High Density Planting in Fruit Crops

Advancing knowledge in litchi tree architecture, growth physiology, possibility of using
growth retardants has enabled farmers to adopt closer planting and maintaining
reachable canopy. This system is popularly known as the High Density Planting (HDP).
It enables profitable cropping, high regular yields and improved farm management practices,
leading to higher productivity. Today new orchards of litchis are being attempted to plant in
this system with a view to produce higher fruit yield and increased profitably. Use of growth
retardants which restricts tree growth and encourages early flower induction, have also been
found helpful for these high-density planting systems.
High density planting technique is a modern method of litchi cultivation involving
planting of litchi trees densely, allowing small or dwarf trees with modified canopy for better
light interception and distribution and ease of mechanised field operations. Control of pests
and diseases, weeds and pruning of tree canopy can be carried out by machine. Irrigation and
fertigation are automatically controlled. Such system produces precocious cropping, high and
regular yields of good quality fruits and low labour requirement to meet ever rising production
costs. Merit of HDP over Normal Planting
Increasing pressure on land owing to diversion of orchard lands to various other obvious
reasons as well as rising energy and land-costs, together with mounting demand for fruits have
made it imperative to achieve higher productivity of litchi from limited space. One should be
very conscious in case of high density litchi because closer spacing may bring negative impact
in growers’ fields if the complete package of high density has not been properly understood
and followed.
The normal planting distance in litchi has been 9-10 m. Such orchard takes 10-15 years
to provide economic returns depending upon the cultivar, and cultural practices. Due to poor
early returns and clash between the cultural requirements of the intercrop with main crop, litchi
orcharding so far is done by large farmers who can afford tall treesComponents of High Density Planting
There are four major components of high density planting system. These are:
1. Planting Density: Even though a small canopy with a high number of well-illuminated
leaves is efficient in photosynthesis but it is very poor in light interception, which leads
to low potential yield per hectare. Light interception could be improved by increasing
tree density. An optimum tree density is the level of density which is required to facilitate
optimum light distribution and interception leading to high photosynthesis. As a result,
yield per hectare is maximized. An optimum light interception is a factor of plant form,
planting density, tree arrangement and leaf response to light for photosynthesis. Optimum
light interception can be defined as a level of light intercepted by an orchard system
above or below which, the economic yield will be reduced.

1. High Density Planting and its importance in Fruit Crops Course : Advances in Fruit Science Amrinder Singh Ph.D. Scholar

2. High Density Planting (HDP ) Accommodating more number of plants per unit area as compare to normal planting Intensive form of fruit production; high relevance to the food and nutritional security Many fruit trees are now grafted on to size controlling clonal rootstocks and planted at much higher densities Total yield per unit area of land is several times more than low density planting as number of plants is more in HDP

3. Types of HDP Semi-intensive: 500-1000 trees/ha Intensive: 1000-10,000 trees/ha Super-intensive/Meadow orcharding: 20,000-1,00,000 trees/ha

4. Planting Densities Low HDP <250 trees/ha Moderate HDP 250 to 500 trees/ha High HDP 500 to 1250 trees/ha Ultra HDP >1250 trees/ha Super HDP 20,000 trees/ha Meadow Orchard >70,000 trees/ha

5. Advantages of High Density Planting Best Utilization of Land and Resources Higher yield per unit area High Economic Return Easy Harvest Improved Quality of Harvest Convenient Farm Mechanization

6. Use of dwarfing rootstock and scion cultivars Clonal rootstock Training system Pruning of plants Use of Growth retardants Light interception Planting density Canopy management Key aspects of High Density Planting

