Turmeric (Curcuma longa) (Family: Zingiberaceae) is used as condiment, dye, drug and cosmetic in addition to its use in religious ceremonies. The tuberous rhizomes or underground stems of turmeric are used from antiquity as condiments, a dye and as an aromatic stimulant in several medicines. Presently it is cultivated in China, Taiwan, Indonesia, Sri Lanka, Australia Africa, Peru and West Indies.
India is a leading producer and exporter of turmeric in the world. In India, Turmeric is mainly grown in Andhra Pradesh, Tamil Nadu, Orissa, Karnataka, West Bengal, Gujarat, Meghalaya, Maharashtra, Assam are some of the important states cultivates turmeric, of which, Andhra Pradesh alone occupies 35.0 % of the area and 47.0 % of production.Turmeric has been used in Indian systems of medicine for a long\ time. Recently, the demand for organic turmeric is growing rapidly in the global pharmaceutical market due to its anticancer properties. The turmeric of the northeast is known for its high Curcumin content and other quality parameters.
Climate and soil
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.The crop cannot withstand water logging and alkalinity.Like other crops, turmeric also requires deep tilth and heavy manuring for high yields.
Varieties of Turmeric
The cultivars suitable for NEH Region are Lakadong, Megha Turmeric 1
For organic turmeric production, a buffer zone of 25-50 feet is to be left all around from the conventional farm, depending upon the location of the farm.The produce from this zone shall not be treated as organic. Turmeric being an annual crop, the conversion period required will be 2-3 years, turmeric can be cultivated organically an as an intercrop or mixed crop with other crops provided all the other crops be grown following organic methods. The site selected should have good drainage facilities decomposed cattle manure or compost mixed with Trichoderma. The optimum spacing in furrows and ridges is 45-60 cm between the rows and 25 cm between the plants. At the time of planting apply 25 g neem cake per sqm mixed well with soil in each pit. A light irrigation is beneficial after planting followed by mulching.
Manuring and fertilizer application
Farmyard manure @ 15-20 t/ha along with 250 kg neem cake and 150 kg/ha rock phosphate or vermicompost @ 10 t/ha along with, 250 kg neem cake and 150 kg/ha rock phosphate is used for optimum turmeric yield. Integrated application of FYM 10t /ha and vermicompost 5t/ha along with 250 kg neem cake and 150 kg/ha rock phosphate is the best option for sustainable turmeric production. It is more beneficial if biofertilizers such as Azospirillum (Nitrogen fixer) and Bacillus (Phosphate Solubilizing Bacteria) is applied along with FYM or vermicompost.
Mulching of turmeric with paddy straw or green leaves or available weed biomass (Ambrosia spp., Eupatorium spp.) is an essential operation to enhance germination of rhizomes and to prevent soil erosion during heavy rains. This also helps to add organic matter to the soil and conserve moisture during the later part of the cropping season. The first mulching is to be done immediately after planting with green leaves @ 10 t/ha. Mulching may be repeated @ 5 t/ha at 45 and 90 days after planting after weeding and earthing up. Cow dung slurry may be poured on the bed after each mulching to enhance microbial activity and nutrient availability.
Turmeric is grown as a rainfed crop. However, irrigation has to be given when soil becomes dry. To loosen the soil, a light irrigation has to be given when soil becomes dry. A light irrigation may also be given 2-3 days before digging up the rhizomes. In water scarcity areas (like hilly terrain), suitable water conservation techniques (rain water harvesting) has to be adopted for providing life-saving irrigation.
Weeding has to be done thrice at 60, 90 and 120 days after planting depending upon weed intensity. Mulching reduces the weed problem.
Turmeric can be grown as an inter crop with chillies, Colocasia, onion, brinjal and cereals like maize, ragi, etc.
1.Leaf blotch- Leaf blotch is caused by Taphrina maculans and appears as small, oval, rectangular or irregular brown spots on either side of the leaves which soon become dirty yellow or dark brown. The leaves also turn yellow. In severe cases, the plants present a scorched appearance, and the rhizome yield is reduced. The disease can be controlled by spraying of copper oxy chloride 3 gm in 1 litre of water.
2.Rhizome rot-The disease is caused by Pythium Gra minicolumn or P. aphanidermatum. The collar region of the pseudostem becomes soft and water soaked, resulting in the collapse of the plant and decay of rhizomes. Selection of healthy rhizomes, soil solarization and incorporation of Trichoderma, seed treatment and soil application of biocontrol agents like Trichoderma or Pseudomonas multiplied in suitable carrier media such as coir pith compost, well rotten cow dung or quality neem cake may be done at the time of sowing and at regular intervals to keep the rhizome rot disease in check
Shoot borer-The shoot borer is the most serious pest of turmeric. The larvae bore into pseudo stems and feed on internal tissues. The presence of a borehole on the pseudo stem through which frass is extruded and the withered central shoot is a characteristic symptom of pest infestation. The adult is a medium sized moth with a wingspan of about 20 mm; the wings are orange yellow with minute black spots. Fully-grown larvae are light brown with sparse hairs. Spraying Neemgold in the ratio of 50 ml in 15 litres of water or neem oil 50ml in15 litres during July-October (at 21-day intervals) is effective against the shoot borer. The spraying has to be initiated when the first symptom of pest attack is seen on the inner most leaf.
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 nine 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. A good crop may be yielded around 18-20 t/ha.
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 rhizomes in water and drying in the sun. 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 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 lifting 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 a 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 in 5-7 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 a 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.
Preservation of seed rhizomes
Rhizomes for seed purpose are 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 litres of water to avoid storage losses due to fungi.
A good crop of turmeric may yield about 20-25 t/ha under organic production.
- Division of Natural Resource Management, ICAR-Research Complex for NEH Region
Umiam –793 103, Meghalaya.