How to Control Manganese Deficiency in Wheat?

Symptoms of Manganese Deficiency

• Interveinal Chlorosis: The most common symptom is yellowing between the veins of the leaves, while the veins themselves remain green. This gives a striped or streaked appearance.
• Greyish-Brown Spots: In severe cases, small greyish-brown spots or streaks may develop on the yellowed areas, particularly on the middle leaves. These spots can merge to form larger necrotic (dead) patches.
• Stunted Growth: Overall plant growth is stunted, and tillering may be reduced.
• Reduced Yield: Severely affected plants produce fewer and smaller grains, leading to significant yield losses.

Causes of Manganese Deficiency

• High Soil pH: Manganese availability decreases significantly as soil pH rises above 6.5. Alkaline soils are particularly prone to this deficiency.
• Sandy Soils: These soils often have lower manganese reserves and can leach manganese easily.
• High Organic Matter: While organic matter is generally good, in some cases, it can bind manganese, making it unavailable to plants, especially in poorly drained conditions.
• Poor Drainage: Waterlogged conditions can reduce manganese availability.
• Cold, Wet Weather: These conditions can reduce root activity and nutrient uptake, exacerbating deficiency.
• High Iron Levels: Excessive iron in the soil can sometimes interfere with manganese uptake.

Correction Methods

Foliar Application (Most Effective): Foliar sprays are highly effective because manganese is directly absorbed by the leaves, bypassing soil fixation issues.

• Timing: Apply when symptoms first appear, typically 30-45 days after sowing (DAS) during the tillering stage. A second spray might be needed 10-15 days later if symptoms persist.
• Dosage: Use Manganese Sulphate (MnSO4).

Soil Application (Less Efficient): While possible, soil application is often less effective due to manganese fixation, especially in alkaline soils.

• Timing: Apply before sowing or at the time of sowing.
• Dosage: If soil application is chosen, it should be significantly higher than foliar application.

Always ensure thorough coverage of leaves during foliar sprays. Use a sticker/spreader for better absorption.

Preventive Measures

• Soil Testing: Regular soil testing helps identify potential manganese deficiencies before planting. This allows for corrective measures.
• Maintain Soil pH: Where possible, manage soil pH to be slightly acidic to neutral (6.0-7.0) for optimal manganese availability. However, altering pH significantly can be challenging.
• Organic Matter Management: Incorporate well-decomposed organic matter. While high organic matter can sometimes bind Mn, balanced organic matter improves soil health and nutrient cycling.
• Crop Rotation: Rotate wheat with crops that have different nutrient requirements or are less sensitive to manganese deficiency.
• Resistant Varieties: Choose wheat varieties known to be more tolerant to manganese deficiency, if available for your region.

Controlling manganese deficiency in wheat is crucial for maintaining yield. Early detection of symptoms like interveinal chlorosis and prompt foliar application of manganese sulphate are the most effective strategies. Regular soil testing and good soil management practices can help prevent this deficiency.