DAUCUS (CAROTA CARROTS) & ONIONS (ALLIUM CEPA) – BETTER EXPLANATION
Daucus Carota carrots is a root vegetable grown in the cool areas of Kenya. It is commonly eaten raw in salads but can also be cooked.
Table of Contents
Ecological Requirements
Altitude: 0-2,9oom above sea level.
Rainfall:
- 750 -1,000mm.
- Well distributed throughout the growing period.
Soils:
- It requires deep,
- Fine tilth
- Well drained soils that are free from obstacles to allow for root expansion.
Temperatures:
It requires cool to warm temperatures as very high temperatures result in the production of pale and short roots.
Varieties
- Fresh market varieties for example Chantenay and Nantes.
- Canning varieties for example Nantes
- Fodder varieties for example Oxhast.
Land Preparation
- The field should be well dug to a depth of about 20cm.
- The soil clods should be broken to give a fine tilth before planting.
- Manure should not be applied as it induces forking which reduces the crop quality.
Planting
- Carrots are planted directly into the main seedbed.
- Seeds are drilled into rows made 20-30cm apart.
- The seeds are then covered lightly and the soil pressed down.
- 90kg/ha of DSP should be applied at planting time in the drills.
- It should be mixed well with the soils before placing the seeds.
Field Practice
- Thinning – it is done 2 weeks after germination.
- Weed control- the field should be kept weed free.
- Earthing up should be done while weeding to encourage root expansion ..
- Topdressing: after weeding 60kg of nitrogen per hectare should be applied as top dress.
- Irrigation – this should be carried out where or when there is not enough rainfall.
Pest Control
- Carrots do not have many field pests except the green aphids.
- These can be controlled by use of the appropriate pesticides.
Disease Control
- Occasionally attached by the mildews especially in wet and humid
- Thinning can be done to reduce humid conditions.
Harvesting and Marketing
- Carrots are ready for harvesting 3-5 months after planting depending on the variety.
- They are lifted from the soil and sold fresh or canned.
Onions (Allium cepa)
- Onions are bulb vegetables grown in the warm areas of Kenya.
- They are used as a vegetable in salads and for flavouring foods, soups and stews.
Ecological Requirements
Altitude: 0-2, 100m above sea level.
Rainfall:
- 1,ooomm of rain per year
- Irrigation in dry areas .
Soils:
- Requires well drained fertile soils
- pH of 6.0 – 7.0.
Temperatures:
- Onions are a warm climate crops.
- However, some varieties prefer cool conditions.
They require a fairly long dry period for ripening.
Varieties
- Red creole,
- Tropicana hybrid
- White creole.
Land Preparation
- The land should be well prepared leaving a fine tilth.
- Farm yard manure at 40 – 50 tonnes per hectare should be applied and mixed with the soil.
Planting
- Direct: Seeds are drilled in rows 30cm apart and 8cm within the rows. 20kg/ha of DSP fertilizer is used.
- Indirect: Seeds are established in the nurseries before transplanting them in rows 30cm apart and 8 cm within the rows.
- Shallow planting is recommended for bulb expansion.
Field Management Practices
Thinning
- It is carried out only in the crop that has been directly planted so as to achieve spacing of 8cm between two plants within the row.
- The thinned plants referred to as spring onions are used as vegetables in salads.
Topdressing
- Calcium ammonium nitrate at the rate of 25okg per hectare is recommended for topdressing onions.
- This is done 3 months after planting.
Pest Control
Onion Thrips:
- These cause silvering and withering of leaves from the tips downwards.
- They are controlled by spraying with appropriate insecticides such as Diazinon or fenthion.
Disease Control
Purple Blotch and Downey Mildew
Purple blotch;
- Characterized by oval greyish lesions with purple centres on leaves.
- This causes leaf curling and die back.
Downey mildew;
- Characterized by brown spores covering the leaves leading to death of the whole plant.
- The two diseases are effectively controlled by crop rotation and application of appropriate fungicides.
Harvesting and Marketing
- Onions are ready for harvesting 5 months after planting.
- When leaves start drying the tops are broken or bent at the neck.
- This hastens the withering of the stems.
- The bulbs are then dug out and left to dry in a shade for a few days.
- Onions are graded according to size and marketed in nets of about 14 -16kgs.
See also
CLASSIFICATION OF ANIMAL FEEDS