The different factors that influence the growth of turmeric include:
Climate and soil
Turmeric is a tropical crop and is ideally grown in a warm, humid climate. The crop requires an annual rainfall of 2500 4000 mm for successful production. The initial growing period requires an average of 120-150 mm rainfall. During the later part of its growth, the crop requires some irrigation.
The crop is propagated through whole or split mother rhizomes. New advancements in the field include micro-propagation protocols for rapid multiplication.
The land must be ploughed at a level of 22-25 cm, about five to seven times. This must be followed by 2-3 plantings, during which all the weeds must be cleared. Well-rotten FYM or compost 40 t/ha should be mixed with the soil.
The planting of turmeric requires an exhaustive process that must be meticulously followed in order to achieve maximum yield:
- The field must be divided into beds of convenient length and must be planned in such a way so as to conserve moisture
- The beginning of April is the most ideal time to plant the crop and all preparation must be completed by the first week of May
- It must be ideally sown on ridges or raised beds to avoid water stagnation during the rainy season
- Harvests can begin in November / December and crop for the seeds must be selected and stored in underground pits
- April is the time when seeds start sprouting and it must be taken out from the pits plating
- The sprouts must be protected from mechanical injury
- The sprouts must be sown 3-5 cm deep at prescribed distances with the onset of the monsoon
Manures and fertilisers
Seed rhizomes can be treated with 0.3% Dthane M-45 and 0% Quinalphos prior to storage and again at the time of sowing. This will minimise both rhizome rot and furrows.
Other important manure additions include:
- A basal dose of FYM at 40 t/ha at the time of preparation
- A fertiliser requirement of 60:30:90 kg of NPK under rain fed conditions, applied in split doses
- The whole of P2O2 and half the dose of K2O as a basal dose
- N in 2 split doses after 45 days (60% of the recommended N)
- 90 days after planting, (40% of the recommended N) along with the remaining half dose of K20
Turmeric can be grown either as a rain fed crop in places like Kerala, Orissa and Tamil Nadu. In case of sowing it as an irrigated crop, 15-40 irrigations may be necessary at 7-10 day intervals.
Irrigation may be required if there is less moisture. The fields must be irrigated in September and October with a 10-14 day interval. A light irrigation at the time of harvesting can make the task relatively easy.
The field must be mulched with green leaves at 15 t/ha immediately after planting and must be repeated after 50 days, when the rhizomes have fully sprouted.
Weeding is normally done thrice, at 60, 120 and 150 days after planting, depending on the intensity of weed growth. Early weeding must be avoided and the earthing-up process is done 60 days after planting.
Inter-cropping and crop rotation
Turmeric can be grown under sparse shade and can be grown in coconut plantations, ginger or a mixed crop with red gram, chilli, colocasia, vegetables, maize and ragi.
In wetlands, the crop can be rotated with paddy, sugar cane, banana or vegetables.
In garden lands, turmeric can be rotated with red gram, maize, groundnut and sunflower.