7. Dwarfing Rootstock Apple M27, M9, M26, M4, M7, MM106 Mango Vellaikolumbun, Olour Guava Pu s a srij an , P . fri e drichstha l ianu m , P . pumilum Ber Z. nummularia Citrus Alemow, Trifoliate orange, Flying dragon Pear Oregon 211, Oregon 249, Quince C Plum St. Julien, Pixy Dwarfing Scion Apple Red Spur, Starkrimson, Gold Spur, Well Spur, Oregon Spur, Silver Spur, Red Chief Mango Amrapalli Papaya Pusa Nanha Peach Red Heaven Sapota PKM 1 and PKM 1

8. Training and Pruning Training of plants is shaping or adapting them to specific forms so that they can function more efficiently and effectively Training includes tying, fastening, staking or supporting over a trellis or pergola in a certain fashion or some of its parts are removed to provide specific framework Pruning may be defined as the art and science of cutting away a portion of the plant to improve the shape Principles of Training and Pruning To influence its growth, to improve lumber, flowering and fruitfulness to improve the quality of the produce or to repair injury Modification of apical dominance Balance of root and shoot Alteration of growth phases Modification of environmental effects Objectives of Training and pruning To control the direction of growth To develop a strong framework To control the amount of growth To influence productiveness To improve quality of product To utilize space efficiently To increase the usefulness of the plant

9. Methods of Training Fruit Trees

10. Central Leader System The main stem of the tree is allowed to grow uninterrupted The first branch is allowed to grow at 45-50 cm height from the ground Distance between primary branches is 15 to 20 cm As the main stem grows continuously, the tree attain robust shape Less interception of light by lower branches, they remain unproductive The bearing is confined in the top portion of the trees This method is not suitable for high altitude and hot arid places where wind velocity is high

11. Open Centre System Beheaded when the plant attains the height of 40 to 50 cm 4 to 5 well scattered, arranged and well distributed branches all around the stem are selected They attains less height Better interception light by all the shoots and all the branches are capable of bearing flowers and shoots Facilitates easy carrying out of operations like harvesting and spraying on the tree In this system, the plant take a bowl shape which provides a good base for settling of frost Not suitable for high altitude where frost observance is common

12. Modified Leader System This is intermediate form of central leader and open centre system and draws the benefit of both the systems. The main leader is allowed to grow for few years until 6 to 8 scaffold branches develop around the central leader After that, it is headed back to a height of 120 to 130 cm from ground level The first shoot is selected at a height of 40 cm from the ground and 4-5 branches at a distance of 15-20 cm and placed around the main stem are selected. The plant attains a moderate height All retained branches receive ample light and there is better production on the tree This is very suitable and practiced almost in all regions Delayed Open Centre

13. Methods of Pruning Heading back Removal of terminal portion of shoot leaving basal portion intact Th i nning Sel e c t i ve a nd co m plete re m o v a l o f p a rt o f the plant Circular ring of bark measuring about 3 cm in length is removed Ringing or Girdling Making a notch below a bud by removing a wedge shaped piece of bark Nicking Making a notch above a bud by removing a wedge shaped piece of bark Notching

14. HIGH/ULTRA High DENSITY PLANTING IN MANGO

15. High Density Planting in Mango “Planting of more number of plants than optimum through manipulation of tree size” High density planting (HDP) (5x5m) or ultra-high density planting (UHDP) system (3x2m/4x2m) aims to make maximum use of land to achieve high yields in the early periods of orchard along with ease in its management. Is a technique which has utilized all the resources optimally and thus, increase the production per unit area as well as raises profit margin of mango farmers Imp** Adoption of High Density Planting (HDP) system with proper canopy management practices coupled with drip-fertigation system is highly essential to increase the productivity.

16. Why HDP/UHDP? India is the world’s largest producer and exporter of Mango but the average yield/ha in India is one of the lowest in the world-even behind countries like Bangladesh and Pakistan. Productivity: India (9.66 MT/ha) Brazil (16 MT/ha) India rank first among Mango producing countries in the world. The export of fresh mango fruit is limited only to Alphonso and Dashehari varieties, which accounts for 0.2 % of the total production. UHDP combined with other sustainable agricultural techniques, has the potential to yield 200% more produce than that of the traditional method.

