Ferric ethylenediamine di (o‐hydroxyphenylacetic acid) (FeEDDHA) when used on calcareous soil can induce low Mn levels in plants. The effect can be overcome by Mn or ethylenediamihe tetraacetate (EDTA) applications and seems to be related to interference with Mn absorption by FeEDDHA at pH levels over 7. Low levels of FeEDDHA effectively overcome Fe deficiency in calcareous soils without causing decreases in the Mn levels in plants. The implications are that two procedures for avoiding Mn deficiency are adding Mn with FeEDDHA treatments and/or using relatively low levels of FeEDDHA for treatment of plants with Fe deficiency.