Yellow Corn

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By Dairyland Seed Agronomy Team

The yellow and striped corn we are observing this spring could have several causes.

The first possibility, and perhaps everyone’s knee jerk reaction, is nitrogen deficiency. Deficiency doesn’t mean there isn’t enough nitrogen applied. It may just be out of “reach” of the young roots at this time. Most of the yellow and striped corn we have dealt with is on lighter textured soils. So, we could be experiencing some leaching just beyond where the roots are growing. However, most areas are dry except for our more southern geographies. The other scenario is that our side-dress application hasn’t been applied yet, and the plants are growing faster than nitrogen can be supplied.
The second possible reason for yellow corn is the weather has finally become favorable for rapid vegetative growth. The yet developing permanent root system can’t keep up supplying the nitrogen, sulfur and zinc needs of the quick growing plant. As a result, we see the tell-tale signs of yellow corn.
The next reason for yellow striped corn, especially on lighter soils, can be sulfur deficiency. Sulphur is mobile in the soil much like nitrogen. Heavy rains in the spring can move this nutrient out of contact with the young root system. For most of the Dairyland Seed marketing area, this was not the case. There were a few general areas that did get heavy rain, and it seems to be more prevalent there. The cool conditions restricting root growth in late April/early May kept the plants from accessing what sulfur was available.
Yet another possible cause has been zinc deficiency. Zinc deficiency will have the yellow stripe sin addition to a whitish color toward the base and mid rib of the leaf. All three nutrient deficiencies will look similar with interveinal chlorosis and striping at some point in time. Factors that may encourage zinc deficiency include high pH, very high phosphorus levels, sandy light texture and high organic matter soil. Weather conditions favoring zinc deficiency are typically cool and wet with limited sun. We certainly had cool in most cases but perhaps not as much wet.

In most situations, more ideal growing conditions should alleviate the symptoms. In others, the completion of side dress operations, in combination with growing conditions, will snap plants into shape. In many areas, the addition of sulfur or zinc may be warranted. If this is the case, a pretty standard practice is about 20 pounds of sulfur and 15 to 30 pounds of zinc sulphate. Another consideration may be the addition of micro nutrient as a foliar feed especially if it can be added to your post emergent herbicide application.

If you have further questions or concerns, feel free to contact your local Dairyland Seed Agronomist.