Darryl Warncke
Crop & Soil Sciences

There have been a number of reports of nutrient deficiencies in corn. Many of these are likely the result of the cool, wet soil conditions that the young corn plants have experienced. These conditions have resulted in slow root growth which results in limited nutrient uptake. Purple coloration of the leaves is frequently associated with inadequate phosphorus uptake. This is more likely to occur on clayey soils, poorly drained fields or in no-till fields with lots of residue that warm up more slowly. Band application of phosphorus at planting helps prevent this from occurring. Yellow stripping of the youngest leaves has been observed on low organic matter sandy soils. This is most likely related to inadequate uptake of sulfur. As the soil warms and the roots reach into the subsoil where there is more sulfur, the plants will grow out of the deficiency. Some yellowish mottling or stripping of the older leaves sometimes accompanied by a little reddish discoloration is frequently associated with magnesium deficiency. This is most likely to occur on sandy soils, especially if the pH is less than 6.0. Unless these deficiencies are severe, the corn will grow out of it as root growth improves. Foliar application of 2 lb sulfate-S/a or 2 lb Mg/a will help alleviate the shortage of sulfur or magnesium, respectively.