The first few years in the life of a litchi tree are very important. One should make

Transcription

1 CHAPTER 7 CARE OF THE YOUNG ORCHARD The first few years in the ife of a itchi tree are very important. One shoud make every effort to get the young trees estabished quicky and to have them make good growth. For this reason, it is wise to foow a system of intense care for first 4-5 years of panting. Litchi sapings panted in June-Juy take fu advantage of monsoon season for their estabishment and initia growth. Up to October, pant grows we except the attack of some pests and put forth one or two new extension fush. Litchi pants are supposed to bear fruits after 5-6 years of panting. By this time, pants attain a definite framework and become physioogicay ready to bear fruits. Therefore, tree management system of deveoping pants shoud be foowed unti the management system is switched over to that for bearing trees. In the first two years, pants need some specia care for better growth and estabishment. Young orchards in particuar, suffer readiy from poor management and hence deay in bearing of commercia crops. Od trees, though more toerant, because of their greater reserve of food materias, wi nevertheess, respond positivey to cutura management. Moreover, it is not necessary and often not desirabe to foow a singe system to manage the orchard throughout its ife. An orchard is handed in one way when the trees are young and in different way when the trees become mature. Foowing care is taken initiay in estabishing itchi orchard to avoid future probems. The most common fauts observed in estabishing the newy panted tree are improper irrigation and ack of weed contro. These two fauts cause more stunting and oss of trees than any others during the first two years. Irrigation during the first year shoud be appied often (at east every 2 to 3 weeks), but each irrigation shoud be of short duration. Whie the root system is sti very sma, it may depete the moisture immediatey surrounding each root, and even though good moisture is found at the surface cose to the tree, the soi around the roots may be dry. Thus, frequent irrigations at short duration wi repenish the dry areas around the roots without water ogging the soi. Inexperienced growers often appy too much water at one time and drown the roots (that is, the excess water creates an oxygen deficiency), or they et them become too dry or they commit both errors.

2 THE 68 A Manua for Litchi Production PRODUCTION Weed growth around a young tree robs it of soi moisture, nutrients, and sunight, a of which are needed by the tree for the rapid growth so essentia to eary fowering and cropping. Weeds can be kept out by tiage or by surface muches of sawdust, bark chips, or back pastic. In the second and succeeding years, chemica herbicides can be appied to prevent weed growth. It is usuay hazardous to use chemica weed contro in the first season because of possibe injury to un-estabished trees. Pruning for Training The term training is defined as the cutting away of portions of a tree to obtain the desired shape and frame-work. At panting time, the tree is cut back to 0.70 to 0.80 meter if it is an unbranched ta saping. If it is a branched tree, it is reduced to three or four wide-anged branches, each of which is cut back to one-third its ength or to a desired ength to give it a proper baanced shape. It is important that the newy panted saping be pruned back enough so that the top is in good baance with the root system, which was pruned during the digging operation in the nursery. In genera, the permanent conventionay spaced orchard tree is deveoped so that three or four wide-anged side branches form the framework of the tree, with the uppermost branch becoming the modified eader (Fig. 7.1). However, trees to be spaced cosey in a hedgerow or those that are temporary fiers need a different sort of initia training. Hedgerow trees shoud be pruned and trained to restrict their growth within the specified spacing. New Evidence on Growth New evidence indicates that not a buds or branches of a itchi tree respond in the same way to imposed or natura inhibitory or stimuatory mechanisms. Some buds remain inactive whie some grow into vigorous shoots. The growth potentia of a bud (seen in its stored nutrients, water suppy, minera nutrients, and growth hormones) interacts with various inhibitory conditions to produce a net growth that refects the baance of opposing forces. There are severa growth patterns that are incompetey understood, but they are beieved to be directed by the interpay of hormones, gravity, ight, and initia pant vigor. The infuence on branch ange is independent of orientation with respect to gravity. As the bud begins to grow, the crotch ange between the young branch and the main axis enarges rapidy whie the branch tissue is not yet ignified. Later, this process of ange enargement ceases, indicating the reative rigidity of the system after secondary ce was are formed. Morphactins present in the pant tissues tend to ater a pant s norma responses to gravity and ight. Normay, pant roots grow downward toward the earth s center of gravity (positive geotropism), and shoots grow upward away from it (negative geotropism) as we as toward a source of ight (positive phototropism). Branch anges are infuenced by the mechanica pressure exerted on the branch base by tissues growing in the crotch area.

