Characterization and Classification of Soils Derived from Two Different Parent Materials in Niger State, Nigeria

The aim of this study was to characterize and classify soils developed under two different parent materials (that is, basement complex rocks and the sedimentary rocks) in Niger State. Four sites, two each under the formations were selected for the study. Gidan Mangoro (GDM) and Nubwa Koyi (NBK) represented the basement complex while Patita (PTA) and Ndayako (NDY) represented the sedimentary rocks. In each site, a mini profile pit (1m x 1m x 1m) was dug, described and sampled according to FAO guidelines. The samples were analyzed in the laboratory following the standard analytical procedures. The soils were classified according to USDA Soil Taxonomy system and correlated with the WRB System. The texture of GDM, was loamy sand at topmost horizon (Ap), underlain by sandy clay loam at Bt horizon over sandy loam texture at Btv horizon. The NBK was sandy loam at Ap horizon over sandy clay loam at Btv1 and Btv2 horizons. PTA, and NYK were sandy loam all through. Soil pH was moderately acid to neutral in all the study sites. Total nitrogen was low (0.3 g kg-1), (> available phosphorus was moderate to high (9.33 to 29 mg/kg-1) Exchangeable potassium (K) was low to very low (0.05 to 0.11 cmol kg-1), while cation exchange capacity (CEC) ranged from 5.02 to 10.40 cmol kg-1 and was low to moderate. The soils were classified as Typic Plinthustalf (GDM),Plinthic Kanhaplustult (NBK), Oxic Haplustept (PTA) and Rhodic Kanhaplustults (NDY). The soils developed under basement complex rocks were shallow to deep soils while the soils from sedimentary rocks formations were deep to very deep.