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Canopy managemnt in aonla
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- 2. CONTENTS Introduction Uses Origin and disribution Plant description Flowering behaviour Canopy management-general aspects Training and pruning in aonla Production constraints Rejuvanation Top working Intercropping,nutrient management,irrigation Referances
- 3. INTRODUCTION Amla, aonlaor Indian gooseberry (Emblica officinalis) is an indigenous fruit to the Indian subcontinent. Owing to hardy nature, suitability to various waste lands, high productivity/unit area (15-20tons/ha), nutritive and therapeutic value, amla is becoming more and more commercially important with every passing year. Amla fruits are a very rich source of vitamin C having a good quantity of ascorbic acid content varying from 0.9 to 1.3 percent. The fruits have pungent and cooling effect .It helps in easy discharge of urine and act as laxative. This is the second highest among all the cultivated fruits. This fruit has a great value among indigenous medicines. It is acrid, cooling, refrigerant, diuretic . Dried fruits have been reported to be useful in health complications like haemorrhages, diarrhoea, dysentery, anaemia, jaundice, dyspepsia and cough. Trifala and Chyavanprash are well known indigenous medicines in Ayurvedic system using amla fruits.
- 5. ORIGIN AND DISTRIBUTION Aonla is originated in central India. From India it spread to neighbouring countries such as China, Cylon and Malaysia. In India it’s commercial cultivation is very common in Uttar Pradesh. Its intensive plantation is being done in the salt- affected areas of Utter Pradesh. Aonla cultivation is spreading rapidly in the semi-arid regions of Maharashtra, Gujarat, Rajasthan, Andhra Pradesh, Karnataka, Tamil Nadu and Himachal Pradesh. Though aonla is not commercially cultivated in the North Eastern, it is commonly found either in homestead or growing in wild which indicates its adaptability.
- 6. PLANT DESCRIPTION Undersub-tropical conditions, tree is deciduous in nature. The bark of the trunk is grey in colour. The tree is spreading in nature. Full grown tree can have a height of 8- 9 meters depending upon the soil fertility. It is monoecious plant having male and female flowers separately on the same panicle. Proportion of male flowers is very high. Male flowers appear in clusters in leaf axils and female on the upper end of few branchlets. Aonla has drooping habit of branches. The bearing is heavy on tender and lengthy shoots. Due to fruit weight branches tend to break.
- 7. FLOWERING BEHAVIOUR Aonlabears two types of flower, male and female which appear on branchlets in late spring. When hot winds blow, fruit set is often a problem. It is observed that flower bud differentiation in Banarasi cultivar takes place in the first week of March. The flowers commence opening from the last week of March and the blooming period lasts for 3 weeks. Male flowers appear in clusters on the axil of leaf all over the branchlet, while female flowers on the upper end of a few branchlets only. The maximum number of male flowers opens between 6 and 7 pm and dehiscence of anthers occurs soon or about 10-15 minutes after anthesis. The female flowers open gradually and it takes 72 hours to open completely. The stigma becomes receptive on the third day of anthesis. Aonla is pollinated mainly by wind and honey bee. Aonla tree has two types of shoots, the indeterminate and determinate. Indeterminate shoots are longer and attain fresh growth in the season and do not bear flowers while determinate shoots come at the nodes of indeterminate shoots and number vary from 3-5 depending upon the genotype.
- 8. Determinate shootsbear very small reduced, closely arranged leaves giving the impression of pinnately compound leaves. Flowering takes place on determinate shoots appearing in spring season. There is no self incompatibility in Aonla and the cause of poor fruit set (12 - 18%) may be due to a high percentage of staminate flowers. Flower and fruit drop in Aonla is divided in three stages. i) The 'first drop' is the highest as 70% of the flowers drop off within three weeks of flowering due to unfertilized ovaries and degenerated ovules. ii) The 'second drop' occurs from June to September, consists of drop of young fruit lets at the time of dormancy break may be due to lack of pollination and fertilization. iii) The 'third drop' is spread over a period of rapid growth from August to October may be due to lack of auxin i.e. embryological and physiological factors.
- 9. CANOPY MANAGEMENT Canopyin a fruit tree refers to its physical composition comprising of the stem, branches, shoot and leaves. Canopy management is the ‘art’ of fruit growing - it is much more than cutting off a few branches. TRAINING AND PRUNING • Training is a practice in which tree growth is directed into a desired shape and form. • Training young fruit trees is essential for proper tree development. It is better to direct tree growth with training than to correct it with pruning. • Training includes summer training and summer pruning as well as dormant pruning.
