Sedimentological and Physicochemical Properties of Sediments from Oblaruku and Environ, Southwest Nigeria

Abstract

Sedimentological and some physicochemical analyses were carried out on soil samples within Obiaruku and environs in order to establish baseline conditions for  the purpose of basic development projects. The results show that the sediments were of medium grade, poorly to moderately sorted and finely to strongly coarse skewed with a leptokurtic to platykurtic kurtosis. Effective cation exchange capacity and carbon content was generally low ranging between 8.68-17.88ppm and O. 70-3.05% respectively. Phosphorus contents ranged from 0.40-1.04% and 0.20-1.20% for surface and subsurface soils respectively. Phosphorus availability in the soil was observed to be influenced by the soil pH, potassium, and Effective cation exchange capacity. Similarly, Nitrate content ranged from 0.03-0.14% and 0.02-0.09% for surface and subsurface soils respectively. The availability of nitrogen in the soil was influenced by the presence of potassium only among the parameters tested. Phosphate and nitrate content in the soils also decreased with depth. Changes in soil  chemistry were related to natural variations in grain size, organic matter content and geologic substrate. Within the subsurface, the study area shows a fairly low nutrient concentration as against 0.02% in natural soils to 0.15% in cultivated soils for nitrogen, and less than 1.5% in soils for available phosphorus.