3 Care of the Young Orchard 69 Fig. 7.1: Frame work deveopment in itchi Care of the Young Orchard After the orchard is estabished, trees are trained to give them a desired shape. Initiay, ony minima corrective pruning shoud be done. During this period of deveoping the bearing surface, the east pruning is the best. Severe pruning may ead to adverse effect and potentia bearing surface is reduced and the time of first fowering may be deayed. Temporary fier trees that wi remain in the orchard ony 6-7 years shoud not be trained. Eary-bearing species/cutivars shoud be used as fiers, but even so, every practice shoud be directed toward maximum yied during the years prior to remova. Do not Negect Pant Basins Proper aeration near root zone and good sanitary conditions in the basins of newy panted itchi saping is a must for keeping the pants heathy and disease free. Proper growth of young pants can be ensured by timey hoeing and weeding of the basin which is considered to be the essentia and shoud aways receive first priority. If intercropping is being practiced, the itchi pants shoud not be kept in negected condition during pre-bearing stage. After harvest of

4 THE 70 A Manua for Litchi Production PRODUCTION every intercrops, the pant basins shoud be propery cutivated and essentia nutrients shoud be appied. It shoud aso be seen that the pest and diseases of intercrop are not causing damage to itchi pants. Any such negect of young orchards proves costy as fruiting is deayed and ongevity and productivity of the pants are reduced. Protecting Pants from Cod Newy panted itchi sapings face first winter from November February under North Indian conditions. For the successfu estabishment and growth during winter, it is necessary to protect the newy panted saping from cod. In North India, sometimes, winter becomes more severe eading to occurrence of frost. The frost damages the young eaves and growing tips and finay the pant may die. Therefore, the protection of itchi sapings for at east one winter or in some cases two seasons is very essentia. It is advisabe to estabish itchi orchards in such a manner that the rows run diagonay to the prevaiing wind direction to avoid creating a tunne effect. Before panting of itchi orchard, it is essentia to reserve some pace for panting of wind breaks at the border sides of orchard from which hot and high winds and frost are expected. To protect the pants from frost, thatching of individua pant is essentia. They can be thatched with any type of dried grass or dried stak of maize or bajra aong with paddy straw. The pant is covered from 3 sides eaving a gap towards east to aow entrance of sunight and air. For protection against frosts, the young itchi pants shoud be covered propery we in time and the thatching shoud be removed ony when the danger is over. Some growers remove the covers too eary, with the first warming up of temperatures after winter; but the trees are ikey to suffer if ate frosts occur. Basin irrigation, muching raising border crop and spray of water before anticipated frost date may be hepfu in reducing the extent of oss. Occurrence of haistorms is a natura phenomenon which causes partia or tota oss of itchi crop. Likewise, it must be protected in summer to avoid scorching from hot winds (Loo) and intense heat of the summer months. It is necessary to provide support to the pant by staking in the areas where high winds are more prevaent. The staking is hepfu to keep pant stem straight and save the pant from damage. When itchi have grown taer, the stem may be white washed with ime to protect from sunscad. Water Management Young itchi pants must be frequenty irrigated during the drought spe in rainy season, winter and summer months for at east one year. When the pants are we estabished in the fied, irrigation may be given as per need preferaby on the basis of soi moisture status. During vegetative growth period, every effort shoud be made to maintain sufficient moisture near root zone of the pant. Generay, irrigation at weeky interva during summer and fortnighty interva in winter aong with muching shoud be done in the first two years of pant estabishment. However, the quantity and frequency may be modified depending on

