Role of Manganese in Onion Production

Manganese is required for chlorophyll formation and oxide-reduction reactions in cells. It is also involved in the metabolism and synthesis of proteins.

Manganese effect at growth stages

Stage Manganese effect
Pre-Planting Ensure good shoot growth
Vegetative Growth Ensure photosynthetic growth is not limiting
Bulb Formation To maintain leaf growth
Bulb Fill  Less critical, but to maintain growth and prolong bulking
See more on Onion Growth Stages.

General guidelines for Manganese application

As all other micronutrients, manganese plays a role in seedling and leaf growth. Without good leaf productivity, growth slows and yield suffers.

Manganese deficiencies in onion

Onions are very susceptible to manganese deficiency. The outer leaves show striped interveinal chlorosis. This develops into tip-burn and curling leading to necrosis. Growth slows, plants become stunted and bulb formation is delayed. At maturity, bulbs have a thick neck. Deficiencies are worse on sandy soils and those with a high pH. Intermittent deficiencies are found in poorly consolidated seedbeds or where soils are particularly dry.