ASSESSMENT OF SOME MICRONUTRIENTS IN PROFILES OF TYPIC PLINTHUSTALFS IN MINNA, SOUTHERN GUINEA SAVANNA, NIGERIA

Abstract

A study was carried out to assess the distribution and relationship of some micronutrients in profiles of Typic Plinthustalfs, the dominant soil unit in the Teaching and Research Farm of the Federal University of Technology, Minna, Nigeria. Two related soil profiles designated as NM-1 and NM-2 respectively were evaluated for their copper (Cu), zinc (Zn), iron (Fe) and manganese (Mn) contents. Also, the relationship of these micronutrients with sand, silt, clay, pH and organic carbon (C) were determined. The two soil profiles had surface texture of sandy loam with subsurface characterized by presence of concretionary layers. The pH of the soil was rated strongly acid to moderately acid in both profiles. Organic C and available phosphorus (P) were low in both pedons while total nitrogen was rated high except in the C-horizons. Calcium (Ca) was low in the surface horizons and high in the subsurface of NM-2. Magnesium (Mg) and sodium (Na) were rated medium to high while potassium (K) was high irrespective of horizons in both profiles. All the micronutrients were sufficient in the soil for crops. Only Zn correlated significantly (P < 0.01) with organic carbon (r = -0.81). The relationships of other micronutrients with texture, pH and organic C were not significant. For adequate supply of essential micronutrients, the soil may require liming to raise the pH to favourable range for optimal availability of micronutrients. Incorporation of organic residues is required to improve the soil organic C and structure induced by the plinthites.