Mango

Soils And Climate

Introduction Soil Climate

Introduction

  • Both soil and climate of a ecosystem are the important factors which determine about success or failure of mango crop.
  • Therefore one should give atmost importance to these two factors before establishing a mango orchard.
  • Presently mango is being grown in varied types of soil as well as in different types of climatic conditions across the country.
  • While planning a mango orchard atmost importance should be given to take soil sample and its analysis for pH. nutrient status, EC, water soluble salt content etc.
  • Similarly with respect to climatic conditions temperature, rainfall, wind, hailstorms and altitude of the given place should be considered especially in the selection of a variety.
  • In this chapter the details of all these factors have been discussed at length.

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Soils

  • Mango grows well on all types of soil provided they are deep and well drained.
  • Red loamy soils are quite ideal.
  • Alkaline, ill drained and soils with rocky substratum are not suitable for successful cultivation of mango crop.
  • In India, mango is grown on lateritic, alluvial, kankar and other types of soil.
  • However, rich, medium and well drained soils give better results.
  • Very poor, stony and soils with hard substratum should be avoided.
  • The vigour and cropping behavior of a mango tree are affected by the soil type.
  • In our country the best mango gardens are situated on the deep fertile alluvial soils of the Indo-Gangetic plain.
  • On shallow soils of hill slopes, mango trees grow to a large size but the yields are not satisfactory.
  • On the laterite soils of the west coast and of Bidar (Karnataka) the trees are smaller and sandy loams of Telangana region India, produced trees of medium height.
  • The red soils of Dharwad (Karnataka) and red laterites of Belgaum and Ratnagiri (Maharashtra) and Goa Island (India) are the best soils for mango.
  • Best quality fruits are produced on soils containing 5 to 10 per cent lime and sufficient quantities of peroxide of iron.
  • Under such conditions fruits develop bright reddish tinge.
  • The deep black cotton soils are generally considered not suitable for mango cultivation, since soils are generally avoided for planting mango plants.
  • Such soils need to be reclaimed by leaching out of salts using good quality water, replacing the harmful sodium from the soil with calcium or by establishing effective drainage course to avoid salt build up.
  • However, these are costly and the expenditure is likely to recur as a continuous threat of salinity faced year after year.
  • The mango growing soils should preferably have a very low total water soluble salt content of 0.04 to 0.05 per cent.
  • Fruit crops are most sensitive than cereals and millets.
  • Mango is rated as moderately tolerant to salts with 4-6 dsm-1.
  • The fertility of soil is dependent on its physical, physico-chemical and chemical characteristics.

Physical Characteristics

  • Some of the important factors included under physical characteristics of soil are the slope or contour of the land, soil type, depth of soil and water table.

Slope or contour of the land

  • This is an important factor for successful growth and development of mango crop.
  • The land should be slightly elevated with little slope towards the drain.
  • The drained and basin shaped areas should be avoided because such areas collect more rain water and become water logged.
  • Such situations lead to poor aeration of roots and the roots may turn black and rot, ultimately die.
  • It is a common experience to see that, those trees that are subjected to floods or low lying with poor drainage generally die quickly.
  • This kind of damage has been noticed in the waterlogged areas of Telangana (India). Elevated locations are more ideal for mango cultivation.
  • Soils with too much of slope are prone to erosion and too much of drainage and such soils also get moisture depletion quickly and require frequent irrigations.

Soil profile

  • The fertile soil is the one that is present in the top 15 cm level.
  • It is the cultivated portion of the land.
  • Normally the soil profile is studied from top to a depth of 1.8 m or more.
  • It is a pre-requisite for assessing the suitability of the soil of any crop.
  • The depth, texture, structure and others are also considered.

Depth of the soil

  • Mango has very deep and strong root system thus soils for mango should be quite deep for easy penetration and spread of the root system.
  • Soils with a depth of 1.2 m or more are ideal for mango crop. More the depth of soil, better is the suitability.
  • Hard soils, soils poor in depth or soils having hard pan in sub-soil should be avoided.
  • The deep and well drained soils with no impervious layers, allow good depth and distribution of root system producing trees of standard size, heavy yields and long life.

Texture

  • In India some of the best mango orchards are located in the Gangetic plains of northern India and also on the banks of great rivers of peninsular India.
  • The soils in these regions are highly fertile and silty loams or alluvial loams.
  • Sandy soils are poor in organic matter content and other plant nutrients, as such they need to be supplied by heavy manuring.
  • Such soils do not provide good anchorage to root system.
  • Sandy or gravelly soils have poor water holding capacity.
  • While growing mango in such soils, texture of soil should be improved by periodical application of organic manures like farm yard manure or compost.
  • The most desirable soil for mango is one of medium texture, deep and well-drained.

Structure

  • It refers to arrangement of soil particles.
  • The structure of the soil in different horizons should be open, granular and compact structure should be avoided.
  • The sub-soil should be friable.
  • They should not be impenetrable pans such as clay, Kankar and rocky.
  • The presence of a substratum of loose gravel or murum helps in providing good drainage.

