Ginger (Zingiber officinale Rosc.) is a herbaceous perennial crop usually grown as an annual for its rhizomes. It is a valuable cash crop and widely used in food, beverage, confectionery and medicine. It is marketed in different forms such as raw ginger, dry ginger, ginger powder, ginger oil, ginger oleoresin, ginger ale, ginger candy, ginger beer, brined ginger, ginger wine, ginger squash, ginger flakes etc. Though it is also cultivated in Jamaica, Nigeria, Sierra, Leone, Brazil, China, Japan, and Indonesia, India still is the largest producer of dry ginger; It is cultivated in almost all the states of India.
The Major ginger growing states are Kerala, West Bengal and North Eastern Region. About three lakhs tones of ginger are being produced annually from 47,641 ha land, and the northeast region is emerging as India’s organic ginger hub. This region is one among the highest ginger productivity zone in the world. The ginger of the region is known for its quality (less fibre).It produced from northeastern states are reported to have higher oil and oleoresin content than ginger from other parts of the country. Dry ginger has a good demand abroad, and India is the largest exporter of dry ginger.
Soil and climate
It is cultivated in different types of soils, provided sufficiently well-distributed rainfall or irrigation and adequate drainage facilities are available. The ideal soil for ginger cultivation is sandy or clay loam or red loam or lateritic loam with good drainage and aeration. A deep friable loam rich in humus is ideal for cultivation. However, being an exhaustive crop, it is not desirable to grow ginger in the same site year after year. Ideal pH range of ginger is 5– 7.5. It grows well in a humid climate and is cultivated from sea level up to altitudes of about 1500 m above MSL.
However, the optimum elevation for its successful cultivation is in the range of 300-900 m.It can be grown both, under rainfed and irrigated conditions. Moderate rainfall at sowing time till the rhizomes sprout, followed by fairly heavy and well-distributed showers during the growing period and dry weather about one month before harvesting are optimum requirements for its successful cultivation.
Varieties of Ginger
Cultivars suitable for NEH Region are Nadia, Maran, China, Varada, Himgiri, Mahima, Goru bathane, Rajetha and Rio-de-Janeiro.
For organic ginger 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. Ginger being an annual crop, the conversion period required will be 2-3 years, it can be cultivated organically an as an intercrop or mixed crop with other crops provided all the other crops are grown following organic methods. The selected site should be well drained and preferably the pace where it is not grown earlier.
The land has to be ploughed 4-5 times or dug thoroughly with receipt of early summer showers to bring the soil to medium tilth. Beds of 1m width, 15cm height and of convenient length are prepared with an interspace of 30-50 cm in between beds. Solarization of beds for 40 days with transparent polythene sheets is recommended in areas prone to rhizome rot and nematode infestation. In valley region or high rainfall area, proper drainage channels should be provided in the inner- rows to drain off the stagnant water.
Seed Selection and treatment
Carefully preserved seed rhizomes, free from pests and disease, 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 material. Seed rhizomes should be kept in the sun for 20-30 days before planting. Dipping the rhizome sets in cow urine for half an hour is also beneficial.
The optimum size of the rhizome is about 50 g. The seed should be selected during October – November during harvesting and the infested rhizome should be removed. The seed selected from a locality where pest and disease problems were not observed gives higher yield. Remove the infested plant with rhizome rot from the field selected for seed production. Rhizome treatment with bioorganic GF1 @ 30 ml/l has been found effective in managing soft rot of ginger and improving yield by more than 20 %.
Use of chemical fungicides for rhizome treatment is strictly prohibited in organic ginger production. To control the soft disease, slurry of Trichoderma viridae @5 g/kg of seed is prepared, and seeds are treated with the slurry. Acacia gum may be applied to the slurry as sticker material. Trichoderma spray or drenching 1 % at 15 days interval is also useful for controlling ginger rot. Before planting, the rhizome bits are then soaked in the slurry for 30 minutes and then dried in airy place under shade.
The planting season for ginger is from March-April, with the onset of the monsoon. The crop duration is around 8-9 months (April/May to December/ January). It is planted in rows, 30 cm apart at distances of 20-25 cm within the row. Bits of seed-rhizomes weighing 30- 50 g each, 3-5 cm in length and having at least one bud are planted at the given spacing. The rhizome used for seed should be true to type and free from disease. About 2.0 t rhizome/ha is required for planting one-hectare land.
While planting, seed rhizomes mixed with well rotten cattle manure or compost mixed with Trichoderma (10 g of compost inoculated with Trichoderma) may be put in shallow pits and covered with a thin layer of soil and levelled. The beds are covered with leaf mulch as protection against the sun and heavy rains and for the consequent enrichment of organic matter in the soil. Farmyard manure can also be used as mulch.
Cropping system and pattern
Different types of cropping systems are followed for ginger cultivation in the region. Generally, farmers prefer mono cropping of ginger. However, they also practice mixed cropping with maize, chilli, soybean, brinjal, papaya, cucumber, pumpkin, yam, tree tomato, tapioca and different types of leguminous crops in jhum. Sometimes they intercrop ginger with maize and pineapple. Ginger can tolerate shed and hence suitable for agroforestry based farming system models. The ginger should be rotated with other crops such as legumes, cereals etc. for higher productivity and prevention from disease problems.