17. Causes of Low Productivity of Mango in lndia 1. Old and Senile Orchards 2. Traditional Planting System 3. Rainfed and less intensive Farming System 4. No canopy management

18. Inefficient nutrient management Improper orchard management practices Greater losses due to insect, pests and diseases Natural phenomenon like heavy rainfall, strong wind velocity, hailstorm etc. Unscientific method applied by farmers for plucking the fruits and unaware about the quality parameters for export Mango. Other C auses

19. Double hedge row system of planting (10 x 5 x 5 m) is the best planting system for obtaining maximum number of fruits and the highest yield per unit area. (Jasmine et al. 2009). However, State Department has started recommending HDP with 5 x 5 m spacing for all commercial varieties. In South India, under tropical condition, the following spacings have been practiced (Table 1). Study of different planting system in Mango cv. Kalepad at TNAU

20. ULTRA HIGH DENSITY PLANTING SYSTEM Experiment conducted by TNAU in collaboration with Jain Irrigation Systems Ltd (JISL), Udumalpet Revealed that we can still go for closer spacing of 3 x 2 m UHDP (674 plants/acre) As the Cultivation Practices are very intensive, high value varieties are recommended. Pits of 1m 3 are dugged and allowed to wither for some weeks before filling with mixture of planting media. MEDIA 40-50 kg native soil, 0.5- 1.0 kg SSP 0.25 kg Neem cake 20 kg compost or 10 kg VC 10-15 g of Thimet/Furadon Plantations are raised by using grafted saplings. Graft joint should remain just above the ground level.

21. Canopy Management in Mango Canopy management is essential in HDP/UHDP system To control size of the tree. To strike a balance between vigour and productivity. It starts from early months from planting. Axil- The angle formed by a branch or leaf and the part of the plant from which it arises. Bud- An unexpanded flower or vegetative shoot. Crotch- The angle between two branches or shoots near the point of their union Heading back- Cutting away a portion of the terminal growth of a branch or shoot, usually to control the size of the tree or shrub. Pinch- Removing a growing shoot or bud by pinching it between the thumb and forefinger S caffol d - A branch ar i sing from the tr u n k . Thinning out- When a shoot is entirely removed from the point of its origin and no re-growth is allowed to occur from the cut ends. Trunk- The main woody stem of the tree Water sprout- A vigorous shoot rising from auxiliary buds on the trunk or older branches

22. When the plant height reaches 45-60 cm, the terminal bud should be pinched at 5-6 cm below the apex to encourage growth of auxiliary buds Ult i m a t ely t he tr e e row w i ll f orm a do m e shaped hedge Training After the growth from auxiliary buds 2-3 vigorous shoots are to be retained in different directions at 15-20cm interval which will develop as primary branches After 4-6 months growth of primary branches, they should be headed back at 45-60 cm length to allow further growth of 4-5 secondary shoots on each branch, which in turn will form tertiary shoots in due course In many orchards, improper training especially the formative pruning resulted in overcrowding of branches resulting in more incidences of hopper, powdery mildew and anthracnose disease etc. Canopy management in young mango trees

23. Pruning is very essential and critical operation of HDP or UHDP to maintain fruiting shoots and contain the canopy Pruning Pruning must be completed as soon as possible after harvest preferably before 15th June in Central and Southern India Tertiary branches have to be headed back in such a way that the plant height can be maintained at 1.5 m and having 10-15 tertiary shoots Cut ends to be pasted with Bordeaux paste or 2% Copper Oxychloride (COC) suspension About one month after pruning, thinning of newly emerged shoots is essential to avoid excess shoots and overcrowding On each tertiary shoots 3-4 new shoots are to be maintained

