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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.
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.
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.
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.
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.
Intercropping
Chilly, maize and colocasia can be grown as intercrops.
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.
Aftercultivation
Weed the crop thrice at 60, 120 and 150 days after planting,
depending upon weed intensity. Earth up the crop after
60 days.
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.
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.
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