Soil mapping, classification and morphological characteristics of the University of Benin land

Abstract

This study was conducted to map, and classify the soils of University of Benin Teaching, Research and Integrated Farm site. Rigid grid soil survey method at an intensive scale was done on a 62-hectare land that produced seven mapping units. In each mapping unit, a representative pedon was sunk, described and sampled. Soil samples were analyzed using standard methods. Data generated were analyzed using descriptive statistics to determine their coefficient of variation. The r esult indicated that the soils were reddish when moist at different contrasting levels. Textural classes ranged from Loamy sand to Sandy Clay Loam while structure ranged from Single grain crumb to Sub-angular blocky. The pedons were well drained except for pedon 5, which had mottles at subsurface horizon. Means of Sand fraction ranged from ≤649 to ≥ 931 gkg-1 ; Silt ranged from ≤13.2 to ≥ 47.7gkg-1 while Clay ranged from≤ 50 to ≥ 303 gkg-1 in all the pedons; clay fraction increased with increase in depth, forming argillic horizon in pedons 1,2 and 7. pH had means ranging from ≤4.23 to ≥5.28 and recorded low variation (≤ 3.6 to ≥ 13.0 %) in all the pedons. organic carbon had means ranging from ≤ 3.3 to ≥ 36.4 gkg-1; CEC ranged from ≤ 4.85 to ≥ 16.4 cmolkg-1 while Base saturation ranged from ≤16.6 to ≥ 51%. Hence pedons 1, 2 and 7 were placed in the order Ultisols ( Acrisols); pedons 3and 4 in Entisols ( Arenosols) Pedon 4; Pedons 5and 6 in Inceptisols (Cambisols) according to USDA Soil Taxonomy and correlated with WRB.