24. Important points to be borne while carrying out canopy management in young Mango trees I. Heading back 1.Age: 1 year 2.Time: Oct-Dec 3.Height: 40-60 cm from the ground 4.Emergence of new shoot: Spring season (March-April) For development of ideal open canopy Thinning of excessive shoots (May). R e tain 4 w e l l distr i b u t e d shoots in all directions (Primary branches) III. Crotch angle: 45 o Bend the shoot if crotch angle is small IV. 2nd cutting of 1 o branches Stag e : Ma t u r e shoot (green to brown-7 to 8 months). Time: Oct. to Nov. Induces new growth: Spring shoots per primary V . T h in n ing 1 . Retain 2-3 branch. 2 . Th e se shoots develop as secondary branches. T h is initial t raining results in o p en and spreading canopy of trees.

25. Canopy management in Bearing Mango Orchards Soil app. of PCB@1g a.i./m 2 tree canopy Limitation: It can be practiced only under irrigated and well maintained plantations.

26. Light pruning in one year followed by medium pruning in the next year should be followed in alternate years to maintain the tree size under control Fig: Ultra-high density planting systems results in higher productivity and maintenance of Mango trees

27. Important points to be borne while carrying out canopy management in bearing trees Identify uprightly growing branches and thin them out for increasing the productivity Remove only one or two uprightly growing branches from centre of tree to reduce tree height significantly and increase light interception for better photosynthesis Cutting of uprightly growing branches should be done during Oct-Dec from the base of their origin A void bark sp l i t t i ng b y gi v i n g smooth cut Protect branches with wide crotch angle as they are more productive In bearing mango trees, not >25 % biomass should be removed at a time for better c a n op y m an a gemen t ; o th e rwise it r esul t s in exces s ive vegetative growth Under UH D P system, Remove 10-15 % biomass annually during Oct-Dec Increase light penetration inside the canopy Removal includes criss cross branches, dead wood and diseased shoots

28. Nutrient and Water management The success of mango production under HDP or UHDP also depends upon proper nutrient and water management . Irrigation management Irrigation and fertilizer are provided through drip irrigation system. Table 3: Water requirement in different months 4

29. Bearing Trees (3 rd year onwards) Irrigation to be given at survival level during September 3 rd week October to to induce flowering. The general recommendation is that if rainfall exceeds 10 mm in any one day, suspend drip irrigation for the next 2 to 3 days. First 2 years: One dripper of 4L/hr/tree. 3 rd years onwards : Two drippers of 4L/hr/tree. When 2 drippers are installed they should be placed 45 cm away from the trunk W A T E R

30. Application of fertilizer Timing and number of schedule may vary with place to place depending upon the flowering and fruiting season including the variety under cultivation.

31. Jain Irrigation Systems Limited recommends the following fertigation schedule for UHDP mangoes (Soman 2009)

32. 3x2m/4x2m Comparison between UHDP, HDP and Conventional Method of Planting

33. High Density Planting in Apple

34. Commonly used Rootstocks for HDP Dwarfing/Semi-dwarfing M9, M26, M4, M7 and MM106 Meadow orchards M27 Spur types MM106 and MM109 for and M7 Non-spur types MM111 For J&K MM106

35. Training System followed in Apple for HDP Ever since the introduction of dwarfing rootstocks, some efforts to standardize the training system of dwarf trees have been made. In the late fifties, when clonal Malling rootstocks were introduced in India, some experimental dwarf plantations were raised as spindle bush, dwarf pyramids and cordons. Spindle bush raised on M9, M7 and M4 rootstocks are found to be the most suitable in the agroclimatic conditions of Himachal Pradesh Palmette is suitable on sloppy lands with narrow terraces Spind l e Bush Dwarf Pyramid Espal i er C o rdon Palmette

36. Spindle Bush It is a small, conical, central leader tree of only 2m height and maximum diameter of 1.5m. Horizontal fruiting laterals are trained from about 0.4m above the ground With little pruning and horizontal bending of laterals , these spindles start early cropping Dwarfing rootstock: M9 Semi dwarfing rootstock: M7 or MM106 with spur type cultivars

