What Is a Maize Zinc Deficiency Called?
While there is no single formal scientific name, the most severe form of a maize zinc deficiency is commonly referred to by growers as 'white bud'. This descriptive name directly reflects the most striking symptom: the youngest, newest leaves emerge from the whorl with a pale yellow to white coloration. While 'white bud' is the term for severe cases, the broader condition is simply known as zinc deficiency in maize, and it is characterized by a range of visual symptoms that worsen with severity.
Symptoms of Maize Zinc Deficiency
Recognizing the signs of a zinc deficiency is the first step toward corrective action. Symptoms can vary depending on the severity and the maize's growth stage.
Early-Stage Symptoms (Seedling Stage)
- White Bud: The most severe symptom, where the youngest leaves turn white or pale yellow.
- Interveinal Chlorosis: The area between the veins of the youngest leaves becomes pale or yellow, often appearing as longitudinal stripes or bands.
- Stunted Growth: Limited internode growth results in a short, squat plant appearance.
Later-Stage Symptoms
- Stunting Continues: The overall growth of the plant remains inhibited, and new leaves continue to exhibit chlorosis.
- Leaf Discoloration: In severe, advanced cases, leaf margins may develop a reddish-brown or necrotic (dead tissue) discoloration.
- Delayed Development: The maize plant's flowering and ear development can be significantly delayed or hampered.
Factors Contributing to Maize Zinc Deficiency
Several environmental and soil conditions can exacerbate or trigger a zinc deficiency, even if the soil contains some zinc.
- High Soil pH: Alkaline soils limit the availability of zinc to the plant, as it becomes less soluble and more tightly bound to soil particles.
- Cold, Wet Soil: Cool and saturated soil conditions in the spring slow down root growth and reduce the plant's ability to take up nutrients like zinc.
- High Phosphorus Levels: An abundance of phosphorus can interfere with zinc absorption by the maize plant, sometimes referred to as P-induced zinc deficiency.
- High Organic Matter: Soils with very high organic matter, especially in the top layer, can bind with zinc, making it less available to plants.
- Soil Type: Certain soil types, particularly calcareous soils in arid and semi-arid regions, are naturally low in available zinc.
Diagnosis and Management of Zinc Deficiency
Proper diagnosis is crucial to ensure that the correct treatment is applied. Misinterpreting symptoms can lead to wasted resources and continued crop damage.
Diagnostic Techniques
- Visual Inspection: Observing the characteristic symptoms, such as interveinal chlorosis and stunting, is often the first indication.
- Soil Testing: Specialized soil tests can determine the level of plant-available zinc. The DTPA method is commonly recommended.
- Plant Tissue Analysis: A laboratory analysis of leaf tissue from symptomatic and healthy plants provides a definitive measure of zinc concentration.
Treatment and Prevention Strategies
- Soil Application: The most common approach involves applying zinc sulfate to the soil, often as a starter fertilizer band at planting. This places the nutrient close to the roots for early uptake.
- Foliar Application: For rapid correction of a developing deficiency, a foliar spray of a zinc chelate or zinc sulfate can provide an immediate boost to the plant.
- Seed Treatment: Coating seeds with a zinc-containing solution before planting can aid early root development and increase germination rates in deficient soils.
- Genotype Selection: Using maize varieties that are known to be more efficient at absorbing zinc from the soil can be a long-term solution.
Zinc Deficiency vs. Other Nutrient Deficiencies in Maize
It is important to differentiate zinc deficiency from other nutrient issues that can cause yellowing or stunting. The following table highlights key differences.
| Feature | Zinc (Zn) Deficiency | Nitrogen (N) Deficiency | Iron (Fe) Deficiency |
|---|---|---|---|
| Symptom Location | Youngest leaves first | Older leaves first | Youngest leaves first |
| Chlorosis Pattern | Broad, white-yellow interveinal bands, often near the stalk | Uniform yellowing of entire leaf, starting at the tip and moving down the midrib | Severe, distinct interveinal chlorosis on the youngest leaves |
| Growth Effect | Severe stunting and shortened internodes | Overall stunting, thin stalks | Little to no stunting initially |
| Common Cause | High pH, cold/wet soil | Insufficient fertilizer, leaching | High pH, poor drainage |
Conclusion
While what is a maize zinc deficiency called might not have a single, definitive scientific name, the term 'white bud' effectively describes its most severe form, and a range of characteristic symptoms allows for proper identification. By understanding the underlying causes, such as high soil pH and cold, wet conditions, growers can implement effective management strategies like soil or foliar zinc applications. This proactive approach helps to prevent yield loss and ensure healthy crop development. For detailed agronomic advice, consulting reputable agricultural extension services like the Purdue University Extension guide can provide further guidance.
