Organic Turmeric Cultivation
Organic Turmeric Cultivation
Climate and soil
Turmeric requires a warm and humid climate. soils having natural drainage and irrigation facilities are the best. Turmeric cannot stand water stagnation or alkalinity.
Buffer zone
In order to cultivate turmeric organically a buffer zone of 25 to 50 feet shall be maintained if the neighbouing farms are non-organic. The produce from this zone shall not be treated as organic. Being an annual crop, turmeric requires a conversion period of two years.
Land preparation
While preparing the land, minimum tillage operations may be adopted. Beds of 15 cm height,1 m width and of convenient length may be prepared giving at least 50 cm spacing between beds. In the case of the irrigated crop, ridges and furrows are prepared and the rhizomes are planted in shallow pits on the top of the ridges. Spacing generally adopted is 45-60 cm between the ridges and 15-20 cm between the plants. Solarisation of beds is beneficial in checking the multiplication of pests and diseases causing organisms. The polythene sheets used for soil solarisation should be kept away safely after the work is completed.
Planting material
Carefully preserved seed rhizomes free from pests and diseases which are collected from organically cultivated farms should be used for planting. However, to begin with seed material from high yielding local varieties may be used in the absence of organically produced seeds. For sowing, both the mother - rhizomes and fingers are used. The fingers are cut into 4 - 5 cm long pieces, and the mother rhizomes are planted as such or split into two; each having at least one sound bud. The seed is sometimes sprouted under moist straw before sowing.
Varieties
A number of cultivars are available in the country and are known mostly by the name of the locality where they are cultivated. The cultivated varieties show considerable variation in size and colour of the rhizomes and curcumin content. More than 5 per cent curcumin content and lemon yellow, orange or orange yellow coloured turmeric powder are preferred in the international market. There are two dominant types of turmeric found on the world market: 'Madras', and 'Alleppey', both named after the regions of production in India. The orange-yellow flesh Alleppey turmeric is predominantly imported by the United States, where users prefer it as a spice and a food colorant. Alleppey turmeric contains about 3.5% to 5.5% volatile oils, and 4.0% to 7.0% curcumin. In contrast, the Madras type contains only 2% of volatile oils and 2% of curcumin. The Madras turmeric is preferred by the British and Middle Eastern markets for its more intense, brighter and lighter yellow color.
The Patna variety is noted for its deep colour. Of the two types cultivated in Maharashtra, 'Lokhandi' has bright coloured hard rhizomes and the other has light-coloured soft rhizomes. The popular commercial varieties in Andhra Pradesh are 'Duggirala' of Guntur and 'Tekurpeta' which has long, stout, smooth and hard fingers. 'Kasturi Pasupa' of the Godavari Delta, the 'Armoor' type of the Nizamabad area and the 'Chaya Pasupa' are the other important varieties of Andhra Pradesh. In Orissa important varieties cultivated are Roma, Suroma, Ranga and Rasmi. Lakadong variety of ginger is grown in Meghalaya and this variety is popular for high curcumin content of 5 to 5.05%.
Planting
At the time of planting 25 g powdered neem cake mix well with soil is applied in each pit taken at a spacing of 20-25 cm within and between rows. Seed rhizomes may be put in shallow pits and covered with well rotten cattle manure or compost mixed with Trichoderma (10 gm compost inoculated with Tricoderma). A seed rate of 1000 kg rhizomes is required for planting one acre of land. As an intercrop in a fruit-garden seed rate may be as low as 125 - 200 kg per acre. Turmeric can be planted during April-July with the receipt of pre monsoon showers.
Cultural practices
Mulching the beds with green leaves is an important practice beneficial to this crop when planting is done on raised beds. This helps to enhance germination of seed rhizomes, prevents wash off of soil due to heavy rains, adds organic matter to the soil and conserves moisture during the dry period. Care may be taken to include a mix of leguminous crops with leaves rich in nitrogen content, phosphorus content like Acalypha weed and potassium content like Calotropis as mulch. The first mulching is to be done at the time of planting with green leaves @ 4-5 tonnes per acre. It is to be repeated again @ 2 tonnes / acre at 50th day after planting. Cow dung slurry may be poured on the bed after each mulching to enhance microbial activity and nutrient availability. Weeding may be carried out depending on the intensity of weed growth. Such materials may be used for mulching. Proper drainage channels are to be provided in the inter rows to drain off stagnant water.