37. Steps in the development of Spindle Bush System At the time of planting the, whip is cut back to about 0.75 to 1 m height from the ground In summer, a no. of laterals develop around the trunk, 3 to 4 primary branches are selected with strong crotch angle Those having angle <45 o are tied down with strings to hold them in horizontal position The bottom 45 to 60 cm are left without any shoots In t his for m , the se l ec t e d br a nc h e s a re much more closely spaced (10 cm) The central leader is headed severely headed back while the side shoots are left unpruned When 15 to 20 primary branches are obtained, the central leader is headed back (30 to 40 cm from the top most branch) Subsequent winter pruning should be followed Note: No secondary branches are encouraged

38. Dwarf Pyramid It is low headed, compact, central leader tree The lowest branches arises at a distance of 30 to 35 cm from the ground It has 20 to 30 primary branches well distributed in all direction around the main stem The central leader is retained throughout the life The successive branches radiating at intervals along the main leader, gradually diminishing in length from bottom to top, giving the tree a pyramidal shape The height of the tree is generally kept about 2m and the spread between 1 to 2 m Spacing: 3-4 x 2-3 m M9 M2 M4 M7 M M 106 M M 104 Starts early production from 3 rd to 4 th year after pla n ting

39. Steps in the development of Dwarf Pyramid The whip are cut back to about 50 cm a planting First Winter Laterals are cut back to 15-20 cm of the previous season’s growth The central leader is cut back to about 20-25 cm of the previous season’s growth During growing point, when shoot most of the shoots are of pencil size, firm and resistant to bending, summer pruning is done Immature shoots are left untouched Mature shoots are cut back to 5 to 6 leaves The central leader is also left untouched Later in summer season, the immature shoots are left unpruned Second Winter Any secondary growth resulted from summer pruning is cut back to a single good bud The central leader is headed back to 20-25 cm of new growth

40. The central leader is not allowed to reach >2m height. Any blossom arising on the central leader during the early years are removed to avoid bending of central leader under the weight of fruit In an ideal pyramid, the lowest branches should attain a length of 1m, the middle branch- 60 to 75 cm and the upper branches- 45 cm con t…… . Dwarf Pyramid Tree (4 years from planting)

41. Espalier system of training It refers to support used for training trees It consist of 3 to 6 tiers of horizontal branches are trained to grow 1 ft apart from one another at right angles to the main stem Using poles, 3 to 6 rows of wires are stretched one above the other First row of wire at the height of 6o to 70 cm, second row 130 to 140 cm and third row 200 cm from ground level. Over these wires, the branches are trained in both the directions, parallel to the ground

42. V ertical A x is in Apple 500 1000 trees/acre ‐ Dwarfing rootstocks Narrow pyramid shape with dominant central leader Max height of about 10 ft Few cuts made during the first few years after planting V ertical A x is: Planting Y ear Ideal tree has 4 branches evenly spaced and central leader Remove any branches within 18” of soil surface Remove branches that are at a narrow angle or unevenly spaced around the leader The leader should also be tied to the post at this time

43. In early July, any branches that are at less than a 60-degree angle from the central leader should be spread or tied down to this angle. Wire or plastic tree spreaders and other products are available commercially. When using cement weights, the branch initially should be weighted at slightly less than a 60-degree angle, since the branch angle will increase with time. Upright sprouts that were not spread during July should be removed later in the growing season or during dormancy. Tree weights can be removed from limbs any time after late August. Fig: (A) Limbs are spread in early July of the first growing season to a 60-degree angle from trunk. (B) Clothespins attached to weights can be used to spread limbs

44. V ertical A x is: 2 n d Y ear In early spring of the second growing season, remove vigorous shoots that compete with the central leader V ert i cal A x i s : 3rd Y ear In the dormant season after the third year, prune the lower branches of adjacent trees that have grown together. Maintaining Mature Tree To limit the height of the tree, the central leader can be bent over and tied to the post, or Cut back to a less vigorous lateral branch to form a new leader.

