We continue to get a few calls regarding Localized Decline, perhaps more this year than the last couple. The field shown at right had about 7 to 8 pounds of actual zinc per acre applied to it when the problem showed up. Apparently, that is not enough in this field. Dr. Harrell’s studies have shown that about 10 pounds of actual zinc as zinc sulfate or 2 pounds as zinc chelate are necessary to correct the problem. In severe cases more is needed.
What confused me when I visited the field were the conspicuous green drill rows in contrast to the affected plants. The farmer told me all of the green rows are where there was an excessive amount of seed as a consequence of a malfunction of the planter not detected until much of the field had been planted. This could provide another clue. Plants showing the symptoms almost always have very high levels of iron and aluminum in them. It could be a dilution effect of the toxic elements because each seedling is getting a lower dose of these elements.