|
For more information
click
here to email us
(only business inquieries
will be answered)
|
|
 The
onion crop cycle (Allium cepa L.)
|
|
The onion cycle has 10 development stages, from
planting to bulb maturity. Learning to recognize each stage is essential
to implement an efficient crop management program.
|
|
|
|
|
Seed
Seed in soil after planting.
|
|
Germination
After the underground germination, the cotyledon appears. It looks
like an arch.
|
| |
|
|
|
|
|
|
First leaf
When the first leaf emerges [1], the plant is still in the flag
stage.
|
Cotyledon fall
After a progessive drying out and the emergence of leaves 2 and
3, the cotyledon falls. This stage is very important for an integrated
weed control program.
|
Fall of first leaf
After the first leaf dries out and falls, the second leaf falls
while the 5th, 6th and 7th leaves appear.
|
| |
|
|
|
|
Bulb forming
The bulb starts to form; the 2nd and 3rd leaves dry out while
leaves 8 to 13 appear; the plant is at its maximum development.
|
Bulb thickening
Beginning of the regression of the vegetative phase. Drying out
of leaves 4, 5 and 6 and of the end of the main leaves: due to
their weight, some leaves fold; new smaller leaves may appear;
the bulb becomes visible; the tunic starts to form. Note the shallow
root system at this stage. Care must be taken not to prune these
roots wih cultivation.
|
|
|
 |
Laying down plant
The vegetative phase is over; The leaves lay down on the soil
and start to dry out. The bulb has almost reached its final size.
|
Bulb maturity
The tunic is finished. The leaves and the neck are completely
dry. When harvested, the bulb, completely closed, is seperated
from the aerial part.
|
|
|
Source: Drawings based on data from
Ch. Rey, J. Stahl, Ph. Antonin, G. Neury. In L'oignon de garde,
CTIFL ed, Paris, France.
The crop is characterized by a slow germination
and growth speed as well as a shallow root system which musn't be injured.
The cycle length depends on the variety
and ranges from 120 to 180 days.
Soil types
Onions will grow in a wide range of soil types. We recommend however the
choice of friable soils; their high water retention potential will preserve
the shallow root system. Avoid heavy clay soils which can block root growth
and lead to problems at harvest.
Ecophysiology - bulb
A minimum day-length is necessary for bulb formation. The threshold value
depends on varieties: around 12 to 13
hours for tropical areas. Bulb thickening is related to outdoor temperature:
temperatures above 18°C start bulb thickening.
Nutrient requirements
For nitrogen, the crop requirement not only depends on yields but also
on the product destination (i.e market demand).
|
| ICS | 
|
|
| 
SEEDS & agricultural MACHINERY - with expertise and services for successful crop management
