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Cultivation of litchis

China litchi


Temperature and humidity

  • The average maximum temperature in the litchi-producing areas of South Africa should be at least 23 °C during October and 24 °C during November, with a relative humidity of 50 % and higher.
  • The average monthly minimum temperature in areas where litchis are produced should be above 6 °C. Areas where heavy frost occurs are not suitable for litchi production. It should, however, be cold and dry enough in winter to ensure good dormancy.
  • The minimum temperature in some Lowveld areas (Malelane and Komatipoort) does not drop low enough in winter to give the trees the proper dormancy period. Trees can be forced into dormancy by withholding water/irrigation during the 3 coldest months of the year. Producers must, however, ensure that especially young trees do not dry out.
    China litchi

Soil

  • Litchis grow very well, especially in sandy soil in the cooler subtropical areas.
  • However, the trees also grow and produce well in clay soil in warmer areas.
  • Litchis are well adapted to different soil types.

Water supply

  • Because of the varying root distribution in different soils (deep in sandy soils, shallow in clay soils) water is very important for the optimum development of the plant.
  • In sandy soils short irrigation cycles with small quantities of water are usually effective.
  • In clay soils water is available for longer periods, but it is important that the soil does not become too wet or too dry.

Drainage

  • Poorly-drained soil or soil with impenetrable layers shallower than 1 m below the surface is not suitable for litchis.
  • Although gravelly or rocky soils drain well, these do not supply enough water to the trees because of poor waterholding capacity. Good irrigation practices, such as wetting the soil more frequently with small quantities of water will make these soils more suitable.

Cultivars

Litchis were originally imported from China, India, Taiwan and Florida, USA. Cultivars grown in South Africa are divided into the following groups:

Mauritius group

This group is usually planted locally as well as abroad and produces satisfactory yields and fruit of good quality, e.g. H.L.H., Mauritius, Muzaffarpur, Late Large Red, Hazipur, Saharanpur and Rose-Scented.

Chinese group

These trees produce very poor yields, but the fruit is of excellent quality and has a high percentage of chicken-tongue seeds. Cultivars include Haak Yip, Shang Shou Huai, Kontand, Glutinous Rice and Three Months Red.

Madras group

These trees bear colourful red fruit, but fruit quality is poor. Cultivars include Kafri, Shorts Seedless, Johnstone's Favourite, Emmerson, Durbhanga, Maries, Mooragusha, Madras 19, Hazipur/Saharanpur, Red McLean, Brewster and Bedana.

Tree quality

  • A good air-layer tree has a single erect stem. The first scaffold branches should branch horizontally at a height of about 200 mm. Any acute forks that branch lower than 200 mm should be avoided.
  • In grafted trees the graft-union height should be about 200 mm from the ground so that the first scaffold branches can branch at 300 mm. The graft union must be strongly attached and nurserymen must remove the grafting strip so that girdling cannot occur.

Aftercare of grafted trees

Trees can also be propagated by means of grafting.

  • Weekly aftercare is very important and suckers and wild shoots that develop on the rootstock below the graft wound must be removed.
  • After 5 to 6 weeks the buds start swelling and growing. A small cut can then be made through the plastic next to the bud. The bud grows through this cut, but the plastic strip must not be removed too soon. Once the first new growth has hardened off, the strip can be removed.
  • Grafted trees have a better root system than trees developed from air layers and therefore show rapid initial growth. Air layering is, however, preferred to grafting because of a better end product.

Soil sampling

A representative soil sample should be taken for analysis. A soil sample must represent a homogeneous area where there are no visible soil differences. If there are colour or texture differences the land should be subdivided and separate samples of the different parts should be taken. Use a spade to take the samples.

How deep?

  • Take soil samples up to 300 mm below the soil surface.
  • Take subsoil samples from 300 to 500 mm below the soil surface.

How many?

  • A sample should consist of not less than 10 subsamples.
  • The area represented by the sample should not exceed 3 ha.

Where?

The samples must be taken evenly over the entire area.

Mixing and packing

  • Mix the subsamples of a particular land thoroughly in a clean container (not a fertiliser bag). Keep the topsoil (0-300 mm) separate from the subsoil (300-500 mm).
  • A 2-kg sample of this mixture is then packed into clean plastic bags or suitable containers. Use separate containers for the top and subsoil.
  • Put a label on the outside of the container to prevent it from becoming illegible. On the label must appear:

        - Your name

        - The number of the land

        - The depth at which the sample was taken.

