Horizon Differences in Micronutrient Contents of Soils of the Coastal Plain Sands in Imo State, South - East Nigeria

Horizon differences in soils influence ability of crops to obtain nutrients and indeed support other uses. The study aimed at investigating the micronutrient (Cu, Mn, Fe, Zn) contents of horizons of two different pedons which lies on similar parent material (Coastal plain sand) in Imo State. Random survey technique guided by the geologic map of the area was used in siting one profile pits on each of the locations. The profile pits were described; and identification and delineation of horizon boundaries were accomplished using FAO guidelines before actual sample collection for laboratory analyses. Soil data were subjected to coefficient of variation (CV) analysis. The results of the micronutrients indicated range values of 0.02- 0.36 mg kg-1 for Mn, 36.6-108 mg kg-1 for Fe, 0.091-0.256 mg kg-1 for Cu and 0.205-0.774 mg kg-1 for Zn in pedon 1. In pedon 2, the ranges were 0.13-1.09 mg kg-1 for Mn, 19-50.6 mg kg-1for Fe, 0.143-0.613 mg kg-1 for Cu and 0.22- 0.962 mg kg-1 for Zn respectively. The values of Zn, Cu and Mn were below the critical limits recommended for arable crop production. However, Fe concentration was generally high in all the horizons and was above the critical level recommended. Hence, the soils were surplus in iron but deficient in Cu, Mn and Zn. It is therefore recommended that agronomic requirements should consider these essential edaphic attributes in the study area.