Climate requirements

Mango trees can tolerate a wide range of climatic conditions.  The crop is successfully cultivated under conditions which vary from very hot, very humid to cool and dry, to very hot and arid.  The trees can survive in swampy conditions for an extended period of time, but will also survive in areas with an annual rainfall of less than 300 mm and temperatures as high as 45 °C.

 

The average minimum temperature during the winter should preferably be above 5 °C.  Low temperatures when the trees are in full bloom, can cause the fruit to develop to approximately golf-ball size, turn yellow and then be aborted. Large numbers of these fruit result in a reduction in yield.  Mango trees will grow and produce well in areas with very high temperatures (45 °C). However, when the maximum temperature exceeds 46 °C vegetative growth ceases, especially if it is accompanied by low humidity.  For optimum growth and production, the average maximum temperature should be between 27 and 36 °C.  Certain cultivars are less tolerant to high temperatures and low humidity, and the fruit will show symptoms of sunburn (Sensation, Edward, Isis, Fascell and Keitt). Cultivars with a high tolerance include Neldica, Tommy Atkins, Irwin, Lilley, Lippens, Chené, Kent, Ceriese, Kensington, Jubilee, Palmer and Zillate.

 

In South Africa the average relative humidity should preferably be 55 % or less, from October until the fruit is harvested.  The rainfall should also preferably not exceed the following:

 

- September: 50 mm

- October: 85 mm

- November: 110 mm

- December: 140 mm

- January: 140 mm

- February: 140 mm

 

The relative humidity and rainfall described here are ideal for the

development of diseasefree
fruit, but unsuitable for optimum production. Where mangoes are

produced under such
low-rainfall conditions irrigation is of vital importance.

 

Wind (even moderate winds) could cause scratch marks on fruit. Harmful fungi and bacteria can enter the fruit through these wounds. Fruit with such marks are unacceptable for marketing.  Stronger winds will cause fruit loss, resulting in lower yields.  Certain cultivars, such as Zill, Haden and Kent, are prone to a greater extent to fruit loss under windy conditions than others.  Damage by wind can be minimised by:

 

- Avoiding very windy areas.

- Establishing windbreaks such as artificial structures or fast-growing trees on the upwind side of prevailing winds. It is advisable to establish mango orchards in such a manner that the rows run diagonally to the prevailing wind direction to avoid creating a funnel effect.

- Prune the non-bearing flower panicles as soon as it is evident that these will not bear any fruit, because when they become dry and hard, they cause scratch marks on the fruit.

Soil requirements

Mango trees grow and produce well on various soil types. The tree often develops a fairly strong taproot shortly after planting. This taproot can continue growing until it reaches the soil water-table, and under favourable conditions can penetrate the soil to a depth of 6 m. However, most of the roots responsible for nutrient uptake are found in the top 500 mm of soil, with the largest concentrations in the top 250 mm. Depending on the conditions under which the mango is grown, i.e. dryland or under irrigation, the response to the soil type will vary.

 

Soil requirements for cultivation under irrigation

 

- Drainage

Mango trees grow best on a slight slope which enables runoff of excess water and prevents waterlogging. Depressions or basins are poorly drained and plantings on these sites should be avoided. The roots will turn black and become desiccated in oversaturated soils as a result of a lack of aeration. Under such conditions the parts of the plant above the ground will wilt and show symptoms of chlorosis.  Mango trees do not grow and produce well in soils with impermeable layers (mottled layers, usually with a light grey of white colour, hard banks, compacted layers of stratified rocks).

 

They also do not thrive on very steep slopes because excessive drainage in this case could lead to water shortages and soil erosion.

 

- Soil depth

Under irrigation, mangoes grow well in soils with an unimpeded depth of more than 1 m. If irrigation scheduling is well planned, there should be no problem on soil with a depth of 750 mm, provided that any soil or rocky layers that restrict root growth to a depth of 750 mm allow excess water to drain easily. If not, a temporary shallow soil water-table could develop above this layer, with resulting damage to the trees.

 

- Texture

The ideal soil texture for mango cultivation under irrigation is a sandy loam or loam (with a clay content of 15 to 25 %), but soils with a clay content of up to 50 % are also suitable.

 

- Soil structure

The ideal soil has a fairly loose, brittle, crumbly structure.  Compact or strongly-developed soil structures prevent effective water infiltration and root penetration. These soils are normally associated with a high clay content in the subsoil.

 

- Water

Allowing the soil to dry out for 2 or 3 months before the flowering stage will promote good flower formation. This phenomenon is attributed to a simultaneous stimulation of vegetative growth during the autumn months which, in turn, influences flower formation in spring.

 

Fruit drop as well as the size and quality of mango fruit seems to be influenced by irrigation at certain times. Irrigation during the developmental stage of the fruit is essential to prevent fruit drop and to promote the development of young fruit. Additional irrigation from fruit set to ripening results in a considerable improvement in both fruit size and quality.

 

Checmical requirements

 

- Soil pH

Mango trees grow best in soils with pH values of 6 to 7,2. If the soil-exchangeable aluminium (Al) is not more than 30 ppm, soils with a pH of 5,5 or higher may be used.
At pH values lower or higher than 6 to 7,2 the trees may suffer trace-element deficiencies, especially phosphate and potassium.

- Trace elements

A minimum calcium content of 200 ppm is desirable.

The ideal potassium status is from 80 to 200 ppm.
A phosphate content of at least 20 ppm is required.

 

Cultivars

Important characteristics include time of ripening, internal quality, external appearance, fruit size, resistance to bacterial black spot and other diseases, tree size and consistent yields. None of the existing cultivars is totally resistant to bacterial black spot.

 

Tommy Atkins

 

- Early cultivar

- Large fruit (450–700 g) with an ovoid to slightly oblong shape and an attractive skin colour

- Shelf life is good and the cultivar is tolerant to bacterial black spot and anthracnose

- Trees are of average size and produce regular high yields

- Fruit is not entirely fibreless, has a watery taste and is susceptible to internal breakdown, jelly seed and stem-end rot

- Because of its attractive external appearance good prices are realised on both local and export markets

- The cultivar is recommended for planting in all production areas

 

Kensington

 

- Early midseason cultivar with little support in South Africa

- Good resistance to bacterial black spot

- Trees are vigorous and give consistently high yields

- Fruit size is medium to large (> 450 g). Fully-ripe fruit has an unattractive yellow colour with slightly orange cheeks

- Shelf life is good

- Physiological disorders such as jelly seed are rare

 

Kent

 

- Trees are large and give consistently satisfactory yields

- Harvesting period is classified as late midseason

- Fruit is large (500–700 g) with a rounded base, fibreless and the internal quality is very good. The skin colour in cooler, humid areas, is often poorly developed

- Kent is considered as one of the best tasting mangoes

- Highly susceptible to bacterial black spot and is only recommended for hot, dry areas

 

Keitt

 

- Keitt is the latest of all the recommended cultivars

- The fruit size is medium to large (400–500 g). The fruit is fibreless, oval with rounded base.

- kin colour often poor. The fruit has an exceptional keeping quality and can be left on the trees long after normal harvest time without the risk of jelly seed developing

- The trees are of medium size and the growth habit is characteristically open and appears somewhat disorderly with slender ranky branches

- The cultivar is highly susceptible to bacterial black spot and is only recommended for very hot and dry areas