Variations in Soil Physical Properties Along Toposequence of an Alfisol in Southern Guinea Savanna of Nigeria

Relationship between slope position and soil physical properties was studied. Profile pits, each was dug at three topographic positions identified in the area, upland, middle and valley bottom. Samples collected were analyzed for saturated hydraulic conductivity (Ks), permeability, field capacity, bulk density, porosity, and soil texture. A significant decrease in clay content down slope was the major factor influencing the changes associated with soil physical properties. The middle slope showed the highest clay content (12.90%) and lower slope the lowest (4.87%). Ks decreased significantly down slope showing poor soil drainage lowest (2.25 cm/hr) and highest (6.85 cm/hr) at D3 and aeration in depths of the upland. Bulk density had significant difference in D1 and D2 on the middle slope but had the highest value 1.88 g/cm3 and least 1.23 g/cm3. The trend of change and difference in soil physical properties across the slope shows that it differs at the three slope positions.. The major pedogenic process observed to influence the relationship between slope position and soil properties were mineral weathering, erosion and eluviations – illuviation processes.