Turmeric can be grown in diverse tropical conditions from sea level to 1500 m above sea level, at a temperature range of 20-35oC with an annual rainfall of 1500 mm or more, under rain fed or irrigated conditions. Though it can be grown on different types of soils, it thrives best in well-drained sandy or clay loam soils with a pH range of 4.5-7.5 with good organic status.
A number of cultivars are available in the country and are known mostly by the name of locality where they are cultivated. Some of the popular cultivars are Duggirala, Tekurpeta,Sugandham, Amalapuram, Erode local, Alleppey, Moovattupuzha, and Lakadong. The improved varieties of turmeric are- Suvarna,Suguna,Sudarsana,Prabha,Prathibha,Krishna,Sugandham,Roma,Suroma,Ranga, Rasmi,Rajendra,Sonia,Alleppey, Supreme,Kedaram.
The land is prepared with the receipt of early monsoon showers.The soil is brought to a fine tilth by giving about four deep ploughing. Hydrated lime @ 500 kg/ha has to be applied for laterite soils and thoroughly ploughed. Immediately with the receipt of pre-monsoon showers, beds of 1.0 m width, 15 cm height and of convenient length are prepared with spacing of 50 cm between beds. Planting is also done by forming ridges and furrows.
Whole or split mother and finger rhizomes are used for planting and well developed healthy and disease free rhizomes are to be selected. Small pits are made with a hand hoe on the beds with a spacing of 25 cm x 30 cm. Pits are filled with well decomposed cattle manure or compost, seed rhizomes are placed over it then covered with soil. The optimum spacing in furrows and ridges is 45-60 cm between the rows and 25 cm between the plants. A seed rate of 2,500 kg of rhizomes is required for planting one hectare of turmeric.
Farmyard manure (FYM) or compost @ 30-40 t/ha is applied by broadcasting and ploughed at the time of preparation of land or as basal dressing by spreading over the beds or in to the pits at the time of planting. Zinc @ 5 kg/ha may also be applied at the time of planting and organic manures like oil cakes can also be applied @ 2 t/ha. In such case, the dosage of FYM can be reduced. Integrated application of compost (@ 2.5 t/ha) combined with FYM, biofertilizer (Azospirillum) and half recommended dose of NPK is also recommended.Fertilizers @ 60 kg N, 50 kg P2O5 and 120 kg K2O per hectare are to be applied in split doses as given below.
|Table 2. Fertilizer schedule for turmeric (per ha)|
|Basal application||-||50 kg||-||30-40 tonnes|
|After 45 days||30 kg||-||60 kg||-|
|After 90 days||30 kg||-||60 kg||-|
The crop is to be mulched immediately after planting with green leaves @ 12-15 t/ha. Mulching may be repeated @ 7.5 t/ha at 45 and 90 days after planting after weeding, application of fertilizers and earthing up.
Weeding has to be done thrice at 60, 90 and 120 days after planting depending upon weed intensity. In the case of irrigated crop, depending upon the weather and soil conditions, about 15 to 23 irrigation's are to be given in clayey soils and 40 irrigation's in sandy loams.
Turmeric can be grown as an inter crop with with chillies, colocasia, onion, brinjal and cereals like maize, ragi, etc.
Depending upon the variety, the crop becomes ready for harvest in 7-9 months after planting during January-March. Early varieties mature in 7-8 months, medium varieties in 8-9 months and late varieties after 9 months. The land is ploughed and the rhizomes are gathered by hand picking or the clumps are carefully lifted with a spade. The harvested rhizomes are cleared of mud and other extraneous matter adhering to them.
Fresh turmeric is cured for obtaining dry turmeric. The fingers are separated from mother rhizomes. Mother rhizomes are usually kept as seed material. Curing involves boiling of fresh rhizomesin water and drying in the sun.In the traditional method of curing, the cleaned rhizomes are boiled in water just enough to immerse them. Boiling is stopped when froth comes out and white fumes appear giving out a typical odour. The boiling should last for 45-60 minutes when the rhizomes turn soft. The stage at which boiling is stopped largely influences the colour and aroma of the final product. Over cooking spoils the colour of the final product while under-cooking renders the dried product brittle. In the improved scientific method of curing, the cleaned fingers (approximately 50 kg) are taken in a perforated trough of 0.9 m x 0.5 m x 0.4 m size made of GI or MS sheet with extended parallel handle. The perforated trough containing the fingers is then immersed in a pan; 100 litres of water is poured into the trough so as to immerse the turmeric fingers. The whole mass is boiled till the fingers become soft. The cooked fingers are taken out of the pan by lif ting the trough and draining the water into the pan. The water used for boiling turmeric rhizomes can be used for curing fresh samples. The processing of turmeric is to be done 2 or 3days after harvesting. If there is delay in processing, the rhizomes should be stored under shade or covered with sawdust or coir dust.
