A guide to Nutrient Deficiencies – Manganese

Manganese (Mn) is an essential micronutrient for plants, and manganese deficiency in horticulture can lead to various symptoms and impacts on plant health and growth.

What are the symptoms of Manganese Deficiency?

• Interveinal Chlorosis: One of the most common and noticeable symptoms of manganese deficiency is interveinal chlorosis, where the area between the veins of the leaves turns yellow while the veins themselves remain green. This gives the leaves a net-like appearance.
• Necrosis: In severe cases, the chlorotic areas may become necrotic, leading to the death of tissue between the veins, which can result in reduced leaf size and overall plant vigor.
• Leaf Discoloration: Manganese-deficient plants may also display other symptoms like reddish or purplish discoloration in the older leaves, especially along the leaf margins.
• Reduced Growth: Manganese deficiency can significantly reduce plant growth, including stunted growth, reduced flower and fruit production, and poor root development.

Manganese Deficiency in Kalmia

What are the impacts of Manganese Deficiency?

• Reduced Photosynthesis: Manganese is essential for the functioning of photosystem II in chloroplasts, so its deficiency can impair photosynthesis, leading to reduced energy production for the plant.
• Nutrient Uptake: Manganese deficiency can disrupt the uptake of other nutrients like iron and calcium, further exacerbating nutrient imbalances in the plant.
• Increased Susceptibility to Diseases: Weakened plants are more susceptible to diseases and pests, so manganese deficiency can make horticultural crops more vulnerable to various pathogens.

Manganese Deficiency in Spathiphyllum

How should you manage Manganese Deficiency?

• Soil Testing: Conduct soil tests to determine the manganese levels in the soil. If the soil is deficient in manganese, corrective measures can be implemented.
• Fertilisation: Manganese sulfate or chelated manganese can be applied as a foliar spray or incorporated into the soil as part of a balanced fertiliser program. The application rate should be based on soil test recommendations and the specific crop requirements.
• pH Adjustment: Manganese availability is influenced by soil pH. If the soil pH is too high (alkaline), manganese may become less available to plants. Adjusting the soil pH to the appropriate range for the specific crop can help improve manganese uptake.
• Avoid Over-Irrigation: Excessive irrigation can lead to leaching of manganese from the soil, making it less available to plants. Proper irrigation management can help conserve manganese in the root zone.
• Crop Rotation: Rotate crops to reduce the risk of manganese deficiency since different plants have varying nutrient requirements and susceptibilities to deficiencies.
• Organic Matter: Incorporating organic matter into the soil can improve manganese availability over time.

Manganese Deficiency in Pieris

It’s important to note that excessive manganese levels in the soil can also be detrimental to plants, so it’s essential to monitor manganese levels and apply corrective measures judiciously based on soil tests and crop needs. Regular observation and early intervention are key to preventing and managing manganese deficiency in horticultural crops.