Nitrogen is still the #1 nutrient when it comes to Corn. But it is joined by several other nutrients and secondary nutrients. With the wet and rainy weather we have been having this Spring, we are bound to have nutrient deficiencies in our fields. Below are 7 key corn nutrient deficiencies and a description of what each one will look like out in your field.
1. Nitrogen- Nitrogen is a mobile nutrient. In younger plants, plants will be stunted with light green or yellowish green color. In older plants, v shaped yellowing will start on the leaf tip and work its way down the plant on the older leaves.
2. Phosphorus- Phosphorus is a mobile nutrient. When the soils are cold and wet, or dry and compacted this can limit the amount of phosphorus the roots can pick up, producing a deficiency in the plant. Early signs of phosphorus deficiency include stunted, dark green to bluish green plants with purpling or reddening of the tips and leaf margins on the older leaves.
3. Potassium- Potassium is a immobile nutrient. This deficiencies will appear on the lower leaves, beginning at the tip of the leaf and running down the margin. The plant may wilt easily, especially in full sunlight.
4. Sulfur- Plants deficient in sulfur will be stunted, spindly and light green in color. The upper leaves will become light green first and interveinal yellowing or leaf striping is the key symptom of sulfur.
5. Magnesium- Magnesium symptoms will appear when plants are in sandy, acidic soils where high rainfall has happened. Look for yellow to white interveinal striping on young plants. Round, dead spots may appear on the leaves. The older leaves become reddish purple.
6. Manganese- When corn plants have a manganese deficiency, leaves will have a light- green or olive green color with slight yellowish stripe on the upper leaves. Manganese deficiency is most common where manganese soil test levels are low and soil pH was high.
7. Zinc- Low soil levels combined with high pH will produce zinc deficiency. Zinc deficiency will appear in cool, wet soils with low organic matter, when its cloudy early in the season and soil compaction will affect the corn roots. Symptoms are white, interveinal strips extending from the leaf base to the leaf tips. The leaf edges, tips, and midrib will stay green in color.
