Nitrogen
Nitrogen is one of the most important nutrients required for high onion yields. Onions are known as gross feeders and crops can remove 2-3 kg of nitrogen for every ton harvested.
Influencing onion bulb number
The number of onions produced can be influenced by a variety of factors, for example, plant density. Planting crops at higher densities can result in greater numbers of onion bulbs, but of smaller size. Thus, it is important to manipulate sowing density to provide maximum yields of a desired bulb size. A balanced fertilisation program will help to reach yield potentials.
Crop Nutrition and Onion Number
Potassium
Potassium is important for high yields in onion crops. It is the second most utilized nutrient and uptake peaks during bulb formation and enlargement. However, care has to be taken as over-application can lead to yield reductions.
Calcium Nitrate
Studies with calcium nitrate confirm this is one of the most effective forms for high yields.
Zinc
Trials have shown that zinc nutrition can improve seed germination and seed yield, both important for high yields.
Related articles
How to increase onion yield
Onions have a relatively low nutrient uptake efficiency, due to their shallow root system characterised by thick roots with very few and short hairs. So to achieve optimum yields it is important to apply nutrients as close as possible to the rooting zone...
Improving onion bulb firmness
Firmness is a critical characteristic of onion crops, particularly in dry bulb onions which are stored for long periods. Growers can influence bulb firmness by applying balanced nutrition.
Maximising onion bulb dry matter content
The majority of onion crops are grown for the fresh market. Bulbs should be sufficiently dry for the intended purpose. Most common bulb onions have 10-12% dry matter. Onions grown for dehydration require higher dry matters of 17-20%. Nitrogen and...
Improving onion quality
It is particularly important to ensure that environmental and growth constraints do not limit onion bulb yield, and thereby quality. Taste and pungency are important elements in determining the quality of onion crops.
