Role of Nitrogen in Onion Production

Nitrogen is a key component of enzymes, vitamins, chlorophyll and other cell constituents, all of which are essential for crop growth and development.

Nitrogen effect at growth stages

Stage Nitrogen effect
Pre-Planting Promote strong early growth
Vegetative Growth Ensure continued growth and development
Bulb Formation In nitrate forms to maintain bulb development and early growth
Bulb Fill In reduced amounts so as to maintain dry matter production but not compromise bulb quality
See more on Onion Growth Stages.

General Guidelines for Nitrogen Application

Nitrogen is the most important nutrient required for high yields and bigger bulb size. High application rates of 134lb/ac or above are usually required. Placement is more effective than broadcasting. Because the crop is shallow rooted with poor root branching, it is common practice to use split N-applications to maximize uptake efficiency. It is also important to apply nitrogen in the right form to maximise uptake during specific periods of crop growth.

Nitrogen Deficiencies in Onion

Deficient crops are slow growing and have pale yellow-green colored leaves. New leaves are thin, erect and smaller in diameter. They are also more prone to breakage.