Everything you need to learn about cultivating aonla organically. Learn about:- 1. Introduction to Aonla 2. Climate and Soil Required for Aonla Cultivation 3. Propagation 4. Training, Pruning and Canopy Management 5. Nutrient Management 6. Rejuvenation of Old and Unproductive Aonla Orchards 7. Harvesting and Yield 8. Organic Insect Pest and Disease Management 9. Varieties.
Contents:
- Introduction to Aonla
- Climate and Soil Required for Aonla Cultivation
- Propagation of Aonla Plants
- Training, Pruning and Canopy Management of Aonla Plant
- Nutrient Management of Aonla
- Rejuvenation of Old and Unproductive Aonla Orchards of Aonla
- Harvesting and Yield of Aonla Fruit
- Organic Insect Pest and Disease Management of Aonla
- Varieties of Aonla
1. Introduction to Aonla:
Aonla (Phyllanthus emblica syn. Emblica officinalis Gaertn.) belongs to family Phyllanthaceae. It is one of the important indigenous fruits of Indian subcontinent. Its fruits are rich source of vitamin-C. Besides its high nutritive value, it bears heavy crop every year. Aonla is cultivated in India in an area of 108 thousand ha and production was estimated to 1,266 thousand tons. It is largely cultivated in Uttar Pradesh (Azamgarh, Pratapgarh, Varanasi and Bareilly districts), Gujarat, Maharashtra and Karnataka.
2. Climate and Soil Required for Aonla Cultivation:
The climate ranging from hot tropical in plains to humid subtropical in mid hills is suitable for its cultivation. It is successfully raised in arid, semi-arid, coastal and warm temperature conditions. In India, it is now being successfully grown from near the sea coast to up to 1800 m altitude. A mature aonla tree can tolerate freezing as well as high temperature up to 46°C. Warm temperature is conducive for the initiation of floral buds; however, ample humidity is essential for initiation of fruit growth of dormant fruitlets during July-August.
Aonla is a hardy plant and can be grown successfully in red, sandy, sandy loam to clay soils. However, deep, fertile, sandy loam soil is ideal for aonla cultivation. It can also be cultivated in the marginal soils from slightly acidic to saline/sodic (pH 6.5-9.5, ESP upto 35 and EC upto 9.0 d/sm). Heavy soils or high water table areas are not suitable for its cultivation.
3. Propagation of Aonla Plants:
Aonla plants raised through seeds have slow growth, long juvenile period and do not produce true-to-type fruits. Therefore, only vegetatively propagated genuine planting material is preferred.
Rootstocks and Propagation Technique:
Six months to one year old seedlings raised from seeds of indigenous aonla trees are used as rootstock. Seeds from ripe fruits are kept in water overnight, then treated with Beejamrit or Pseudomonas Fluorescens@ 2-5 g per 1000g seed (or any other organic seed treating solution) and then sown either in seed trays or polybags and kept in polyhouse for quick germination and better success in budding/grafting.
The scion shoot should be selected from mother plants, which are prolific bearer and free from disease and pest incidence. Wood that is shedding or has already shed its bark and without leaves gives good results in grafting and budding. This practice encourages axillary buds to enlarge and greatly accelerates growth after grafting.
Aonla is successfully propagated through patch budding and it gives 60 to 90 per cent success during mid of May to September. Wedge/cleft grafting method of propagation is also appropriate technique for mass multiplication of aonla plants during winter. Under open conditions it gives best results in winter months but in polyhouse, wedge/cleft grafting gives good results throughout the year.
Planting Technique:
Land Preparation:
The land is prepared by usual ploughing, harrowing and levelling. A gentle slope is provided to facilitate proper irrigation and prompt drainage to avoid the harmful effects of water stagnation.
Plant Spacing:
Grafted or budded plants are planted at a distance of 7-10 m apart during July – August or February. Planting at a distance of 6m x 6m is quite suitable under organic management system and ideal to get good yield and quality fruits. In organic management high density planting having plant spacing of 6m x 4m or 5m x 5m should be avoided because narrow spacing’s do not allow intercrops, which is an essential component of organic management.
