Carrots Farming


Carrot is a biennial crop. The leaves are feather like with long petioles and they are severally divided into sections. The sheath of the petiole opens at the base. The flowers are white, small and borne in compound terminal umbels. Carrot is propagated by seeds. The thickened fleshy root is the edible portion. The shape, color and size of the root vary according to varieties.

Importance:

Carrot gained importance in the human diet because of its nutritive value. The edible root is an excellent source of Vitamin A. It also contains appreciable amounts of food energy and many other food nutrients necessary for the body.

Varieties:

New Kuroda - Root is dark red, tapered with the length of 16 to 20 cm. Strong vigorous plant. Tolerant to Alternaria. Maturity days 80 to 100 days.

F1 Japan Cross - Kuroda hybrid type resistant to heat. Maturity from sowing, 110 to 120 on cool season, 90 to 95 days in hot season. Vigorous plant. roots are along slightly tapered, with uniform dark red color, 18 to 20 cm long. Resistant to Alternaria. High yield 30 to 35 tons per ha.

Other varieties include:

Nantes Improved, Touchon, Chantenay, Colmar, F1 Amazonia.

Adaptation:

Climatic and Soil Requirements - Carrot is known to be a temperate and semi temperate crop. In the Philippines, it can grown successfully at high levations with a cool environment. It can also be grown in lowland areas but the growing period should be during the cool months of the year if good stand and yield are desired. The crop is usually planted from October to December.

The optimum pH for carrot is about 5.5 to 7.0. It has little tolerance to high salt content, but is moderately tolerant to high boron in the soil. It requires a very deep, well drained soil preferably sandy loam. However, careful control of soil moisture by furrow irrigation permits use of heavier soil than is recommended.

Carrot can also be planted in loam and slit loam soils but it is usually difficult to establish good stands in these soil, unless crust formation can be avoided. Clay soils impair root shape, and harvesting from clay soils is difficult. Coarse, undecomposed, organic matter in the surface soil tends to impair root shape.

Nutrients - Little is known in the Philippines as to the nutritional requirements of carrot, except that when applied with the correct amount of complete fertilizer, it responds satisfactorily.

Requirements:

Field Preparation - The land should be plowed and harrowed several times until a fine filth is attained. Thorough field preparation is very necessary for the plant because it is small- seeded and usually planted direct in the field. Besides, field preparation seems to have something to do with the development of the roots. Crops planted in a well-prepared field seem to have better well-shaped, marketable roots than plants grown in a poorly prepared soil which tend to have irregularly-shaped
roots.

Planting and spacing - Carrot is usually directly seeded. In a small plantation or backyard garden, it is either broadcast or planted in furrows spaced 20 cm. between rows and about 5 cm. In the row, on a slightly elevated plot. In big commercial plantation, seeds are drilled evenly or planted in hills in shallow furrows, about 1 to 2 cm. deep, covered with a thin layer of fine soil. The spacing is about 20 to 30 cm between rows and about 5 cm. in the row.

The seed requirement per hectare will depend much on the percentage of germination and spacing. The lower the percentage of germination and the closer the planting, the more seeds are required per hectare. Under normal conditions, that is, if the germination is from 80 to 90 percent, a hectare usually requires 4 to 6 kg. of seeds.

Cultivation and thinning - Carrot is a slow starter plant both in terms of germination and growth at the seedling stage. It germinates after ,six to 21 days from sowing at a temperature of about 20 to 24 degree centigrade. At seedling stage, the plants are slender and incapable of competing with the weeds. It is therefore, advisable to keep weeds completely down at the early stages of growth of the plants to have a good uniform stand. Shallow cultivation is started as soon as the first true leaves appear.

Thinning is done only when the plants are about 15 cm. in height. At this stage, the plants are already more or less established. It is also recommended that during the last cultivation, this soils be thrown toward the base of the plants to avoid the development of green pigments on the shoulder of the roots which may effect their market value.

Irrigation - Carrots need a constant supply of moisture throughout the growing season to produce uniform and tender quality roots. In areas with adequate rainfall or with enough soil moisture during the growing season, irrigation can be dispensed with. In places with less rainfall or soil moisture, irrigation is profitable. Frequent, light irrigation is preferable to heavy irrigation. Never allow water to stay too long in the field as this would encourage root disease and rotting.

Crop rotation - Planting of crops alternately in a piece of land is a good agricultural practice not only in the control of pests and diseases but also in maintaining the soil productivity. The rotation should be planned according to the purpose of the grower. If the rotation is designed for the control of pest and diseases, the crop to be rotated should not be an alternate host of the pest of disease-causing agent; if for the maintenance of soil fertility, planting of leguminous crops after carrot is suggested. In soil heavily infested with root-knot nematodes, it is advisable to rotate with corn, sorghum and some resistant varieties of cowpea, peanut or beans.

