CROP HUSBANDRY-TURMERIC CULTIVATION PRACTICES IN KERALA

TURMERIC (Curcuma longa)


Turmeric is a tropical herb and can be grown on different types of soil under irrigated and rainfed conditions. Rich loamy soils having good drainage are ideal for the crop. It is a shade tolerant crop with shallow roots suitable for intercropping and also as a component crop in the homesteads where low to medium shade is available.

Preparation of land
Prepare the land to a fine tilth during February-March. On receipt of pre-monsoon showers in April, prepare beds of size 3 x 1.2 m with a spacing of 40 cm between beds.

Seed material
Whole or split mother rhizomes are used for planting. Select well developed, healthy and disease free rhizomes. Treat the rhizomes in any of the copper oxychloride fungicides and store in cool, dry place or in earthen pits plastered with mud and cowdung.

Varieties
The important varieties are Duggirala, Tekurpetta, Sugantham, Kodur, Armoor, Alleppey, Suvarna, Suguna, Sudarshana, Prabha, Prathibha, Kanthi, Sobha, Sona and Varna.

Season and method of planting
Plant during April with the receipt of pre-monsoon showers. Take small pits in the beds in rows with a spacing of 25 x 25 cm. Plant finger rhizomes flat with buds facing upwards and cover with soil or dry powdered cattle manure. The seed rate is about 2000-2500 kg per ha.

Manuring
Apply cattle manure or compost as basal dose at 40 t/ha at the time of land preparation or by spreading over the beds after planting. Apply N:P2O5:K2O @ 30:30:60 kg/ha. Full dose of P2O5 and half dose of K2O may be applied as basal; 2/3 dose of N may be applied at 30 days after planting; and 1/3 N and remaining K2O may be applied 60 days after planting.

Mulching
Mulch the crop immediately after planting with green leaves @ 15 t/ha. Repeat mulching after 50 days with the same quantity of green leaves.

Aftercultivation
Weed the crop thrice at 60, 120 and 150 days after planting, depending upon weed intensity. Earth up the crop after 60 days.

Intercropping
Chilly, maize and colocasia can be grown as intercrops.

Harvesting and curing
Time of harvest depends upon variety and usually extends from January to March. Harvest early varieties at 7-8 months, medium varieties at 8-9 months and long duration varieties at 9-10 months after planting.

Improved method of processing

Cleaning: Harvested turmeric rhizomes are cleaned off mud and other extraneous materials adhering to them and subjected to curing within 2-3 days after harvest so as to ensure the quality of the end product.

Boiling: Fingers and mother rhizomes will have to be boiled separately. Boiling is usually done in MS pans of suitable size. Cleaned rhizomes (approximately 50 kg) are taken in a perforated trough of size 0.9 m x 0.55 m x 0.4 m made of GI or MS sheet with extended handle. The trough containing the rhizomes is then immersed in MS pan (1 m x 0.62 m x 0.48 m) containing clean water sufficient to immerse the rhizomes. The whole mass is boiled till the rhizomes become soft. The correct stage of cooking can be judged by piercing a wooden needle through the rhizome. If the rhizomes are properly cooked, the needle will pass through the rhizome without resistance. The cooked rhizomes are taken out of the pan by lifting the trough and draining the solution into the pan.

Drying: The fingers are then dried in the sun by spreading them as a thin layer on bamboo mats or drying floor. Artificial drying at a maximum temperature of 65ºC gives a bright coloured product than that of sun drying especially for sliced turmeric.

Polishing

In order to smoothen the rough and hard outer surface of the boiled dried turmeric and also to improve its colour, it is subjected to polishing. There are two types of polishing, hand polishing and machine polishing.

Hand polishing: The method of hand polishing is simple, which consists of rubbing turmeric fingers on hard surface or trampling them under feet wrapped in gunny bags. The improved method is by using hand-operated barrel or drum mounted on a central axis, the sides of which are made of expanded metal mesh. When the drum filled with turmeric is rotated, polishing is effected by abrasion of the surface against the mesh as well as by mutual rubbing against each other as they roll inside the drum.


Machine polishing: This method consists of an octagonal or hexagonal wooden drum mounted on a central axis and rotated by power.

Colouring
Boiled, dried and half polished turmeric fingers (half polished turmeric is more suitable since colour does not stick to the rhizomes that have been polished fully to smooth finish) are taken in bamboo basket and shaken with turmeric powder. For coating 100 kg of half polished turmeric 200 g of turmeric powder is required. When fingers are uniformly coated with turmeric powder, they are dried in the sun.

Turmeric oleoresin
This is obtained by the solvent extraction of the ground spice with organic solvents like acetone, ethylene dichloride and ethanol for 4-5 hours. It is orange red in colour. Oleoresin yield ranges from 7.9 to 10.4 per cent. One kg of oleoresin replaces 8 kg of ground spice.

Plant protection
No major incidence of pest or disease is noticed in the crop. Shoot borers can be controlled by spraying 0.05% dimethoate or 0.025% quinalphos.

Leaf spot and leaf blotch can be controlled by spraying 1% Bordeaux mixture or 0.2% mancozeb. If symptoms of early wilt or rhizome rot appear, drench the soil with cheshunt compound or 1% Bordeaux mixture.