- 10. The goalof tree training is to direct tree growth and minimize cutting. Pruning is the proper and judicious removal of plant parts such as shoots, spurs, leaves, roots or nipping away of terminal parts etc. to correct or maintain tree structure and increase its usefulness. It is done to – make the plant more productive and bear quality fruits, – increase longevity of the tree, – make it into manageable shape and – to get maximum returns from the orchard. Pruning is a dwarfing process and can be used to maintain any desired tree size. Removal of a branch removes not only stored carbohydrates but reduces the potential leaf surface as well. Pruning increases fruit size, nitrogen per growing point and stimulates growth near the cut.
- 11. Excessive pruningreduces fruitfulness especially with young vigorous trees that may already be developing too much vegetative growth. Large cuts results in excessive stimulation of sprouts near the cut, while well distributed small cuts spreads the stimulus better over the entire tree. The severity, kind and amount of pruning to be done on a tree depend on the – age, – existing framework, – condition of bark and wood, – Growth characteristics – Fruiting habit of the variety – Whether tree is permanent or filler Pruning is most often done during the winter, commonly referred to as dormant pruning. TRAINING Mainly concerned with giving a form or shape to the plant. Determines the general character and even details of the plant’s outline and of its branching and framework. Training includes summer training and summer pruning as well as dormant pruning. The goal of tree training is to direct tree growth and minimize cutting
- 12. PRUNNING Pruning isthe removal of a portion of a tree to correct or maintain tree structure. It has an effect on the function of the plant. It is meant to assist more in determining what the tree does in respect of fruiting. Pruning is most often done during the winter, commonly referred to as dormant pruning. Also done during summers, referred to as summer pruning. Objectives of Training To admit more sunlight and air to the centre of the tree and to expose maximum leaf surface to the sunlight. To direct the growth of the tree so that various cultural operations, such as spraying and harvesting are performed at the lowest cost. To protect the tree from sunburn and wind damage. To secure a balanced distribution of fruitbearing parts on the main limbs of the plant.
- 13. TRAINING AND PRUNINGIN AONLA As the branches of aonla trees often break off due to heavy crop load and brittle nature of the wood, aonla plant should be encouraged to form a shape of medium headed tree. The main branches should be allowed to appear at a height of 0.75 to 1.0 meter above the ground level. Plants should be trained to modified central leader system. Two to four branches with wide crotch angle, appearing in the opposite directions should be encouraged in early years. The unwanted branches need to be pinched off during March-April. In the subsequent years, 4-6 branches should be allowed to develop. Regular pruning of bearing aonla tree is not required as per growth habit, shedding of all determinate shoots (branchlets) encourages new growth in coming season. However, dead, broken, infested, overlapping or weak branches should be removed regularly. Removal of rootstock sprout is very important as per Growth habit ,shedding of all the determinate shoots encourages new growth in the coming season .
- 14. PRODUCTION CONSTRAINTS Aonlacrops has a seasonal as well as life long developmental pattern. In general, canopy of aonla has irregular shape. Trees of irregular shape and size are difficult to control and even result into poor fruit yield in the subsequent years as the lower branches of canopy gradually turns inert and infertile as well. In aonla, majority of the older plantations are of seedling origin and poor genetic potentiality which become senile. In several areas, plantations of improved varieties having good genetic potentiality have either gone unproductive or showing marked decline in productivity. This is the outcome of over crowded and intermingling of large branches and meager foliage, allowing poor light availability to growing shoots within the canopy. This renders them uneconomical. Such exhausted aonla trees can be rejuvenated by heading back of branches in winter for the production of new shoots, which can bear good crops in the years to come.
- 15. Points to beconsidered while adopting the rejuvenation technology 1.Plantation over commercial varieties where the canopy become over crowded resulting in reduction in yield can be rejuvenated followed by canopy management. 2. Older plantations of seedling origin which have become senile can be adopted for top worked by grafting (budding) with scion of superior varieties to upgrade seedling plantation with superior commercial varieties.
- 16. TECHNOLOGY FOR REJUVENATINGSENILE ORCHARDS There is a tendency of over lapping of canopy between 10 and 12 years of age depending on the nature of variety unless the canopy is maintained by trimming and thinning. Plantations which have more overlapping branches lead to dead wood development decline in yield in later years. Such plantation can be rejuvenated through canopy redevelopment. This is possible by hedging of branches followed by shoot management to modify the tree structure and maintain canopy size. Old and crowded aonla orchard
- 17. The rejuvenationtechnology involves heading back (topping) of branches during December –January at a height of 2.5 to 3.0 m from the ground level depending on the structure of individual trees in the orchard. Before rejuvenation pruning, branches are marked with white chalk by making a ring around the branches. The selected branches should initially be cut from the under side on the lower side by giving at least 10 cm deep cut. Thereafter, the cutting should be done from the upper surface of the branch. The cut portion of the branches is then pasted with cow dung or copper oxychloride to avoid infection of fungal diseases. Immediately after heading back, the pruned wood needs to be removed from the orchard so as to prevent the damage by trunk borers.
