Organic cultivation of Ginger

Ginger is cultivated in many states in India. Dry ginger has good demand abroad especially in the Middle East markets. India is the largest exporter of dry ginger.
Ginger is a tropical crop adapted for cultivation even in regions of subtropical climate such as the high ranges. This crop thrives best in well drained friable loamy soils rich in humus. Being an exhaustive crop, it may not be desirable to grow ginger in the same field year after year. Therefore, it is essential to convert the whole farm as organic with ginger as one of the crops in rotation. The crop cannot withstand water logging and hence soils with good drainage are preferred for its cultivation. In order to cultivate ginger organically an isolation distance of 25m wide is to be left on all around from the conventional farm. The produce from this isolation belt shall not be treated as organic. Being an annual crop, the conversion period required will be two years. Ginger can be cultivated organically as an inter or mixed crop provided all the other crops are grown following organic methods. It is desirable to include a leguminous crop in rotation with ginger. Ginger-banana-legume or ginger-vegetable-legume can be adopted.

Sources of planting material

Carefully preserved seed rhizomes free from pests and diseases, which are collected from organically cultivated farms can be used for planting. However, to begin with seed material from high yielding local varieties may be used in the absence of organically produced seed. Seed rhizomes should not be treated with any chemicals.

Preparation of land and planting

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. Solarisation of the beds is beneficial in checking the multipli­cation of pest and disease causing organisms. The polythene sheets used for soil solarisation should be kept away safely after the work is completed.
At the time of planting, apply 25 g powdered neem cake and mix well with the soil in each pit taken at a spacing of 20-25 cm within and between rows. Seed rhizomes may be put in shallow pits and mixed with well rotten cattle manure or compost mixed with Trichoderma (10 g compost inoculated with Trichoderma).

Cultural practices

Mulching the ginger beds with green leaves is an essential operation to enhance germination of seed rhizomes and to prevent washing off soil due to heavy rain. 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 with green leaves @ 10 - 12 t/ha at the time of planting. It is to be repeated @ 5 t/ha at 40th and 90th day after planting. Use of Lantana camara and Vitex negundo 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 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

Application of well rotten cow dung or compost @ 5-6 t/ha may be made as a basal dose while planting the rhizomes in the pits. Enriched compost giving a start to phosphorus and potassium requirements may be highly useful. In addition, application of neem cake @ 2 t/ha is also desirable.

Plant protection

Diseases

Soft rot or rhizome rot caused by Pythium aphanidermatum is a major disease of ginger. While selecting the area for ginger cultivation care should be taken to see that the area is well drained as water stagnation pre-disposes the plants to infection. Hence provide adequate drainage. Select seed rhizomes from disease free areas since this disease is also seed borne. Solarisation 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 may be applied at the time of planting and subsequently if necessary. Restricted use of Bordeaux mixture (1 %) in disease prone areas may be made to control it.
The bacterial wilt caused by Pseudomonas solanacearum can be managed by treating the seed rhizomes with streptocycline (200 ppm) for 30 minutes and shade drying before planting. In case the disease is noticed in the field, a uniform drenching of all the beds with Bordeaux mixture (1 %) may be made.
Regular field surveillance and adoption of phytosanitary measures are necessary for pest management. The shoot borer Conogethes punctiferalis is the most important pest of ginger. It appears during July-October. period. Spot out the shoots infested by the borer. Cut open the shoot and pick out the caterpillar and destroy. Spray neem oil (O.5%) at fortnightly intervals if found necessary. Light traps will be useful in attracting and collecting the adult moths.

Harvesting and post harvest operations

The crop is ready to harvest in about eight to ten months depending upon the maturity of the variety. When fully mature leaves turn yellow and start drying up gradually. Clumps are lifted carefully with a spade or digging fork and rhizomes are separated from dried leaves, roots and adhering soil. The average yield of fresh ginger per hectare varies with varieties ranging from 15 to 25 tonnes.
For making vegetable ginger, harvesting is done from the 6th month onwards. The rhizomes are thoroughly washed in water twice or thrice after harvest and sun-dried for a day.
For preparing dry ginger the produce is kept soaked in water overnight. Rhizomes are then rubbed well to clean them. After cleaning, rhizomes are removed from the water and the outer skin is removed with a bamboo splinter or wooden knife having pointed ends. Iron knife is not recommended, as colour will be faded. In order to get rid of the last bit of the skin or dirt, the dry rhizomes are rubbed together. The peeled rhizomes are washed and dried in the sun uniformly for one week. Rhizomes are to be dried to a moisture level of 11 % and they are stored properly to avoid infestation by storage pests. Storage of dry ginger for longer periods is not desirable. The yield of dry ginger is 16-25 per cent 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 rhizomes

The rhizomes to be used as seed material should be preserved carefully. The indigenous practices like spreading layers of leaves of Glycosmis pentaphylla called in Malayalam 'panal' being followed by farmers can very well be adopted for this purpose. In order to get good germination, the seed rhizomes are to be stored properly in pits under shade. For seed materials, 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 inside 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 or saw dust (i.e. put one layer of seed rhizomes, then put 2 cm thick layer of sand or saw dust). Sufficient gap is to be left at the top of the pits for adequate aeration. The pits can be covered with wooden plank with one or two small holes for aeration. Seed rhizomes in pits need inspection once in twenty days to remove shriveled 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 a thatched shed.