Manganese Deficiency in Coconut

Manganese deficiency in coconut
Manganese (Mn) is a trace element required in a minimal quantity, but it is an essential micronutrient for coconut palms. Manganese is required for certain plant metabolic activities, such as photosynthesis and enzyme activation, that help produce sugars, proteins, and other vital compounds.

Symptoms of Manganese Deficiency in Coconut

• The most common symptom of manganese deficiency is interveinal chlorosis, i.e., leaves turning yellow between the veins but remaining green in the veins.
• The Manganese deficiency symptoms appear as chlorosis  (yellowing)  of the innermost younger leaves along with longitudinal necrotic streaks.
• Since manganese plays a key role in chlorophyll production, its deficiency can result in a pale, yellowish appearance of the leaves.
• The younger leaves are deformed due to curling and the overall aesthetic appearance of the palm will be affected.
• In severe cases, the yellowing can progress to death of tissue (necrosis), with brown spots or speckling, particularly at the tips and edges of the affected leaves.
• Except for the basal portions of the leaflets, all newly emerging leaflets show necrotic symptom
• resulting in curling of the leaflets giving the leaf a ‘frizzle top’ appearance.
• Consequently, necrotic leaflet tips fall off and the leaf has a signed appearance.
• In severe cases, necrotic petiole stubs only remain on newly emerging leaves.
• Deficiency can lead to inferior coconut and poor yield.

Causes of Manganese Deficiency: 

• Soil pH Imbalance
  Manganese availability is highly dependent on the soil pH. If the soil is too alkaline (high pH), manganese becomes less available for uptake by the roots. Soils with a pH above 6.5 are often prone to manganese deficiencies.
• Low Soil Manganese Content
  Some soils, particularly sandy or poorly developed soils, naturally have low levels of manganese, which can lead to deficiency if not managed properly.
• High Phosphorus Levels
  Excessive phosphorus in the soil can interfere with manganese uptake. High phosphorus levels can "tie up" manganese, making it unavailable to plants.
• Waterlogging
  Poor drainage or waterlogged soils can lead to reduced oxygen levels around the roots, which affects the plant’s ability to absorb manganese and other nutrients.
• Soil Compaction
  Compacted soils can restrict root growth and reduce the plant's ability to access manganese and other essential nutrients.

How to rectify Manganese Deficiency?

1. Conduct periodical soil tests, especially in alkaline soil, to check soil pH and status of manganese in the coconut garden. Based on the available nutrient status, recommended fertilizer may be applied as per the recommended dose.
2. The following fertilizers may be applied for compensating the shortage of Manganese.

• Manganese Sulfate(MnSO₄ ) can be applied as a foliar spray or soil amendment.
• Chelated Manganese is another option that is more easily available to palms, especially in alkaline soil.
• Manganese sulfate can be applied directly to the leaves as a foliar spray, which is quickly absorbed by the palms.

3. The addition of elemental sulfur or organic matter like compost can help lower soil pH.
4. As water-logged conditions, hamper the nutrient uptake, proper drainage is to be provided to avoid water logging.
5. Avoid applying phosphorus in excess, which can interfere with manganese uptake. Follow balanced fertilizer application.
6. Manganese and other micronutrients may be applied in the right proportions.
7. Adding organic matter, such as compost, can improve soil structure, enhance microbial activity, and make micronutrients like manganese more available to plants.
    

The deficiency of Manganese shall be managed very well through proper soil management, fertilization, and pH control and we can ensure the overall productivity of coconut palms.