EFFECT OF SLOPE CHARACTERISTICS ON AGGREGATE-SIZE DISTRIBUTION IN SOILS FORMED ON COASTAL PLAIN SANDS IN AKWA IBOM STATE, NIGERIA
Essien, O. A. & Ogban, P. I.
Department of Soil Science and Land Resources Management
Faculty of Agriculture University of Uyo, Uyo, Akwa Ibom State, Nigeria
Corresponding Author: otobongessien19@yahoo.com
ABSTRACT
Investigation of slope characteristics influence on aggregate size distribution is necessary in guiding management practices of the soils formed on coastal plain sands, in Akwa Ibom State. Effect of slope characteristics on aggregate size distribution were examined in coastal plain sands in Akwa Ibom State, Nigeria. Five soil samples were collected at 20m interval from each of twelve selected similar slopes / location, based on their form and length. A total of sixty samples were collected and analyzed in the laboratory for physical and chemical properties. Each of the 60 soil samples were separated into four aggregate size fractions; 4-2.0mm, 2.0-0.25mm, 0.25-0.05mm and <0.05mm, using the dry and wet sieving methods. The data generated were analyzed in terms of slope aspect, slope curvature and slope gradient effect on aggregate size distribution. The result shows that the physical and chemical properties of the soils in the study area were affected by slope aspect, curvature and gradient by causing redistribution of soil properties along the slope. Slope aspect significantly (P< 0.05) affected dry aggregate size distribution with the highest mean value of 4.01mm for the < 0.05mm diameter, occurring on the south facing slope was 3.1mm. slope gradient significantly (P< 0.05) affected < 0.05mm dry aggregate size fraction with the highest mean value of 4.35mm occurring on the <10% slope followed by >20% with 3.52mm and 11-20% with 2.80mm/. Understanding the effect of slope characteristics can guide in selecting suitable management practices of the soil.
Keywords: Slope aspect, slope curvature, slope gradient, aggregate-size distribution, soil physical properties, soil chemical properties, coastal plain sands
