Plants, such as bahiagrass have the ability to actually absorb iron through the leaf tissue as opposed to having to be taken up through the roots. Iron can also be applied to the ground as either iron sulfate or as a chelated iron. If cost is a concern, iron sulfate is by far cheaper than chelated iron. When iron is applied to the ground in the form of iron sulfate, a large percentage of it immediately gets tied up in chemical forms unavailable to the plant root. For this reason chelated iron was developed.
Chelated iron is much more available to plant roots.
However, this form of iron is most likely cost prohibitive for pastures. We have conducted research and demonstration studies at the Ona AREC on iron fertilization of bahiagrass. Preliminary data indicates that iron deficiencies first become noticeable in the spring. This is a result of the fast growth of bahiagrass causing an iron deficiency due to a dilution effect in the plant. Our studies have shown that when iron is foliarly applied or applied to the field as either iron sulfate or chelated iron that the yellowing in the grass disappears in a matter of a few weeks, however there does not appear to be any benefits in yield with the addition of iron.