5 Care of the Young Orchard 71 the soi type, cimatic condition and method of raising orchard. Lighter sois wi have to be irrigated more frequenty than the cay sois. Irrigation frequency may be adjusted according to rainfa and evapo-transpiration during each season. During rainy season, water shoud not be aowed to stagnate around the pant as it wi affect the root activity adversey. Drainage may be provided near root zone by making sope at ower side. In marginay water ogged area, panting of itchi at raised patform can aso be done. Fertiizer Appication The itchi pant needs more nitrogen at young stage to promote pant growth, therefore during the estabishment and growth phase, higher proportion of nitrogenous fertiizer shoud be given than phosphatic and potassic fertiizers. As the pant grows, the requirement of fertiizer increases and therefore, the doses shoud be increased annuay unti the pant attains fu growth. For efficient use of appied fertiizer, it is aways better to spit the annua quantity of fertiizers in 2-3 parts and appy in the pant basin. The oss of fertiizer can further be minimized by avoiding its appication in the peak rainy season. As a matter of fact, fertiizer in young itchi pants shoud be appied during October and March whereas the manures shoud be appied during pre monsoon period (June-Juy). Fertiizers shoud be paced in a band spread in circe approximatey 30 cm away from the base of the pants and shoud be incorporated to the soi mechanicay without disturbing the roots. The distance of band shoud increase as the pant grows. Sufficient soi moisture is necessary after appication of the fertiizer mixture. Soi incorporation is not necessary if under tree sprinkers are used for irrigation of trees as fertiizers can be effectivey incorporated by irrigation water. Intercropping Intercropping is growing of two or more crops simutaneousy on the same piece of and. Since itchi trees require a considerabe ong juvenie phase to compete their canopy structure to bear fruits, there is sufficient scope to grow intercrops during initia years of estabishment. Usuay, the period of juveniity extends from 4 to 6 years but in some cases it may extend even more rendering the orchard unproductive during this period. So growing short duration crops is the ony answer to make the orchards productive in eary years of estabishment (Fig. 7.2). If three or four intercrops are grown in succession, it heps in receiving income from the orchards round the year. Intercropping aso heps in proper upkeep of the orchard as the orchard foor is frequenty hoed and weeded for raising intercrops. For those orchards which are near the cities or towns, it is aways better to grow vegetabes as intercrops as it is more paying. For distant orchards crops which can be stored onger ike onion, potato, turmeric and ginger can be grown. Ony those crops are seected which are adapted we to the cimatic and soi conditions of the area. Legumes are better choice for sois which are poor in nitrogen content. For young orchards, vegetabes which require abundant sunight can be seected. For oder orchards, shade-oving crops are preferred. It shoud be

6 THE 72 A Manua for Litchi Production PRODUCTION Fig. 7.2: Intercropping in young itchi orchard with gadious and amorphophaus kept in mind that the intercrop shoud not affect the management of the main crop or interfere with its cutura practices. It is not desirabe ordinariy to grow crops ike maize, sunfower or other exhaustive crops ike sugarcane, because of the exhaustion of nitrates and moisture. Intercrop shoud be compatibe with the main crop. Traiing vegetabes or vine crops are not desired as intercrops in itchi orchards. Growth habit shoud be such that it does not affect the deveopment of itchi crop directy. Certain pest and disease probems may be enhanced by growing two or more crops together. It is aso noted that intercrops appear to favour some pests and pathogens since they may act as aternative hosts. Such crops are not aowed to be grown together. Whie the orchard is young and non-bearing, the trees wi not need a the ground. A itchi orchard panted at a spacing of 10 m x 10 m in one hectare area provides as much as 0.8 ha open sunny space for intercropping in the first year of estabishment. Graduay, the avaiabe space decreases with the increase in size of the itchi trees and at the age of 10 years when canopy deveopment is compete, the entire ground surface is shaded. At this stage, it is generay advised to discontinue the practice of intercropping but this is not a rationa approach since the space beneath the canopy is not totay dark. So shade oving crops ike ginger, turmeric, bete vine and yams can be grown. There are appreciabe changes in the spectra composition of radiation with the nature of the canopy as shading created by trees is extremey variabe. As regards spectra composition, eaf canopies preferentiay absorb, and therefore, fiter out the visibe wave engths used in photosynthesis. Thus, shade ight has a ower portion of usefu wave engths and a greater portion of infrared, the ater being the wave engths argey responsibe for raising the temperature. Because of the diverse conditions under which itchi trees are grown, they can be interpanted with a arge number of other economic species. Fied crops ike peanut, potato, gram, pea, mung, sweet potato, yam and vegetabe crops ike cauifower, cabbage, spinach, okra, beet-root, kno-kho, carrot, chiies, radish, onion, cowpeas, coocasia can be

