Characterization, Classification, And Evaluation Of Soils Of Four Geomorphic Surfaces In Oguta Imo State Southeastern Nigeria

ABSTRACT

This research was carried out to characterize, classify, and evaluate soils of four geomorphic units in Oguta Imo State Southeastern Nigeria. Four Pedons, each was located in each geomorphic unit. ] soil sampling was carried out in the study site, sixteen surface soil samples (0-20 cm) were collected, four from each of the geomorphic units using an auger giving a total of thirty three soil samples which was chosen to represent the main morphological variations and to present mapping units throughout the soils of Oguta Imo state Southeastern Nigeria. Results of the laboratory analysis showed that the soils were predominantly sandy loam and loamy sand. Texture was coarser at the terrace than the levees and backswamp. The soils in the levee crest, were classified into subgroup Typic Eutrudepts, levee slope and terrace Typic Hapludults while soils of backswamp were classified as Typic Endoaquepts. The soils were classified into land capability class II, III, IV and V with limitations due to nutrient holding capacity (n), wetness, (w) and angle of slope (a). The results of the land suitability classification for wetland rice production showed low suitability (S3) for all the soils. Land suitability classification for cassava production showed moderate or medium suitability (S2) for the soils of levee crest, levee slope and terrace, while the soil of backswamp has low suitability (S3). However, soils of levee crest – backswamp (EO1EO4), levee crest surface soils - terrace surface (EO1S-EO3S) showed moderate or medium suitability (S2) for maize production while backswamp surface soils (EO4S) showed low suitability for maize production. Land suitability classification for Sugarcane production showed moderate/medium suitability (S2) for all the soils in the studied geomorphic units. Data generated from various analyses were subjected to analysis of variance (ANOVA). Correlation analysis was used to estimate degree of relationship among soil properties. The results of fertility capability classification (FCC) showed uniform loamy top and subsoil. The major limitations of the soils for crop production are soil texture and structure, which directly affect waterholding capacity, permeability of the soil among other soil physical properties.