45. Meadow Orchard in Guava

46. CISH, Lucknow

47. Component for Meadow Orchard System Singh (2013) Dwarf Suitable to market Varieties Root stock Plant utilize maximum light Suitable to guava well fertile Near to source Water INM IPM True to type Healthy Free from disease & pest Plant trained for making dwarf canopy

48. Establishing Meadow Orchard Meadow Orchard System is a new concept of guava planting which has been developed for the first time in India at Central Institute for Subtropical Horticulture , Lucknow Planting The planting is done at 2.0 m (row to row) x 1.0 m (plant to plant), which gives a density of 5000 plants ha -1 .

49. First pruning The tree are pruned and tra i ned three ti m e i n a y ear t o a l low maximum production of quality fruit during the first year. A single trunk tree with no interfering branches up to 30-40 cm from the ground level is desirable to make dwarf tree architecture After a period of 1-2 month of planting all the tree are topped at a uniform height of 30-40 cm from the ground level initiation of new gr o wth be l ow the cut and no side shoot or branch s h ould remain after topping. This is done to make a single trunk straight up to 40 cm height.

50. First pruning Growth after first pruning Topping at height of 30 to 40 cm from the ground level

51. Second pruning After 15-20 days of topping new shoot emerge. In general, 3-4 shoot are retained from below the cut point after topping . As shoot mature generally after a period of 3-4 month, they are reduced by 50 percent of their total length so that new shoot emerge below the cut Point. This is done to attain the desirable tree canopy architecture and strong frame work.

52. Second pruning

53. Third pruning The emerged shoot are allow to grow for 3-4 month before they are again pruned by 50 per cent. After pruning, new shoot emerge on which flowering take place. It is emphasized that shoot pruning is done thrice a year. This leads to desired canopy development. Though fruiting starts in the same year. Pruning is continued so that plants remain dwarf. After a year, pruning operation is done especially in May-June, September- October and January-February.

54. Third pruning

55. Initiation of new shoot and flowering after shoot pruning Re-pruning of shoot (above the fruiting point) of shoot for initiation of new shoot New shoot emerge after re-pruning and flowering take place A B C

56. Pruned tree is heavily Fruiting

57. Steps involved in Meadow Orchard CISH, Lucknow

58. Continue shoot pruning (50%) on tree every year Field planting (2×1m) Top tree height of 30-40 cm from the ground level after 1-2 month of planting New shoot emerge below the cut surface Retain 3 to 4 shoot only Prune the shoot after 3-4 month of emergence (cutting back to 50% of their total length) Multiple shoot emerge below the cut end Further Prune the shoot after 3-4 month of emergence (cutting back to 50% of their total length) Shoot initiate and flowering take place Meadow Orcharding Singh (2008)

59. Singh (2008) con t .. . .

60. Back pruning 50 per cent removal of entire plant

61. Growth pattern and fruiting under meadow orchard 1 st year 2 nd year

62. Growth pattern and fruiting under meadow orchard 3 rd year 4 th ye a r

63. CISH, Lucknow

64. Maximum fruiting branches. Minimum structural branches. Better utilization of solar radiation. Increase the photosynthetic efficiency. Due to the dwarf tree minimum operation cost. More trees per unit area leading to higher income. Advantage of Meadow Orcharding

65. Attributes Traditional system Meadow system Bearing After two years From first year Production Average yield is 12-20 t ha -1 Average yield is 40-60 t ha -1 Management Difficult to manage due to large tree size Easy to manage due to small tree size Labour r equi r ement Requires more labour Requires less labour Production cost Higher cost of production Lower cost of production Quality Large canopy, poor sunlight penetration and poor quality fruits Small canopy better air and sunlight penetration ,minimum disease incidence and high quality fruit with good colour development . Comparison between traditional system and meadow orchard system of guava

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