7 Care of the Young Orchard 73 grown successfuy in the orchards. Short duration fruit pants ike pineappe, papaya, banana, strawberry, cape-gooseberry, phasa, ime and emon can aso be grown as intercrops (Fig. 7.2). It is generay beieved that growing intercrops wi adversey affect the ong term productivity of the main crop. But pubished iterature show that the crux of the probem is the eve of management. When both the main crop and the intercrop are adequatey manured and managed we, intercropping is most often a paying exercise. This has been shown in severa experiments. On the other hand, if the additiona crop is aowed to be a parasite, the yieds of both components of the mixture wi be adversey affected. It is true that productivity of crop mixtures mainy depends on pant interactions. Intercrop and main crop draw their nourishment from the same environmenta resource poo. If seection of crop is not propery done then the extent of competition may be too high and can harm the productivity significanty. If seection is done carefuy taking care of aeria growth and root distribution pattern, then considerabe additiona benefits can be achieved by intercropping. Hence, the intercrops must have synergistic rather antagnostic effect on itchi pants. Muching Muching the itchi trees is an important and very usefu practice. Muches are effective in conserving soi moisture, maintaining root zone temperature, controing weed and soi erosion. Most of the organic materias incuding farm waste and other bi-products can be used as muching materia but hard to decay materias with high C:N ratio are better. Materias ike rice straw, rice husk, dried weeds, saw dust etc. can be used for muching purpose. When muches are used, care shoud be taken to inspect trees reguary for any termite activity to take appropriate contro measures. Termite activity may be increased with much appication. Canopy Architecture Providing a better frame is the first step to make pant prepared for heavy yieds expected under good management. Amost one year after panting, when pants are estabished, every care shoud be taken to maximize the pant growth so that the pant can be pruned and trained to provide good framework with we spaced spreading branches and open center canopy. For a proper framework, do not aow branches at the base of the main stem. Such branches shoud be removed/pinched off in the eary stages of growth to eave a standard main trunk without any branch up to a height of cm. Between this height, if 3-4 side branches are there, aow them to grow as imb but if branches are not there force the pant to produce by heading back or twisting the main trunk at approximate height and ensure 4 we spaced shoots in each direction. These wi deveop into imbs. After cm, each imb shoud have 2-3 primary branches. Each of these primary branches shoud cuminate into 2-3 secondary and further into 2-4 tertiary branches. To train branches as spreading imbs, staking of individua branch can be done to avoid breaking. This way, pants can be provided

8 THE 74 A Manua for Litchi Production PRODUCTION with better canopy architecture. The pruning and training process must be continued for 2-3 years because a these can not be done in a singe operation or two. Therefore, growers must reguary visit the pants and train them as and when necessary. Pruning shoud be commenced in we estabished pants before any anticipated major growth fush. Pant Protection During dry periods, termites may damage underground parts of the pant. To overcome this probem appy a band of engine oi on the base of the stem up to about 45 cm height. Simiary, the measures to contro the pests and diseases shoud be taken time and time to save the deveoping itchi pants. Deatied information on insect pest management has been given separatey. In the dry zone, heavy winds bow during May-June. Most cutivated ands are damaged by fire at this time of the year. To protect the itchi pantation by spreading fire, have a 5-10 m wide fire bet around the orchard pough and harrowed to remove dry grass. Aso during the dry months of the year, keep an area of about 3 m around the base of trees weed free. This might protect trees even if a fire spreads over the orchard. Bringing the Orchard into Bearing Proper care, training and pruning the young pant hep getting earier fower induction and fruiting. Very intense pruning may have adverse effect on eary yieds as potentia bearing surface is reduced and the time of first fowering is deayed. Under many cimatic conditions, young itchi trees fai to yied fruit as soon as tree size is sufficient to support a crop. Such trees are sow to initiate fowers, and when bossoming does occur, yied is ow because of poor set. Tests indicated that pruning reduced yied and girding increased it on young trees. Trunk or branch girding can be used to induce fowering and heavier cropping in some tree crops. Ringing (making a singe cut through the bark competey encircing the trunk) young itchi trees increased yied, atered tree shape, and reduced tree size. The ess vigorous, ringed trees responded we to the heavier pruning required to keep the trees confined to the provided spacing. The foowing points shoud be remembered regarding the care of young itchi trees to favor eary bearing. Don t prune after initia training. Ring fiers or other vigorous trees to induce eary fruiting. Add nitrogen and other fertiizers if trees ack vigour. Don t ring a weak tree. Ring eary (fu boom to peta fa) and use ony a singe cut (no bark remova).