Aonla is generally planted in square system of planting, where plant to plant and row to row distances are kept same. In water scarce areas, plant to plant distance of 10 m x 10 m is recommended with 5% slope. Self-incompatibility in aonla is a common problem among various cultivars, hence two different varieties in alternate rows are planted for higher productivity. Planting with pollinizer varieties results in better yield. The best combination is NA 6 with NA 7, NA 7 with NA 10 and Kanchan (NA 4) with Krishna (NA 5).
Pit Filling:
The pits of 75cm x 75cm x 75cm size are dug 2 months prior to planting. Place the dugout topsoil to the right side of the pit and bottom soil to the left side of the pit. Allow the pit to expose to sun at least for two weeks before filling the pits to control soil borne insect pests.
In each pit, 3-4 baskets (25-40 kg) of well rotten farmyard manure, 500 g bone meal or 250 g rock phosphate powder and 1 kg neem cake are mixed with 50 per cent of topsoil and filled. In areas where micronutrient deficiency is established by soil tests, mix required quantity of micronutrient mineral in FYM during composting process. Filled pits are irrigated thoroughly if there is no rain.
Planting:
The budded/grafted plants with their earth balls should be taken and placed in the centre of the pit by excavating the soil to accommodate the earth ball and planting should be done during monsoon period. It is better to adjust the plant at same depth at which it was in the nursery. Light irrigation is given just after planting.
4. Training, Pruning and Canopy Management of Aonla Plant:
Aonla plant should be encouraged to develop a medium height tree. The young plants should be allowed to grow straight up to 0.75-1 m above the ground level, in order to provide good framework of the plant and then allowed to branch. Plants need to be trained to modified central leader system. Three to four branches with wide crotch angle, appearing in the opposite directions should be encouraged in early years. The unwanted branches are pinched off regularly.
In the subsequent years, 4-6 branches should be allowed to develop. Regular pruning of a bearing aonla tree is not required. As per growth habit, shedding of all determinate shoots encourages new growth in coming season. However, criss-cross, dried, dead, infested, broken or weak branches should be removed regularly. It will be advisable to spray Bordeaux mixture (4: 4: 500) to minimize infestation by diseases.
To make organic management system successful, it is important that whenever congestion is observed in plants it should be eliminated by opening the canopy, by adopting elimination of unwanted branches, thinning of branches and shoots, topping and side dressing of plants. This is important for better circulation of air and penetration of light. This will help also in minimizing the multiplication of pests and diseases.
Irrigation:
Aonla is a hardy tree. Hence, it requires less irrigation. No irrigation is required during rainy and winter seasons. However, irrigation at an interval of 10-15 days is required during dry summer (April-June), particularly in the early years of orchard establishment.
In bearing plantation, first irrigation should be given just after manure application (January-February) and it should be avoided during flowering (mid-March-mid-April) period. Among the various irrigation systems, basin irrigation is very common and drip irrigation is very effective.
Intercrops:
During initial planting years, when aonla plants are small, pulses and vegetables are ideal intercrops. Pulse-mustard, pulse-wheat, pulse-onion etc. can be taken up as intercrop in northern and eastern states. In southern states vegetables, mustard and medicinal plants are ideal choice.
In bearing orchards having irrigation facilities turmeric, ginger and arbi (Colocasia) are remunerative intercrops. Elephant foot yam can also be grown in two rows between two tree rows. Medicinal, herbal and aromatic plants are best suited intercrops in aonla. However the matching requirement of nutrients as well as their pest and disease management must be taken care of.
5. Nutrient Management in Aonla:
Bearing orchard with 10-12 tons/ha yield removes about 75-80 kg nitrogen, 25 kg phosphorus as P2O5 and about 70-90 kg potash as K2O. Out of this nearly 78% of N, 80% of P and 60% of K is returned to the soil in the form of fallen leaves, fruits, twigs, pruning’s etc. One cycle of green manure crop (sunhemp, mung bean, moth, cowpea or Sesbania) when incorporated into the soil adds up to 50-80 kg nitrogen.
Keeping the soil covered with green cover from July till February-March can ensure sustained biological activity in the soil. In rainfed areas where irrigation facilities are not available, and taking intercrops during winter is difficult, ensure that soil remains covered with biomass mulch for moisture conservation, sustained microbial activity in the soil and for effective weed control.
