Available forms of iron in soils can be assessed through the use of chemical extraction methods. Soil test provide an indication of nutrient level in the soil and together with plant analysis are important agronomic tools for determining crop nutrient needs, predicting the nutrient-deficient areas and preventing the deficiency. This study was therefore conducted in laboratory and greenhouse environment to evaluate suitable extraction method for predicting available forms of iron in soils of southeastern Nigeria, using five extraction procedures (Coca-cola, 0.05M EDTA, 1N NH₄OA_C +0.05M EDTA, 1N NH₄OA_C and O.1N HCl). Iron uptake by maize (Zea mays L.) plants was analyzed together with the Fe content in the soils in which maize plants were grown under greenhouse conditions. Iron content in maize plants were determined by AAS. The results obtained in this study shows that Coca-cola method extracted the highest amount of the Fe (12.77 mgkg^-1) while, 1N NH₄OA_C +0.05M EDTA extracted the least amount of Fe (4.48 mgkg^-1) with an average of 7.33 mgkg^-1. Coca-cola-extractable Fe correlated positively and significantly with Fe concentration (r = 0.650**) and Fe uptake (r = 0.712***) while, O.1N HCl- and 0.05M EDTA-extractable Fe had significant positive correlations with dry matter yield and Fe uptake. Their r values being, (0.630** and 0.676**) and (0.601** and 0.588*), respectively. Moreover, the result obtained from the regression equations corresponded with the correlations values determined. Accordingly, the study indicates that, the order of significance for the extracting solutions is as follows: Coca-cola > O.1N HCl > 0.05M EDTA > 1N NH₄OA_C > 0.05M EDTA+1N NH₄OAc. Thus, the high correlations (r) values of extractable Fe with soil properties and yield parameters suggests the superiority of Coca-cola, O.1N HCl and 0.05M EDTA extractants over others extractants but, the Coca-cola method was determined to be the most suitable extractant for predicting available Fe content for soils of southeastern Nigeria. However, in the absent of Coca-cola extractant, HCl and EDTA methods can equally be used in the determination of available Fe in these soils.

Keywords: Acid, Acid sands, Chelate, Ex tractants, Fe uptake, Iron, Maize, Salt