It is also involved in the metabolism and synthesis of proteins.
|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.
As all other micronutrients, manganese plays a role in seedling and leaf growth. Without good leaf productivity, growth slows and yield suffers.
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.