摘要
Forty five soil samples were collected from the four pedons of the hill areas at Chittagong University based on the depth of soil horizon. Soil profiles on hill top were relatively well developed and belonged to Ultisols according to USDA soil Taxonomy. The profiles at the piedmont were relatively young soils and classified as Inceptisols and Entisols. The soils of all profiles were characterized by coarse texture (38% to 73%, sand fraction), high bulk density (1.15 to 1.32 Mg·m-3), low organic-C content (0.26% to 1.73%), acid soil reaction ( varied from 4.44 to 5.52 and pHKCl from 3.57 to 4.90). Soils in all pedons were poor in exchangeable bases and base saturation. The CEC values ranged from 9.12 cmolc·kg-1 to 14.5 cmolc·kg-1 while ECEC varied from 1.96 to 4.78 cmolc·kg-1. The exchangeable Al (aluminum) concentration ranged from 0.41 to 0.66 cmolc·kg-1. Exchangeable acidity level ranged from 0.74 to 1.25 cmolc·kg-1. Exchangeable Al and aluminum saturation increased with depth and their concentrations were below the toxic range for tree stands. The study revealed that more young soils formed on the piedmont sites had somewhat better properties as compared to matured hill top soils. The variation in physico-chemical properties of the soils seemed to be influenced by the topography to a greater extent in the studied area.
Forty five soil samples were collected from the four pedons of the hill areas at Chittagong University based on the depth of soil horizon. Soil profiles on hill top were relatively well developed and belonged to Ultisols according to USDA soil Taxonomy. The profiles at the piedmont were relatively young soils and classified as Inceptisols and Entisols. The soils of all profiles were characterized by coarse texture (38% to 73%, sand fraction), high bulk density (1.15 to 1.32 Mg·m-3), low organic-C content (0.26% to 1.73%), acid soil reaction ( varied from 4.44 to 5.52 and pHKCl from 3.57 to 4.90). Soils in all pedons were poor in exchangeable bases and base saturation. The CEC values ranged from 9.12 cmolc·kg-1 to 14.5 cmolc·kg-1 while ECEC varied from 1.96 to 4.78 cmolc·kg-1. The exchangeable Al (aluminum) concentration ranged from 0.41 to 0.66 cmolc·kg-1. Exchangeable acidity level ranged from 0.74 to 1.25 cmolc·kg-1. Exchangeable Al and aluminum saturation increased with depth and their concentrations were below the toxic range for tree stands. The study revealed that more young soils formed on the piedmont sites had somewhat better properties as compared to matured hill top soils. The variation in physico-chemical properties of the soils seemed to be influenced by the topography to a greater extent in the studied area.