Fertilizer recommendations under conventional management also need to be considered for calculating organic nutrient requirements. Under conventional management, fully grown aonla tree is applied with 50 kg FYM, 1000g N, 500g P2O5 and 1000 g K2O. 50% of N and full dose of P and K is applied as basal dose during January-February before flowering. Remaining half of nitrogen is applied in July-August.
Keeping all these situations in mind two different nutrient management protocols have been worked out, one for rainfed dry areas, where only single harvest during November-January is possible and second for irrigated humid areas where irrigation is available (eastern India) and round the year harvests can be made (south India).
In case if intercrops are also being grown then apply necessary manures as basal dose needed for the growth of intercrops in specified areas at the time of field preparation for sowing. Soil and foliar application of liquid manures applied for aonla crop should also be applied on the intercrops.
6. Rejuvenation of Old and Unproductive Aonla Orchards:
Rejuvenation Technique:
The plants are headed back during December-January to the extent of 2.5-3.0 m above ground level. Before rejuvenation, branches are marked with white chalk by making ring around the branches. The selected branches should initially be cut from the underside (lower side) by giving at least 10 cm deep cut. Thereafter, the cutting should be done from upper surface of the branch. To avoid the fungal infection, the cut portion of tree is pasted with tree paste (cow dung + clay + sand (in equal part) + 100g CPP/25g BD 500) or simple fresh cow dung paste.
Several new shoots emerge on pruned branches after heading back but only a few shoots are retained at proper spacing and growing towards periphery of trees. Successive removal of unwanted shoots, considering the vigour and growing direction is important. Four to six shoots developing in outer directions on main limbs should be allowed to develop. Proper development of new canopy in horizontal direction should be kept in mind while practicing thinning of shoots.
The manure and compost should be spread in the basin and mixed well in the surface soil and immediately after that, give light irrigation. Half of the recommended nutrient doses need to be applied in January-February and rest of nutrients be applied in June-July. Care should be taken to manage the insect pest problems during this period, since these plants are prone to attack of pests and diseases and sometimes to wind damage.
During the first year, fruit production is less due to smaller canopy area and less number of hermaphrodite flowers on new growth. The yield continues to increase in succeeding years turning the unproductive trees to productive ones.
Intercropping in Rejuvenated Orchard:
During initial 2-3 years after rejuvenation, there is excellent opportunity for utilization of inter-space in the rejuvenated orchard. Vegetables like bottle gourd, okra, cauliflower, coriander, flowers like gladiolus and marigold are well suited for intercropping in rejuvenated aonla orchards.
In salt affected soils or marginal soils, intercropping of “Dhaincha (Sesbania)” for two years is beneficial for improving the physicochemical and biological properties of the soil. Mulching of rejuvenated trees also helps in their successful growth, flowering and fruiting.
Mulching with organic wastes, paddy straw, banana leaves, sugarcane trash etc. have shown promising results in aonla orchards. Mulching with these organic wastes also improves the organic matter content of soil and encourages earthworm population and other beneficial microbes in the rhizosphere. Among various mulching materials, black polythene and paddy straw proved best materials in respect of yield, number of fruits, nutrient status, and water use efficiency and soil microbial population.
7. Harvesting and Yield of Aonla Fruit:
Fully developed fruits are harvested on maturity. The aonla fruits are usually hand-picked or plucked with a locally made harvester by climbing the tree with the help of a bamboo ladder. The fruits should be harvested in the morning. The fruits should not be allowed to fall on the ground as the injured fruits can spoil other healthy fruits during packaging and storage. An aonla tree bears one to three quintal fruits per tree, with average productivity of 10-15 tons/ha.
Aonla fruits are graded into 3 grades. Large sized fruits (diameter above 4 cm) are utilized for preserves and candy, medium sized fruits for processing into other products, while small sized fruits are used mainly for making of Chavanprash, Trifla, etc.
Gunny bags and baskets are being used for packing of aonla fruits. However, CFB boxes are used for packing of aonla fruits for long distance transport. Aonla fruits can be stored for 6-9 days at room temperature. However, it could be stored up to 2 months at 5-7°C.
