Amla or aonla (Emblica offecinalis), known in English as Indian gooseberry, has diverse use in ayurvedic medicines and health tonics such as chavanprash and triphala.
Widely grown in BAIF Wadi plots in Rajasthan, in a semiarid zone, amla has proved to be a good source of income for poor tribal families. Amla is one of the richest natural sources of Vitamin C (it contains 650mg of Vitamin C per 100 gm of pulp). The fruit also contains a high amount of salt, carbohydrates, phosphorous, calcium, iron, other vitamins and amino acids. Due to high market demand, the fruit is being cultivated on a commercial scale and growers are fetching high returns.
The main commercial varieties of amla are as follows:
Banarsi : This is an early fruiting variety. Fruits are oval with white and greenish marks. Fruits are large, and mainly used for making `murabba’.
Francis (Hathijhool): A vigorous, mid-maturing variety. Fruits are yellowish in colour. Affected by internal necrosis.
Chakaiya : A late maturing variety. Production is high. Also used as polleniser for other varieties.
Kanchan (NA-4): A selection of seedling of Chakaiya. It is a heavy and regular bearer. Fruits are of medium size with high fibre content, so mainly preferred for pulp and manufacturing various products.
Krishna (NA-5): A selection from Banarsi. Early maturing variety with fruits of 40-50 gm, attractive, round with compressed distal ends with red spots. Pulp is fibreless. Production more than Banarsi.
Narendra-6 (NA-6): A mid maturing variety; a selection from Chakaiya. Fruits are medium to large sized , attractive and shining with low fibre content. Trees are heavy fruit bearers and fruits are suitable for making candy, preserve, sweets, jam and sauce.
Narendra-7 (NA-7): A selection from Francis. Fruits mature in mid season, are medium to large, with conical apex and free from necrosis. Fibre content is a little higher than in NA-6. A precocious and prolific bearer. Ideal for making chawanprash, chutney, pickle, jam and squash.
Narendra-9 (NA-9): An early variety with medium spreading habit. Vit-C content is high in comparison to other varieties. Fruits mature from mid October to early November.
Narendra-10 (NA-10): A selection from Banarsi. Fruits are early maturing, large-sized and flattened. Heavy bearer and suitable for pickling and dehydration.
Climate and soil requirements
Amla is very hardy and can be grown in different agro-climatic conditions. A well grown tree can withstand temperatures from 00C to 460 C. It can be grown in variable soil conditions ranging from pH 6.5 to 8.5. It is a tree of the tropics but nowadays, it is being successfully cultivated in subtropical and subtemperate climatic zones.
Amla was usually propagated by seeds. But seedling plants bear poor quality fruit with small size and have a long juvenile period. Grafted plants are preferred. Amla can be propagated by different vegetative methods such as cleft grafting and patch and ring budding. Best results have been achieved through patch budding (80-100%).
Raising rootstock (mother seedling)
For raising rootstocks, the fruits are harvested in Jan-Feb and dried to take out the seeds For getting 1kg of seeds, 1 quintal of amla is needed. The seeds are graded by soaking in water. Floating seeds are discarded and sunken seeds are dried and kept for sowing. For better germination, collected seeds are treated with 200-500ppm Gibberelic acid.
Treated seeds should be shown on raised beds during March-April. They can also be sown in polybags for better handling. Seedlings of late sown seeds do not reach buddable size in the same season. Seeds sown during March/April germinate within 2 weeks and seedlings of about pencil thickness are obtained after 90-100 days; these can be used for budding.
The scion should be selected from the mother plants that are prolific and regular bearers, and show low incidence of pest and disease.
Patch and modified ring budding techniques are used for commercial propagation.
The bud from the selected scion wood is removed in the form of a rectangular patch measuring 2-3cm. Similar type of patch is removed from the stock wood.
he scion bud is placed on stock wood and tied with the help of grafting tape or polyethylene strips.
When the bud starts sprouting, the stock wood is headed back just above bud.
Amla is planted at a distance of 10 x 10 to 12 x 12m in fertile soil. In degraded and poor soils, planting is done with a spacing of 8 x 8m. Pits of 1x 1x 1m are dug in the month of May and left open for at least one month for disinfection by sun rays.
Pit filling mixture
Dug pits should be filled with following mixture:
- 1kg bone meal
- 1kg neem cake
- 1kg single super phosphate
- 100 gm Endosulphan (4% dust)
- 30-40 kg dry leaves
- 30-40 kg farm yard manure
Pits are filled and irrigated to settle the soil. Basins are prepared according to slope of land, to control runoff and to ensure percolation of water inside pits.
Planting can be done from July to September during the monsoons. Plantation in Jan-Feb has also given good results in Udaipur district of Rajasthan, when plants were planted in their dormant condition.
Plant should be planted by removing as much soil as to accommodate the earth ball. Best results are obtained by placing the earth ball at the depth at which it was in nursery. The earth ball is covered with soil and light irrigation is given.
Training and pruning
Amla trees have heavy fruiting and as a result limb breakages occur. In order to overcome this problem, in the initial years, the plant is pruned that it develops a strong framework of scaffold branches. The plant is allowed to grow a single stem up to a height of 1m.
One primary branch, 4-6 well-spaced lateral branches in all directions and tertiary branches on laterals are encouraged. Criss-crossing branches are removed. Branches going downward or towards the tree are removed.