Mulching ginger beds with green leaves is an important operation in ginger. Apart from being an organic manure, it helps in soil and water conservation. Mulching may be done with green leaves thrice in ginger, once immediately after planting @ 10 to 12 tonnes /ha to enhance germination, increase organic matter, and conserve soil moisture and prevent washing of soil due to heavy rains. It is repeated @ 4-5 tonnes /ha at 40th and 90th day after planting preferably at the time of weeding, hoeing and earthing up.
Use of Lantana camara and Vitex negundo leaves as mulch may reduce the infestation of shoot borer. Cow dung slurry or liquid manure may be poured on the bed after each mulching to enhance the microbial activity and nutrient availability. Two weedings are generally given to the crop. The first weeding just before the second mulching and repeated depending on the intensity of weed growth. The weeded material may be used for mulching. If necessary weeding is to be repeated a third time. Plants are earthed up once or twice with sufficient soil from inter row spaces for covering the rhizome. Proper drainage channels are to be provided in the inter rows to drain off the stagnant water.
Mulching conserves soil moisture by checking evaporation loss. Bunds are constructed to prevent soil erosion and to retain the topsoil, and proper drainage channels are provided to drain off the stagnant water. Seasonal legumes are also grown along with ginger to suppress weed growth, minimize soil erosion and enhance soil fertility.
Being exhaustive crop, it requires heavy manuring. About 20-25 t FYM/ha is required for a good yield of ginger. However, integrated application of 10 t FYM, 5 t vermicompost, 5 t green leaf together with 250 kg neem cake and 150 kg rock phosphate per hectare is optimum for organic ginger production and sustaining soil health. Well, rotten cow dung or compost has to be applied either by broadcasting over the beds and incorporating to soil before planting or applied in the pits at the time of planting. Application of neem cake at the time of planting helps in reducing the incidence of rhizome rot disease/nematode and increase the yield.
Shoot borer is the major pest infesting ginger. Regular field surveillance and adoption of phytosanitary measures are necessary for pest management. It appears during July -October period. Spot out the shoots infested by the borer and cut open the shoot and pick out the caterpillar and destroy them. Spray neem oil (0.5%) at fortnightly intervals if found necessary. Light traps will be useful in attracting and collecting the adult moths.
Soft rot or rhizome rot is a major disease of ginger. While selecting the area for its cultivation care should be taken to see that the area is well drained as water stagnation predisposes the plants to infection. Select seed rhizomes from disease free areas since this disease is seed borne. Solarization of soil done at the time of bed preparation can reduce the fungus inoculum.
However, if the disease is noticed, the affected clumps are to be removed carefully along with the soil surrounding the rhizome to reduce the spread. Trichoderma (1%) may be applied at the time of planting and subsequently as foliar spray or drenching if necessary. Restricted use of Bordeaux mixture (1%) in disease prone areas may be made to control it as spot application.
Harvesting and curing
The crop is ready for harvesting in about 8 to 9 months depending on the maturity of the variety. When fully mature the leaves turn yellow, and the pseudo-stems begin to dry. Rhizomes are lifted either with a digging-fork or with a spade. They are cleaned of roots and adhering soil particles. The removal mother rhizome is practised by farmers in about five months duration of the crop. Such practice increases the incidence of disease in the crops and hence, should be avoided to the extent possible.
The green ginger is soaked in water to facilitate the removal of the skin. The skin is scraped off with pieces of sharpened bamboo. The scraped produce is washed and dried in the sun for 3 or 4 days and hand-rubbed. It is again steeped in water for two hours, dried and then rubbed to remove all the remaining bits of the skin. Sun-drying also bleaches the produce.
Peeling should be done with great care and skill. The essential oil which gives ginger the aromatic character is present in the epidermal cells and hence excessive or careless scraping will result in damaging these cells leading to the loss of essential oils. Steel knives are not used as they are found to stain the produce. Storage of dry ginger for longer periods is not desirable. The yield of dry ginger is 15-25 percent of the fresh ginger depending upon the variety and location where the crop is grown. Burning of sulphur for processing ginger is not allowed.
Preservation of seed
The rhizomes to be used as seed material should be preserved carefully. Indigenous practices like spreading layers of leaves of Glycosmis pentaphylla being followed by farmers can very well be adopted for this purpose. To get good germination, the seed rhizomes are to be stored properly in pits under shade. For seed material, big and healthy rhizomes from disease-free plants are selected immediately after harvest. For this purpose, healthy and disease-free clumps are marked in the field when the crop is 6 – 8 months old and still green.
Seed rhizomes are stored in pits of convenient size made in the shed to protect from the sun and rain. Walls of the pits may be coated with cow dung paste. Seed rhizomes are stored in these pits in layers along with well-dried sand/saw dust (i.e. put one layer of seed rhizomes, then put 2 cm thick layer of sand/saw dust). Sufficient gap is to be left at the top of the pits for adequate aeration.
Seed rhizomes in pits need inspection once in twenty days to remove shrivelled and disease affected rhizomes. Seed rhizomes can also be stored in pits dug in the ground under the shade of a tree provided there is no chance for water to enter the pits. In some areas, the rhizomes are loosely heaped over a layer of sand or paddy husk and covered with dry leaves in thatched sheds.
Ginger become ready for harvesting after 8-9 month of sowing (in December) when the leaves start yellowing and drying. The average yield of the Ginger rhizome is estimated at about 7 to 12 tonnes per hectare. The recovery of dry ginger varies from 16 – 25 per cent.
- Division of Natural Resource Management, ICAR-Research Complex for NEH Region, Umiam-793103, Meghalaya.