Variability in Selected Soil Properties of Soils of Dissimilar Parent Materials in the Humid Tropics

The study investigated variability of selected soil properties of soils derived from different parent materials (that is false bedded sandstone and Imo clay shale) in the humid tropic. Soil samples were collected from horizons based on profile differentiation. Data collected were subjected to statistical analysis using coefficient of variation (CV) and correlation. There were variations in soil properties of the two studied areas. Results showed that soil properties differed in their degree of variation among the parent materials. Sand content had little variation in both soils (CV = 6.56 % and CV = 17.23 %) for false bedded sandstone and Imo clay shale respectively. Clay had moderate variation in both soils (CV =40.17% and 36.50 %) for false bedded sand stone and Imo clay shale respectively. Bulk density and pH had little variation in both soils CV =7.30 % and CV =4.29) in false bedded sandstone while (CV =6.16 % and 4.85 %) in Imo clay shale. Organic matter varied highly in false bedded sandstone (CV =51.32 %) while in Imo clay shale it varied moderately (CV = 42.30 %). Organic matter had positive significant relationship with clay content in both soils (r =0.98, 0.99, P < 0.05) for false bedded sandstone and Imo clay shale respectively. pH had a negative relationship with Available phosphorus in false bedded sandstone (r =- 0.45, P < 0.05) while in Imo clay shale pH had positive significant relationship with Available phosphorus ( r =0.96, P< 0.05). pH had non- significant positive relationship with organic matter in both soils (r = 0.63, 0.06, p < 0.05) for false bedded sandstone and Imo clay shale respectively. A more intensive soil sampling from the study area with the inclusion of more parameters will provide a better and reliable representation of the variability of soil properties even at a regional scale.