In grafted plants, there are sprouts from the mother seedling (rootstock) which should be removed regularly.
During the dormant season all dead, diseased and weak branches should be removed and the plant should be fertigated and irrigated.
Fertilisation and irrigation
Regular application of manure and fertilisers enables production of a good crop every year.
A 1-year old plant should be provided with 10kg of farmyard manure (FYM), 100gm nitrogen, 50gm phosphorous and 75gm potash. This dose should be increased every year in the same proportion up to the age of 10 years; thereafter same dose is continued.
FYM should be applied in January-Feb whereas half dose of nitrogen and potash and full dose of phosphorous is also given at the same time, before flowering. The remaining dose of nitrogen and potash should be given in August-end.
Fertiliser and manure are provided by spreading it throughout the plant basin. Good results can be obtained by applying fertiliser doses in trenches under the canopy.
In the initial years, plants are watered regularly at an interval of 10-15 days in summer and 20-30 days in winter.
Under rainfed conditions, pot irrigation using pitchers (ghed) has been found beneficial during the dry months. Two pitchers are placed in plant basin in the root zone in Nov-Dec and filled regularly at an interval of 10-15 days.
In a fruit-bearing orchard, adequate irrigation is provided after manuring and fertiliser application but irrigation is checked during flowering. Irrigation is given 15-20 days after fruits have set. Waterlogging is to be avoided during the monsoon.
Regular weeding and hoeing should be done to reduce competition from weeds. Young trees should be protected from direct sunlight, hot winds and frost in winters by installing tree guards in the first 2-3 years.
In fruit-bearing orchards, mulching during hot months is advisable to reduce moisture loss. Dry leaves, straw or plastic film can be used as mulching material.
Cropping between fruit trees
Cultivation of crops in spaces between trees is possible in the initial years. Farmers can get additional income and cropping will provide soil cover, which increases soil fertility.
In the initial years, gram, pea, pigeon pea, lentil, wheat and other pulses can be grown. Among fruits crops, guava, karondha and phalsa can be grown. Under assured irrigation, flowers such as gladioli, tuberose and marigold can be grown successfully.
Pests and their control
Shoot gallmaker (Betousa stylophura) Attacks during monsoon on onset of new growth.
The young insects penetrate from apical portion of the shoot after the monsoon and feed inside the tissue, changing into galls. Growth of shoot is hampered and few lateral shoots develop below galls.
Galls with insects are removed by cutting and destroyed. Spray of monocrotophos 0.05% during rainy season helps in control.
Bark eating caterpillar (Inderbela tetraonis) Attacks in April at initiation of new growth after dormancy.
It makes tunnels inside the bark and feeds there. As a result, the shoots become hollow and often break due to strong winds.
Plug the holes by injecting kerosene oil. Spray 0.05% Endosulfan. Plug the holes with mud after cleaning.
Diseases and their control
Fruit rot Caused by penicillium fungus. Incidence of the disease is more during fruit maturity and during storage and transportation.
Water-soaked spots on fruits, which swell and turn yellow, brown and finally black. The spots increase in size and show rotting symptoms.
Fruits showing initial symptoms should be harvested and treated with 0.1 - 0.5 % borax or NaCl. During storage and transportation, infected fruits should be separated.
Leaf rust Caused by fungus Ravenillia emblice.
Brown pustules appear on both fruits and leaves and finally these become dark brown to black. Affected fruits and leaves drop prematurely.
Spray of Diathane M-45/ Indofil M-45 0.3% (3 gm/l) twice has been found effective. First spray is given in the first week of September and second after 15 days.
Internal necrosis (physiological disorder)
It is not apparent from outside initially and starts from seed. The tissue turns brown and later on black and disease spreads toward the epicarp. This causes a lot of loss in production
0.6% borox is sprayed from Sept to Oct, thrice at an interval of 10-15 days.
Harvesting and yield
In general, amla fruit is harvested when the colour of seed turns black. For better storage and marketability, fruits are harvested according to variety. Early varieties such as NA-9, NA-10 and Banarsi should be harvested in the last week of November whereas mid maturing varieties such as Francis, NA-6 (Amrit) and Neelam (NA 7) are harvested in December. A late variety such as chakaiya is harvested in late January.
Budded plants start bearing from year 4 and attain full bearing in 8-10 years, giving a production of 80-100kg fruits/ tree.
To get maximum prices, fruits are graded according to size and texture.
`A’ grade fruits weigh 40-60gm, are large in size, without any blemishes and have clear, shiny skin.
`B’ grade fruits are medium-sized, weighing 30-40gm, with clear and shining skin.
C grade fruits are small with a few blemishes.
D grade fruits are discarded during grading and used for drying.
Due to its high astringency, amla fruit is not directly consumed but a number of processed product are made. The main products are ' murabba', pickle, jam, candy, squash and supari. Due to high Vit-C content and medicinal property, the fruit is used in a number of ayurvedic medicines such as chavanprash, triphala, bramhi rasayan and digestive churan.
Amla is also used for making ink, hair dye, hair shampoo, hair oil, etc.
Leaves of amla can be used as animal feed after fruit is harvested. Amla wood can be used as fuel and old branches with good girth can be used as timber for furniture and building material.
Around 11 to 14 quintals of fruits can be obtained per acre, giving a net income of Rs 10,000 to 15,000 per acre, at 2008 prices.