- 18. Heading back ofbranches Beheaded branches showing emergence Tree growth after 5 months of heading back Headed back trees with plastic mulch
- 19. MANIPULATION OF VEGETATIVEGROWTH The new shoots arise on pruned branches of heading back and 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. In this technique, only 4 to 6 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. During May-june selected branches are further pruned out to about 50 per cent of its total length for emergence of multiple shoots below the pruning points. This was mainly done to modify the tree structure and maintain canopy size. Fruiting starts on third year after rejuvenation. Yield levels during initial year are slightly low, while the yield from third year onward is better than the unpruned trees. Pruning Shoot (50%) of its total length Tree canopy after shoot thinning
- 20. REJUVENATION BY TOPWORKING Top working can be easily adopted in rejuvenated trees to upgrade the old and senile plantations of seedling progeny with superior commercial cultivars. Top working involves two steps (i) beheading of the tree to be top worked and (ii) budding with a elite material on the new flushes emerging out on the stumps of beheaded tree. The plants are headed back of 2.5 to 3.0 m above the ground level. Four to six shoots from the outer directions on main limbs should be allowed to develop. During june-july scion of desired varieties are grafted or budded on these shoots . After bud sprouting, the top portion of the shoot is removed. Numerous side shoots, which emerge on the pruned branches after the budding operation should be removed regularly as and when they emerge, so that tree of pure commercial variety is obtained.
- 21. Process of buddingtechnique on beheaded Trees
- 22. Since aonlais self incompatible, i.e. the pollens of same tree/variety can not fertilize its own ovary, the production from mono-culture orchards without appropriate polliniser varieties, suffers adversely as a result of problem of fruit set. Now pollinizer varieties are budded on developing shoots of pruned trees to strengthen pollination process and enhancement of fruit set and productivity. Budding with mixed varieties results in better yield. The best combination is NA-6 with NA-7; NA-7 with NA-10 and Kanchan with Krishna. Adequate care should be taken to manage the insectpest problems as these plants are prone to insect and some times wind damage
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- 24. Fruiting on rejuevenatedaonla tree Better canopy after rejuvenation by top working
- 26. INTERCROPPING IN REJUVENATEDORCHARD During initial 2-3 years after rejuvenation, there is a good opportunity for utilizing vacant interspaces in the orchard. Vegetables like bottlegourd ,okra,cauliflower,cucumber ,EFY ,marigold have been found well suited for intercropping in rejuvenated aonla orchards Elephant foot yam as intercrop in the rejuvenated orchards
- 27. NUTRIENT MANAGEMENT Thenutritional requirement in rejuvenated aonla trees largely depends on soil fertility and production. During the phase of heading back, 50 kg FYM along with 8 kg neem cake / plant is made. Six months after heading back manures and fertilizers may be given as 50 kg FYM + 4 kg neem cake + 1000 g Nitrogen + 500 g of potash and 750 gm of phosphorus /year. 50% of Nitrogen and entire dose of potash and phosphorus applied in January-February and rest dose of nitrogen is applied in June. Fertilizers are applied in a ring which covers 50 cm away from the trunk and covering the periphery . Soil should be dug to the depth of 8-10 cm and fertilizer should be properly mixed with the soil. Light irrigation is done immediately after the application of fertilizers. In sodic land, 100 g each of borax, zinc sulphate and copper sulphate should be applied along with fertilizers as per tree age and vigour. It is helpful in reducing fruit drop and improving fruit quality.
- 28. IRRIGATION Aonla, beinga hardy tree requires less irrigation.During winter and rainy seasons no irrigation is required but is required at an interval of 10-15 days during dry summer (April-June). In headed back trees, irrigation is done just after rejuvenation. Adequate watering is required for the optimum development of shoots in rejuvenated trees. If trees are not watered properly, there is always a feasibility that shoots do not grow to their appropriate level. It is, therefore, suggested to water those trees which are amputated for rejuvenation of old and senile orchards.
- 29. HARVESTING Changes incolour of fruit from creamy-white to brown is an indication of fruit maturity. Generally fully developed fruits are harvested. A budded/grafted aonla tree starts bearing third year onward after planting, whereas a seedling tree may take 6-8 years. Vegetatively propagated plants attain full bearing within 10-12 years.
- 30. REFERANCES Hand bookof Horticulture-K.L Chaddha Fruit crops –T.Radha and Dr.K.L Chadha Class notes Research papers Internet
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