granite and granitic gneiss with moderately sloping to moderately steep slope and piedmont area were studied in detail. Soils developed on highly dissected residual hills and moderately dissected hill on granite gneiss are well developed, deep to very deep, well drained, red in color and clay in texture throughout the profile. The soil of hilly region of the study area is Alfisol with udic moisture regime. Alfisols with aquic and udic moisture regime and Inceptisols with aquic moisture regime are found in alluvial plains. About 62.2% area of alluvialplains is Alfisols which is developed in the very gently (1-3%) to gently sloping (3-8%) foot hills. The soils are very deep, dark reddish brown to reddish yellow in colour, sandy clay texture in surface horizon and clay in subsurface horizons. Preseceof mottles in different horizons indicates that the soils are poorly drained. In the alluvial plain, 1361 ha area in Inceptisols that are developed on recent alluvium with level to nearly level slope (0-1%). The soil of the surface horizon is pale brown,and lower horizons are gray in colour. The soil texture is clay throughout the profile except the lower most horizons which is sandy clay. The soils is poorly drained and saturated with water for a longer period which results in presence of mottles in different horizon of the profiles. Dense forests are found in highly dissected hilly areas. Paddy cultivation is found in the alluvial whereas open forest and scrubs are found in the moderately dissected hills. The soil map units of the study area were grouped into 3 land capability classes (i.e. III, IV and VI) and 7 sub classes. The study shows that maximum area (i.e. 71%) of the catchment is under capability class IV whereas Class III and class VI occupies 20% and 9% of the study area respectively. The major limitation of the study area is topography, wetness and soil texture.