8. Organic Insect Pest and Disease Management of Aonla:
Pest management in organic farming cannot be addressed as stand-alone activity. It has to be the integral part of overall integrated management approach combining cultural, mechanical and biological strategies in first place and using botanical and organically acceptable chemicals only as last resort.
First and foremost strategy for organic pest management in aonla is creation and maintenance of diversity, which includes permanent diversity plantation on boundary and internal bunds, and seasonal diversity through intercrops, flowering plants and trap crops.
Permanent diversity plantation includes plantation of few trees of 3-4 different types of aonla varieties between main variety, nitrogen fixing plants like Gliricidia, Leucaena leucocephala etc. fruit plants like custard apple or ber etc. on borders and pesticidal value plants such as Adathoda, Ipotnea, Calotropis etc. randomly in between border plantation and aromatic grasses such as lemon grass on internal bunds.
Seasonal diversity includes intercrops such as legumes, pulses, turmeric, ginger, elephant foot yam, mustard, sunflower, medicinal, herbal and aromatic or dye plants. Some flowering trap crops such as marigold and Hibiscus can also be planted along the border.
Second strategy involves manipulation of cultural practices to ensure a balance in natural processes, which in turn keep the pests below the economical threshold limit.
Important cultural practices are:
1. Grow healthy crop – use of resistant cultivars and disease free planting stock,
2. Proper spacing, mulching and green manuring and adequate use of organic manures and proper irrigation. Do not adopt close spacing or high density planting.
B. Ecological and Cultural Strategies for Below Ground Pest Management:
1. Frequent growing of legumes in the orchard and its incorporation in the soil
2. Keep soil covered with living vegetation and or crop residue.
3. Adequate use of organic manures followed by biomass mulching and drenching with fermented dung-urine slurry (such as Jivamrit)
4. Frequent application of bio-fertilizers especially the mycorrhiza
C. Ecological and Cultural Strategies for above Ground Pest Management:
1. Ensure natural habitat and survival conditions for natural pest enemies such as pest predators, parasites and pathogens.
2. Do not uproot weed plants those are growing naturally and act as nectar source for natural enemies,
3. Due to enhancement of biodiversity by the flowering plants, numbers of parasitoids and predators (natural enemies) will increase due to availability of nectar, pollen and insects etc. The major predators are a wide variety of spiders, ladybird beetles, long horned grasshoppers, Chrysoperla, earwigs, etc.
4. Collect egg cards of beneficial insects for release such as Trichogramma, Chrysoperla, Telenomus etc. which are available from state Bio-control Labs.
5. Install pheromone traps, yellow/blue water pan and sticky traps
6. Set up light traps @ 4 traps/acre, 15 cm above the crop canopy for monitoring and mass trapping of insects. Light traps with exit option for natural enemies of smaller size should be installed and operate around the dusk time (6 pm to 10 pm) starting from the onset of rains till end of September (excessive use of light trap may be avoided as it kills all the insects including beneficial ones).
7. Grow flowering plants along the orchard border by arranging small plants towards the crop and taller plants towards border. Important insectary plants for intercrop also include mustard, sunflower, alfalfa, marigold, carrot, French bean, cowpea, maize, spearmint, peppermint, coriander Ocimum etc. After flowering these plants can be used as green manure/mulch.
Another important strategy is to keep monitoring the fields on weekly basis. Move around the field in a group, collect samples of leaves, flowers, twigs, fruits etc. and observe them for presence of insect pests, their egg masses, larvae, beneficial insects and symptoms of diseases. Sit with the group, analyze information and identify the problem. Keep a pictorial book/manual on important pests and diseases of aonla handy.
Compare the samples with the pictures given in the book and ascertain the problem. If unable to arrive at any decision then take the help of local agricultural officer for identification of insects and diseases. Enumerate pest: defender ratio. If pest defender ratio is 2:1 then no need to worry. If it increases above 2:1 then adopt necessary curative and control protocols.
9. Varieties of Aonla:
The most common varieties recommended are – Kanchan (NA 4), Krishna (NA 5), NA 6, NA 7, NA 10, NA 20 and Goma Aishwariya. Apart from these, there are some other varieties of aonla such as Laxmi-52 and BSR 1. Besides, Anand-1, Anand-2, Anand 3 have been selected as promising strains in Gujarat.