Results

The results will provide valuable information on the type and quantity of fertilisation that should be applied before planting. Remember to incorporate the required quantity of lime about 6 to 12 months before planting if a large quantity is required and phosphate about 3 months before planting.

Soil preparation

  • Examine the soil for suitability in respect of depth, drainage and compacted layers. It should preferably be 1 to 2 m deep.
  • Prepare the soil according to the results of the soil analysis, especially when large quantities of lime are required.
  • If the soil is suitable for litchi production, it must be prepared well in advance.
  • Before planting, the soil must be tilled as deep and as thoroughly as possible so that it will not be necessary to make the planting holes too big.
  • If the soil is very acid, heavy lime applications may be necessary. Two-thirds of the recommended quantity of lime must be scattered over the planting area, mixed with the topsoil and then ploughed in as deep as possible, at least 9 to 12 months before planting. Calcium (lime) moves very slowly downwards into the soil and must therefore be worked in to the depth of the root zone.
  • A cover crop can then be planted and ploughed in about 6 months later to improve the organic matter content of the soil. The remaining lime (one third) and all the required phosphate must be scattered and incorporated at the same time. The trees can be planted 3 months later.
  • If a lighter lime application (2_4 t/ha) is required, the lime can be worked into the soil at least 3 months before planting and phosphate 1 month before planting.

Planting

Remember that litchi trees have a long life and become large.

  • Trees should be planted far apart to eliminate competition and to prevent branches of adjoining trees from growing into each other.
  • The entire outer area of the tree must be exposed to sunlight and air movement.

Planting distance

A 25-year-old tree can reach a crown diameter of 12 m. If trees are widely spaced and later become uncontrollably big an economic yield will not be possible. If the trees are to be spaced closely together, size must be controlled from the start by pruning. Try to plant as many controllable trees as possible per hectare. The ideal planting distance is 9 x 6 m.

Planting the trees

  • Litchi trees can be transplanted any time of the year, but the best time is during spring or at the beginning of the rainy season.
  • Planting holes should be square (in deep-ploughed soil 300 x 500 mm and in nonploughed soil 500 x 500 mm).
  • Mix the topsoil with compost and put it back into the bottom of the hole.
  • When planting the tree, remove the container and loosen the soil around the roots without damaging the roots.
  • After planting, compress the soil slightly by standing on it.
  • Wet the soil around the tree immediately after planting.
  • Place a mulch around the newly-transplanted tree.
  • Irrigate young trees regularly after planting. They must never suffer from a water shortage or too wet conditions.

Leaf analysis

Leaf analysis is the only technique according to which sensible fertilisation can be applied to a specific planting. The following aspects are important:

  • The correct time for sampling is from mid-September to mid-November.
  • The correct leaf must be sampled (see figure).
  • The first leaf sample of a specific planting must be accompanied by a soil sample. 
    A leaf and soil sample must represent a planting of not more than 3 ha.
  • The sampling method is important:

- Select about 20 healthy trees, well distributed throughout the planting.

- The trees must be of homogeneous appearance and representative of the average trees in the planting.

- Sample 4 leaves per tree.

- Do not take samples from obviously good or weak trees.

China litchi
Sample either of the 2 leaves coloured in the illustration

Fertilisation

Do not fertilise newly-transplanted trees too soon. Fertiliser should only be applied about 1 year after transplanting. The applications must be very light and broadcast evenly, but not against the stems of the trees. Irrigate after applying fertiliser.

Application and quantities

  • Fertiliser should be broadcast evenly about 0,2 m from the stem to 0,5 m outside the drip area of the tree.
  • Irrigate lightly immediately after application. Fertilisers must not be worked into the soil.
  • As soon as the trees are established and start growing, fertiliser must be applied regularly according to the quantities given in the table.

Time of application

Quantity of fertiliser per tree per year according to age (g)

Age years

 LAN 28 % N Superphosphate

  Potassium
chloride

1

2 - 3

4 - 5

6 - 7

8 - 9

10 - 11

12 - 13

14 - 15

15 and older

200

500

1 000

1 500

2 000

2 500

3 000

3 500 

4 000

250

250 

250

500

500

750

750 

1 000

1 000

50

100

200

300

400

500

750

1 000

1 000

 

Remember:

This is only a guideline; correct fertilisation can only be applied according to the soil analysis for young trees and soil and leaf analyses for fruit-bearing trees.