Manuring
Turmeric needs heavy manuring. Application of well rotten cow dung or compost from own farm @2-3 tonne /acre may be given as basal dose while planting rhizomes in the pits. In addition, application of neem cake @ 0.8 tonnes/ acre is also desirable.
Plant protection
The underlying approach for pest and disease management under organic production is based on a range of preventive and other management strategies to minimize the incidence of pests and diseases. Regular field surveillance, adoption of phyto sanitary measures combined with understanding the life cycles of both pest and its predators will allow decisions to be made regarding the need to intervene for managing the pest population.
Pests
If shoot borer incidence is noticed, such shoots may be cut open and larve picked out and destroyed. If necessary neem oil 0.5% may be sprayed at fortnightly intervals.
Diseases
No major disease is noticed in turmeric. Leaf spot and leaf blotch can be controlled by restricted use of Bordeaux mixture 1%. Application of Trichoderma at the time of planting can check the incidence of rhizome rot.
Harvesting and curing
The crop has to be harvested at the right maturity and is ready for harvesting in about 7 to 9 months after sowing depending upon the variety. The aromatic types mature in about 7 months, the intermediate types in about 8 months and the late types in about 9 months.
Usually the land is ploughed and the rhizomes are gathered by hand picking or the clumps are carefully lifted with a spade. Harvested rhizomes are cleaned of mud and other extraneous matter adhering to them. The average yield per acre is 8 -10 tonnes of green turmeric.
Fingers are separated from mother rhizomes. Mother rhizomes are usually kept as seed material. The green turmeric is cured for obtaining dry turmeric. Curing involves boiling of rhizomes in fresh water and drying it in the sun. No chemical should be used for processing. The cleaned rhizomes are boiled in copper or galvanized iron or earthen vessels, with water just enough to soak them. Boil till the fingers/mother rhizomes become soft. The cooked turmeric is taken out of the pan by lifting the troughs and draining the water into the pan itself. The same hot water in the pan can be used for boiling the next lot of raw turmeric which is already filled in the troughs. Alternatively, rhizomes may also be cooked using baskets with perforated bottom and sides. The mother rhizomes and the fingers are cured separately. The cooking of turmeric is to be done within 2-3 days after harvest.
The cooked fingers/mother rhizomes are spread on bamboo mats or cement floor under the sun for drying. The rhizomes are spread in 5-7 cm thick layers for desirable colour of the dried product. During night time the material should be heaped or covered. 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°C is also found to give a satisfactory product. In the case of sliced turmeric, artificial drying has a clear advantage giving brighter coloured product than sun drying which tends to suffer from surface bleaching. The recovery of dry product varies from 20-25% depending upon the variety and the location where the crop is grown. Dried turmeric has a poor appearance and rough dull colour outside the surface with scales and root bits. Smoothening and polishing the outer surface by manual or mechanical rubbing improves the appearance.
Manual polishing consists of rubbing the dried turmeric fingers on a hard surface. 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. The turmeric is also polished in power-operated drums. The colour of the turmeric always attracts the buyers. In order to impart attractive yellow colour, turmeric suspension in water is added to the polishing drum in the last 10 minutes. When the rhizomes are uniformly coated with suspension they may be dried in the sun.
Preservation of seed
Rhizomes for seed are generally heaped under the shade of trees or in well-ventilated sheds and covered with turmeric leaves. Sometimes, the heap is plastered over with earth mixed with cow dung. The seed rhizomes can also be stored in pits with sawdust. The pits can be covered with wooden planks with one or two holes for aeration.
Yield
The yield of pure crop varies from 8000 to 10000 kg per acre. Under exceptionally favourable conditions, viz. abundant manuring and copious irrigation it may be as high as 12000 kg per acre.
Regds
