Introduction
Turmeric is an important spice crop. This spice is the dried, modified stem called Rhizome. In Goa the traditional local varieties of Turmeric was grown in small areas as rain fed crop for domestic use of turmeric as spice and medicine. The leaves are used for flavouring other steamed local delicacies like Patolyo’, `Sanna’ etc.
Recently with introduction of high yielding varieties like ‘Prabha’ and ‘Pratiblia’ ‘Sudarshan’ few horticulturists in Goa are growing turmeric on commercial bases. There are huge demands for turmeric grown organically.
Turmeric is a tropical crop, thus Goa’s climate is suitable for growing it. However very heavy showers during July -August suppress the growth of this crop.
Turmeric comes well from sea level to 1500mts above MSL so it can be cultivated in any part of Goa.
Climate and soil
Turmeric prefers a warm, humid climate with a rainfall of 1,500mm and temperature of 20°-30° C. It thrives well up to 1,200m above sea level. Well drained sandy or clayey loam or red loamy soils having acidic to slightly alkaline ph. are ideal for its cultivation.
Propagation:
Whole or split mother rhizome or finger rhizomes are used for planting. Seed @ 2,500kg/ha is optimum. Each planting unit consists of bits of 20-25g each. The seed rhizomes are treated with Dithiane M-45(0.3%) and exalux(0.2%) for 30 minutes before storage as well as during the planting time.
It is either planted on raised beds of 1m width and convenient length with 15cm height or on ridges and furrows or in flat system. The spacing is kept 30cmx15cm or 30cmx20cm(in beds), 40-60cmx25cm(on ridges and in furrows) and 50cmx15cm (in flat system)
Manuring and fertilization
A basal dose of farmyard manure@ 40 tones/ha may be incorporated at the time of land preparation. A fertilizer dose of 60:50:120kg NPK/ha is recommended. The entire dose of K20 and half of P205 is applied as adbasal dose. Half of N is given 45 days after planting and other half with the remaining dose of P205 is given 3 months after planting.
The general dose of fertilizer should be 30-120 Kg N, 30-60Kg P,and 60-120kg K/ha depending on place and growing conditions(irrigated/non-irrigated0in 3 splits. The beds should be earthed up after each fertilizer application.
The crop is mulched immediately after planting with green leaves@1,200-15,000kg/ha. It may be repeated for a second time with the same quantity of green leaves after the second fertilizer application.
Aftercare:
First earthing up should be given 50-60 days after planting and the next after 40 days. It cannot withstand prolonged waterlogging and also does not tolerate heavy shade.
Intercropping
Turmeric comes up well under sparse shade also. It can be grown as an intercrop in coconut gardens like ginger or as mixed crop with red gram, chilli, colocasia, vegetables, maize and ragi.
Irrigation:
Turmeric can be grown either as a rainfed crop (Kerala, Orissa and north eastern states) or an irrigated crop (Andhra Pradesh and Tamilnadu)depending on location. In case of irrigated crop, depending on weather and soil conditions, 15-40 irrigations may be necessary at 7-10 days intervals.
Turmeric comes up well under partial shade conditions but thick shade affects the yield adversely. There is no severe pest or disease incidence on turmeric crop. However following pest and diseases affect the crop.
Shoot Borer: This insect pest tunnels into shoot and feeds on the growing point. The central Shoot dies and comes out easily when pulled. Pest incidence can be deleted by the presence of holes on the shoot yellowish withered central shoot.
This insect can be managed by spraying dimethoate 30% EC@ 20 ml in 10 L of water.
Rhizome Rot : This is major soil borne disease of turmeric and spreads from infected Rhizome turns soft and extensive tissue rotting occurs. However this disease can be diagnosed first through leaf symptoms. Leaves of affected plants starts yellowing along the margins and finally leaves droop down.
This disease can be managed by selecting disease free rhizomes for planting. Affected area in early stage can be drenched with 1% Bordeaux mixture. Antagonistic fungus Trichoderma viridine can also be added to the soil along with manure
Harvesting and post harvest technology
Turmeric takes 7-9 months for harvesting. Drying up of the aerial portion indicates maturity. On an average, a yield of 25-30 tones/ha of fresh rhizomes may be obtained.
The harvested rhizomes are washed well to remove adhering soil. The fingers are separated and cooked in boiling water for 1hr under slight alkaline condition(100g of sodium bicarbonate or sodium carbonate in 100 L of water)and sun dried on bamboo mat or drying floor for 10-15 days. For boiling turmeric usually copper galvanized/iron or earthen vessels are used. It takes 40-60 minute of boiling to reach the correct stage.
The dry recovery varies from 15-30% depending on variety, location and cultural practices. The dried turmeric is subjected to polishing either manually by rubbing it on concrete flooring or mechanically in power operated drums. Turmeric powder is added to the drum either as powder or as emulsion for giving bright colour to the rhizome.