The cooked fingers are dried in the sun by spreading them in5-7 cm thick layers on bamboo mats or drying floor. A thinner layer is not desirable, as the colour of the dried product may be adversely affected. During night time, the rhizomes should be heaped or covered with material which provides aeration. It may take 10-15 days for the rhizomes to become completely dry. Artificial drying, using cross-flow hot air at a maximum temperature of 60 degree centigrade also gives a satisfactory product. In the case of sliced turmeric, artificial drying has clear advantages in giving a brighter coloured product than sun drying which tends to undergo surface bleaching. The yield of the dry product varies from 10-30% depending upon the variety and the location where the crop is grown.
Dried turmeric has a poor appearance and a rough dull outer surface with scales and root bits. The appearance is improved by smoothening and polishing the outer surface by manual or mechanical rubbing.Manual polishing consists of rubbing the dried turmeric fingers on a hard surface. The improved method is by using a 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. Turmeric is also polished in power operated drums. The yield of polished turmeric from the raw material varies from 15-25%.
The colour of the processed turmeric influences the price of the produce.For an attractive product, turmeric powder (mixed with little water) may be sprinkled during the last phase of polishing.
Rhizomes for seed purpose are generally stored by heaping in well ventilated rooms and covered with turmeric leaves. The seed rhizomes can also be stored in pits with saw dust, sand along with leaves of Strychnos nuxvomica (kanjiram). The pits are to be covered with wooden planks with one or two openings for aeration. The rhizomes are to be dipped in quinalphos 7.5ml in 10 litres of water solution for 15 minutes if scale infestations are observed and in mancozeb 35gm in 10 litres of water to avoid storage losses due to fungi.
Local Haldi China scented Thodopuza Red streaked Alleppey
'Alleppey Finger' (Kerala) 'Erode and Salem turmeric' (Tamil Nadu), 'Rajapore' and 'Sangli turmeric' (Maharashtra) 'Nizamabad Bulb' (Andhra Pradesh) In Tamilnadu, the important varieties cultivated are Erode local, BSR-1, PTS-10, Roma, Suguna, Sudarsana and Salem local. Among these varieties, 70-75% is occupied by the local varieties Allepey Finger Turmeric, Rajapuri, Madras and Erode are some of important exported varieties. Turmeric exported in the processed form is dry turmeric, fresh turmeric, turmeric powder and oleoresin. Alleppey finger turmeric is known for its high content of curcumin - a yellow colouring substance. Its bright yellow colour has been preferred by spices importers in Europe and other continents. In Middle East, the UK, USA and Japan, some of the well-accepted varieties are: 'Alleppey Finger' and 'Erode turmeric', 'Rajapore' and 'Sangli turmeric' and 'Nizamabad Bulb' India also exports turmeric in powder form and as oleoresin
Curcuma longa is the most important economically accounting for about 96% of the total area under turmeric and the remaining 4% is under C. aromatica grown in some small district of Andhra Pradesh and Tamilnadu. The varieties are categorised into three groups based on the duration of the crop
Amruthapani: Medium duration crop (8 months) highly resistant to leaf-spot but susceptible to leaf-blotch. Armoor: Long duration crop (9 months), resistant to leaf-blotch: popular variety. Duggirala: Long duration crop (9 months); tolerant to leaf-blotch; major regional variety. Tekurpeta: Long duration crop (9 months); resistant to leaf-blotch, popular variety.
Pattant: Reportedly better colour and aroma of varieties grown in region. Kerala Alleppey: High colour variety; generally marketed as Allepey turmeric. Wynad: Marketed as Alleppey turmeric.
Rajapore, Karhadi Waigon:Major regional variety.
Chinnanadan: Popular variety. Perianadan: Major regional variety; generally marketed as Madras type.