Turmeric (Curcuma longa) is native to the monsoon forests of south east Asia. It is a perennial herb to 1m tall with underground rhizomes. It belongs to the same family as ginger (Zingiberaceae) and grows in the same hot and humid tropical climate. The rhizome is a deep bright yellow colour and similar form to the ginger but slightly smaller. It produces tall, very beautiful, white flower spikes, if clumps are left undisturbed for a year. The flower is so attractive that it is worth growing for this alone. It requires a well-drained soil, frost-free climate and 1000 to 2000mm of rain annually or supplementary irrigation. It thrives best on loamy or alluvial fertile soils and cannot stand waterlogging. Heavy shade will reduce the yield but light shade is beneficial.
Turmeric Health Benefits and Uses:
Turmeric has a vast variety of medicinal uses. In traditional medicine, it used to treat liver ailments, ulcers, parasitic infections, skin problems, bruises, joint pain and inflammation, sprains, strains, cold and flu symptoms, as well as a general digestive aid. Scientific research shows that turmeric aids in breaking down liver toxins, strengthens the functioning of the gallbladder, aids in lipid (fat) metabolizing, and stops blood clotting. In general, it is a good anti-inflammatory agent. What is more, recent studies show that turmeric may help prevent colon, breast, lung and other forms of cancers.
Ground turmeric comprises 25% of curry powder and is used to give it a yellow colour. The harvested rhizomes are boiled and sun-dried for 7-8 days but can be used fresh. It is also used as a yellow food dye, replacing tetrazine. Leaves wrapped around fish flavour it during cooking. In Indonesia, the young shoots and rhizome tips are eaten raw.
Turmeric Production Guide
How to Plant Turmeric:
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 rainfed 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.
Preparation of land
The land is prepared with the receipt of early monsoon showers. The soil is brought to a fine tilth by giving about four deep ploughings. 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.
Manuring and fertilizer application
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. Fertilizers @ 60 kg N, 50 kg P2O5 and 120 kg K2O per hectare are to be applied in split doses. 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 coir compost (@ 2.5 t/ha) combined with FYM, biofertilizer (Azospirillum) and half recommended dose of NPK is also recommended.
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 and irrigation
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 irrigations are to be given in clayey soils and 40 irrigations in sandy loams.
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 mancozeb 0.2%.
Leaf spot is caused by Colletotrichum capsici and appears as brown spots of various sizes on the upper surface of the young leaves. The spots are irregular in shape and white or grey in the centre. Later, two or more spots may coalesce and form an irregular patch covering almost the whole leaf. The affected leaves eventually dry up. The rhizomes do not develop well. The disease can be controlled by spraying zineb 0.3% or Bordeaux mixture 1%.
The disease is caused by Pythium graminicolum or P. aphanidermatum. The collar region of the pseudostem becomes soft and water soaked, resulting in collapse of the plant and decay of rhizomes. Treating the seed rhizomes with mancozeb 0.3% for 30 minutes prior to storage and at the time of sowing prevents the disease. When the disease is noticed in the field, the beds should be drenched with mancozeb 0.3%.
Root knot nematodes (Meloidogyne spp.) and burrowing nematode (Radopholus similis) are the two important nematodes causing damage to turmeric. Root lesion nematodes (Pratylenchus spp.) are of common occurrence in Andhra Pradesh. Wherever nematode problems are common, use only healthy, nematode-free planting material. Increasing the organic content of the soil also checks the multiplication of nematodes. Pochonia chlamydosporia can be applied to the beds at the time of sowing @ 20 g/bed (at 106 cfu/g) for management of nematode problems.
The shoot borer (Conogethes punctiferalis) is the most serious pest of turmeric. The larvae bore into pseudostems and feed on internal tissues. The presence of a bore-hole on the pseudostem 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 malathion (0.1%) at 21 day intervals during July to October is effective in controlling the pest infestation. The spraying has to be initiated when the first symptom of pest attack is seen on the inner most leaf.
The rhizome scale (Aspidiella hartii) infests rhizomes in the field (at later stages of the crop) and in storage. Adult (female) scales are circular (about 1mm diameter) and light brown to grey and appear as encrustations on the rhizomes. They feed on sap and when the rhizomes are severely infested, they become shrivelled and desiccated affecting its germination. Treat seed material with quinalphos (0.075%) (for 20-30 minutes) before storage and also before sowing in case the infestation persists. Discard and do not store severely infested rhizomes.
Adults and larvae of leaf feeding beetles such as Lema spp. feed on leaves especially during the monsoon season and form elongated parallel feeding marks on them. The spraying of malathion (0.1%) undertaken for the management of shoot borer is sufficient to manage this pest.
The lacewing bug (Stephanitis typicus) infests the foliage causing them to turn pale and dry up. The pest infestation is more common during the post monsoon period especially in drier regions of the country. Spraying dimethoate (0.05%) is effective in managing the pest.
The turmeric thrips (Panchaetothrips indicus) infests the leaves causing them to roll, turn pale and gradually dry up. The pest infestation is more common during the post monsoon period especially in drier regions of the country. Spraying dimethoate (0.05%) is effective for the management of the pest.
Turmeric readiness for harvest is indicated by the drying of the plant and stem, approximately 7 to 10 months after planting, depending on cultivar, soil and growing conditions. The rhizome bunches are carefully dug out manually with a spade, or the soil is first loosen with a small digger, and clumps manually lifted. It is better to cut the leaves before lifting the rhizomes. Rhizomes are cleaned from adhering soil by soaking in water, and long roots are removed as well as leaf scales. Rhizomes are then further cured and processed, or stored for the next year’s planting.