Fertilizer application - In the absence of soil analysis, it is advisable to use 500 to 600 kg. of the complete fertilizer (14-14-14) or (12-12-12) per hectare. It must be broadcast during the last harrowing and properly incorporated with the soil before planting.

Control of Pests and Diseases

Pests and their Control:

1. Cutworm, Prodenia litura Fabricius. The larva is a brown worm about 5 cm long. The adults are blackish gray both have pale marks across the wings, about 2 cm long. The eggs are laid on the lower surface of leaves in a mass several hundreds and covered with mooted hair. The worm feeds at night and hides in the soil during the day. The larva feeds on leaves and stems of young plants.

Control - Spray with Sevin, Methylparathion or Parathion.

2. Aphids, Aphis sp. Small, greenish insects, winged or wingless. They reproduce rapidly. They feed on the leaves of the plant.

Control - Spray with Sevin, Malathion and other systemic insecticides
found in the market.

3. Root nematode or gall-worm or eel worm, causes root knot and is scientifically known as Meloidogyne sp. It is worm ordinarily too small to be seen by the naked eye. It is disseminated by means of infected soil, water and diseased root crops.

In root-knot, the tissue is stimulated to abnormal growth so that the invaded roots become two to three times larger in diameter than normal and finally they decay. The top of the plant, being robbed of the food which goes to the swollen roots and at the same time deprived of water absorbing area, is stunted, pale and inclined to wilt. The affected plants may linger through the growing season, although most of them die prematurely.

Control - Long rotation with crops highly resistant to the lest like corn, sorghum and some resistant varieties of cowpea, peanut and beans is recommended.

Diseases and their Control:

1. Bacterial blight (caused by Xanthomonas carotae) the first symptoms are yellow spots on the tips of leaf segments. They rapidly turn brown and get a water soaked appearance. A yellowish circle often subtends the black center of the lesion. Entire leaf segments or leaflets are killed. Lower leaves die and dry up as the disease advances. In severe infections, long dark-brown, water soaked lesions develop on the petioles and main stem. A gummy, bacterial substance frequently collects on them.

The affected roots may show small, water soaked greasy flecks or scab-like lesions at any point on the surface. They first appear as brown or maroon spots, which may become raised pustules or sunken craters.

The large craters usually crack open and are drilled with soil particles embedded in the bacterial oose. Often, internal lesions heal over to enclose the scab lesion.

Control - The bacteria persist in the soil and are commonly carried by the seed. Seed may be disinfected by soaking in hot water at 120 degree F for 10 minutes. Control also requires adequate crop rotation.

2. Bacterial soft rot ( caused by Erwinia carotovora). It is one of the most destructive diseases of carrot and other vegetables in storage and transit. The disease is recognized by a watery, smelly, soft decay on storage tissue. It normally invades plants through wounds.

Control - Avoid bruising the roots during harvest. Cool, dry storage will help in the control of the disease.

3. Cercospora blight (caused by Cercospora carotae). The disease is more severe in young leaves than in old leaves. Lesions are usually marginal although any part of the leaf or petiole may be attacked. It is characterized by gray to brown, circular or elongated, localized spots that are usually whitish or tan at the center.

Control - Crop rotation. Spray weekly with Maneb and Zineb until the crop is mature.

Harvesting, Curing and Storing:

Harvesting and Handling - Crops planted for early market are harvested as soon as the roots reach the acceptable size. This is about three to six months after sowing, depending upon the variety. Yellowing of leaves may indicate maturity but it is not a sure index. The surest and most practical way to determine the size of the roots is to scratch the base of the plants and to see the actual size of the roots by pulling some samples in the population.

Carrots are pulled when they have the desires root size. The roots are highly variable in size and maturity. If harvested at one time, considerable loss in total yield may result. Therefore, it is possible, carrot should be harvested one after the other as they mature.

Sorting should be done as they are harvested or gatherer from the field. Split and branched roots should be discarded. If the crop will be marketed in bunch, only dried leaves should be removed. Bunching maybe one right in the field or in the shed. Leaves should be cut to the minimum to avoid rapid with ring or shrinking of the roots. The tops are removed by cutting or twisting by hand right after the crop is pulled or harvested.

Top of carrot draw moisture from the roots and hasten shriveling removing the tops doubles the shelf life of the roots. Removing tops and packing them in one pound, moisture-proof film bags further reduce moisture loss and increase shelf life.

Bunched carrots when displayed six days at 70 degree F with 50 percent relative humidity lose 48 percent in weight; with tops removed, 29 percent; and in a perforated polyethylene bag, 4 per cent. Under refrigeration, polyethylene packaged carrots have a shelf life of at least two to three weeks and moisture loss is usually less than one per cent.

Reference: Cultural Directions for Phil. Agricultural Crops. Photo courtesy of http://library.thinkquest.org

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