- Mo is mobile in plant and is relatively mobile in soil. Hence, its deficiency is noticed on older leaves.
- Root nodule bacteria in legumes are dependent on Molybdenum, whose inadequate supply leads to poor nodule formation, less bacterial activity and light green colour of leaves, typical of Nitrogen starvation.
- Mixing of Ammonium or Sodium Molybdate with Phosphatic fertilizers proved very effective to increase Molybdenum use efficiency.
- Component of Nitrogenase (an enzyme associated with Nitrogen fixation by rhizobium-legume symbiosis) and Nitrate Reductase (an enzyme associated with Nitrate Metabolism in plants) enzymes.
- It acts as an activator for both the enzymes, thus not only helps in Nitrogen fixation but also in its assimilation in the plant.
- It is important in building Amino Acids and Proteins and helps in Sulphur metabolism.
GENERAL DEFICIENCY SYMPTOMS
- Older leaves exhibit chlorosis with interveinal necrotic spots, scorching of leaf margins.
- Curling, rolling and cupping of leaves and gummy exudates on lower leaf surfaces.
- Older leaves become abnormally large sized whereas the younger ones remain very small.
- Poor nodulation in leguminous crops.
- Growing points die, flower drop.
SPECIFIC DEFICIENCY SYMPTOMS
- Leaf spots in Citrus.
- Leaf disorders in Chilli, Okra, Brinjal, Tomato, Cotton, etc.
- Whip tail in Cauliflower
CAUSES OF MOLYBDENUM DEFICIENCY
- Highly acidic / alkaline soils and coarse textured / sandy soils.
- The soils low in organic matter.
- The soils subjected to long periods of moisture stress.
Legumes, Citrus, Maize, Cotton, Cauliflower, Clover, Lettuce, Spinach, Some vegetables, Chilli, Grapes