Onions

Yara's crop nutrition programmes for onions can help you to achieve excellent crop performance and maximise the yield and quality of all allium crops.

Planting density is a very important management factor in determining bulb size in onion crops.

A balanced crop nutrition program can help to improve overall yield by increasing onion bulb weight.

The number of onions produced is influenced mainly by plant density.

Nutrition programmes based on crop nutrient needs are key to influencing both yield and quality.

The majority of onions and garlic crops are grown for the fresh market. Bulbs should be sufficiently dry for the intended purpose.

Firmness is a critical characteristic of onion crops, particularly in dry bulb onions which are stored for long periods.

Taste and pungency are key quality characteristics of the onion crop.

A uniform skin is a major element of onion appearance for the fresh market.

Balanced crop nutrition can help to reduce storage rots by promoting healthier plants. Onions need a period of curing or drying in order to seal the neck, prevent invasion of diseases and rot and to create a bright, crack-free skin.

Onions and garlic thrive best when temperatures are cool during early development and then warmer and sunny during maturity.

Yield potentials are reached on freely drained soils where water is not limiting and nutrients are readily available.

An adequate dimension of the onion neck will prevent invasion of diseases.

Fertilizer programs starting early during establishment and vegetative growth are needed to ensure nutrients don’t limit onion bulb quality.

It is particularly important to ensure that environmental and growth constraints do not limit bulb formation and bulb quality.

The majority of onions are grown for the fresh market and are usually graded prior to marketing.

In order to maximise the fertilizer use efficiency, timing of nutrient applications must match crop demand.

Onions can survive at temperatures of - 6°C, but are killed when conditions drop below -8°C.

Modern cultivated types of onion fall into two main groups - the common onion and aggregatum group.

54 million tonns of dry onions are produced annually, with the crop being grown across 3 million hectares in over 134 different countries.

Onions are slow to emerge.

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

Phosphorus is a component of nucleic acids (DNA and RNA) and essential for energy transfer within the plant.

Potassium is involved in the production and transport of carbohydrates and sugars to the bulb, enzyme activation and synthesis of proteins.

Calcium is a key component of cells maintaining the structure of cell walls and stabilizing cell membranes.

Magnesium is required for many processes including transfer of energy and protein synthesis.

Sulfur is an important component of enzymes and other proteins, and is required for chlorophyll formation.

Boron is involved with carbohydrate metabolism and protein synthesis.

Copper has a key role to play in lignin formation.

Iron is associated with chlorophyll formation and photosynthesis.

Manganese is required for chlorophyll formation and oxide-reduction reactions in cells.

Molybdenum is an important component of nitrate reductase and thus involved in nitrogen metabolism as well as the synthesis of pigments and chlorophyll.

Zinc is important for the development and function of growth regulators (e.g. auxin) that influence internode elongation.