The consequences of micronutrient deficiency or toxicity for the agricultural productivity in the state of Rio de Janeiro are not adequately known. For this reason, in 1997, the levels of copper, zinc, iron, and manganese were quantified in 103 samples from surface horizons of representative soils of the state. The extractant solutions used were Mehlich-1, DTPA-TEA, and HCl 0.1 mol L-1. In general, the HCl 0.1 mol L-1 solution extracted the highest amounts of the studied micronutrients. Mehlich-1 extracted the smallest amounts of copper and iron, and the DTPA-TEA extracted the smallest amounts of zinc and manganese. The results showed that the use of linear regression equations for conversion of values amongst methods of a specific element and the use of ranges of interpretation developed in different edaphic conditions, in comparison to the present work, are not recommended. They can lead to incorrect diagnoses.
micronutrients; soil fertility; extractant solution