Nitrogen (N)

First year

- divide the nitrogen fertiliser into 8 equal monthly applications of 25 g each and apply during summer (September to April).

Second to fifth year

- divide the nitrogen fertiliser into 5 equal applications and apply during summer (September to April).

Sixth year and older

- half of the nitrogen fertiliser is applied immediately before flowering and the remainder just after harvesting.

Phosphate (P)

All the phosphate is applied immediately after harvesting.

Potassium (K)

Half of the potassium fertiliser is applied just before flowering and the remainder after harvesting.

Zinc (Zn) and boron (B)

Zinc must be applied at least 4 times a year. The following substances and concentrations are recommended per 100 l of water:

  • Zinc oxide at 200 g or
  • Nitro-Zn at 150 ml or
  • Agri-zinc at 50 ml.

Spray the trees from soon after planting with 100 g borax or 75 g Solubor/100 l water every 2 years.

Organic fertiliser

Kraal or chicken manure can be used as additional fertiliser at 2 or 1 kg respectively per mature (10 years) tree, spread evenly in the drip area. However, if no other fertiliser is available, kraal manure can be applied as follows:

Tree age
(years)
 Kraal manure
 (kg/tree/year)
Time of application

1

5

± 1 kg every 6 weeks from September to April

2 - 3

4 - 5

15

25

Give 5 equal dressings between

September and April

6 - 7

8 - 9

10 - 11

12 - 13

Maximum

40

55

70

80

100

Give 1/2 the quantity before blossoming and the remainder after harvesting

 

Water requirements

  • Litchi trees need regular watering and therefore it is essential that enough water must be available from the flowering stage until after the February/March flush following the harvest.
  • Because the edible portion of the litchi fruit has a water content of 86 %, the availability of water remains important during the development period.
  • A water shortage will delay development of the fruit and adversely affect the size, mass and quality of the litchis.
  • Irrigation must continue after harvesting to ensure that a normal growth flush occurs during February/March, just before the beginning of the dormant period.
  • During dormancy (April to July) irrigation should be reduced, but the tree should not suffer drought.
  • Young trees that are not producing yet are irrigated throughout the year.
  • Producers normally stop irrigating the trees during the coldest months of the year (June and July) so that they can have a proper dormant period. In areas where it is never very cold, irrigation should stop to force the trees into dormancy.

Covering litchi fruit clusters

  • Covering the fruit with paperbags prevents damage from fruitflies and litchi moths, as well as sunburn and cracking.
  • The best time for covering the clusters will vary from one locality to the next.
  • Paperbags are at present the most suitable and also the cheapest covering material.
  • The fruit develops a very attractive red colour inside the paperbags.
  • Covering the fruit also extends the harvest period because fruit can be left on the tree for a longer period.
  • The paperbag at present used is open at both ends. It is made from reinforced brown paper that is very resistant to the elements.
  • The fruit must, however, be covered in the correct way and during the right time of the day (not early in the morning or immediately after rain), because of the risk of decay when covered while still wet. Spray against litchi moth and fruitflies just before covering.
  • Remove all the leaves on the cluster stem before covering.
  • Do not put more than 25 litchis in one bag.
  • The bags must be fixed to hang to an angle to allow water to flow out.
    • Both sides of the bag must be closed and, if necessary, a small opening must be left for rainwater to run out. The open ends can easily and quickly be stapled together.
    • The paperbags will even keep fruit bats and birds away.
    • Another advantage is that the fruit is handled less during harvesting and this limits damage caused by rough handling.
    • When removed carefully, the bags can be used for another season.
    China litchi
    China litchi

Insect pests    China litchi

  • Important pests include bark borers, litchi moth and fruitflies.
  • Consult your nearest extension officer about ways to control these insects.


Harvesting

  • The stage of maturity at which fruit is harvested is one of the most important factors that determine the ultimate quality at the point of sale.
  • Litchis do not develop further after picking. The fruit must therefore remain on the tree until quite ripe.
  • Litchis harvested too early have an unattractive colour and have a sour taste.

When are litchis ripe?

Ripe fruit has an average mass of between 21 and 25 g. Fruit with a mass of at least 21 g is therefore ready for harvesting during a normal season.

Packing

Litchis are packed as loose fruit and all unnecessary twigs or stems must be removed to ensure neat packing. 

China litchi

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