Root penetration

  • It is also a measure of soil aeration.
  • The top 1 m soil should atleast permit the penetration of most roots of plants in plenty.
  • Poor drainage is reflected by the poor growth, sickly appearance or death of plants.
  • Mango being a hardy crop, its roots penetrate easily into hard soils like laterite soil and the plant grows luxuriantly.
  • Many such mango gardens grown on lateric soil can be seen in west coast of India and more particularly in Konkan region of Maharashtra, Goa and coastal Karnataka.

Water table

  • A constant water table is more preferred for good growth and development of mango crop.
  • During any part of the year water table should remain constant and should never fluctuate.
  • For mango the water table should always be at a depth of 1.80 to 2.40 m.
  • If water table is too high then feeder roots will be submerged with water for a long time leading to chloratic patches on leaves.
  • Though the plant may not die but remain unhealthy and growth of the plant is adversely affected.

Chemical Characteristics

  • The chemical characteristics include nutrient status, soil reaction and salt content of soil.

Nutrient status

  • Classification of soils with regard to mango has been done only to certain extent.
  • Nutrient uptake by mango differs with the variety, age of the plant, soil type and management.
  • In general, a crop producing 15 t/ha removes 100 kg N, 25 kg P2O5 and 100 kg K2O.
  • A definite correlation exists between nitrogen, phosphorus, potassium and calcium status of soils and yield of mango.
  • This has been revealed by a preliminary survey of soils conducted in areas of best mango gardens in Bihar.
  • In Tamil Nadu, it was noticed that presence of peroxide of iron in the soil increased the vigour of trees and sweetness of fruits.
  • Most of the mango-growing soils in India have a low soluble salt content, ranging from 0.04 to 0.05 per cent, whereas the total P2O5 varies from 0.06 to 0.0605 per cent, and available K2O from 0.008 to 0.0087 per cent.

Soil reaction

  • The soil reaction or the soil pH affects the growth of mango trees to a certain extent.
  • Highly calcarious soils having large quantities of lime nodules are considered poor for mango cultivation.
  • Being highly alkaline, young plants are subjected to burning.
  • Such soils are rich in sodium and become impenetrable to water.
  • The presence of small amounts of kankar in neutral or slightly alkaline soils upto pH of 7.5 may not harm the tree.
  • A range of 5.5 to 7.5 is ideal for mango growing.
  • The soils should preferably have a very low total water soluble salt content (0.04 to 0.05%).

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Climate

  • Mango is grown in both tropical and sub-tropical conditions.
  • It can tolerate a wide range of climatic conditions.
  • For growing mango on a commercial and profitable scale the temperature and rainfall have to be with in a clearly defined range.
  • In addition to altitude, temperature, rainfall and the wind velocity also influence growth and production of mango. Mango thrives well under humid and dry conditions.
  • It requires good rainfall during its growing season i.e. June to October and rainless, dry weather from November onwards.
  • Rainy or cloudy weather during flowering favours the incidence of powdery mildew disease and leafhoppers.

Altitude

  • The climate of India is more suitable for successful growth and development of mango crop.
  • As a result one can see large number of mango gardens in almost all parts of the country.
  • Altitude of a place is one of the important features of the climate which determines good growth of the crop.
  • The plant grows luxuriantly and yields well from sea level to 1000 m above mean sea level.
  • However, for commercial cultivation of mango crop 600 m altitude is ideal.
  • As the altitude of the place increases over and above 1000 m from MSL the growth and productivity of the crop are poor.
  • The altitude has a definite role on the time of mango flowering.
  • It has been observed that an increase in every 12 m altitude, flowering is retarded by four days.
  • Similarly for each degree latitude, south or north of the tropics, flowering is delayed by four days.

Temperature

  • Climatic conditions particularly temperature, also govern the flowering time and ripening time of fruits.
  • Mango starts flowering early in Bihar, Bengal and eastern Uttar Pradesh due to onset of high temperature early in the season.
  • Fruit ripening is also earlier in these regions than in north-western parts.
  • In the south under moderate temperature conditions even during winter the flowering may start in September or as late as November.
  • At Kanyakumari some of the varieties flower and fruit twice a year.
  • This is known as off-season bearing which may primarily be conditioned by the differences in night and day temperatures and also humidity.
  • The annual mean temperature at which mango thrives best is around 26.70 C.
  • The optimum growth temperature for mango is 23.90 - 26.70 C.
  • Temperature plays a direct role on the flowering, fruit set and fruit development in mango.
  • Under Bangalore (India) conditions mangoes use to flower during November-December months during early 80s and is now shifted to late January.
  • This may be due to diurnal variation in temperature and relative humidity.
  • When atmospheric temperature was high, fruits exposed to direct sunlight were normally affected with spongy tissue disorder.
  • Air temperature of over and above 40.50 C develops spongy tissue in Alphonso mangoes.
  • Exposure of fruits on western side is more dangerous as the fruit on that side getting direct sun rays for longer period are more likely to have spongy tissue.
  • Though fruit splitting in mango is a very rare phenomenon, it is related with variation in maximum and minimum temperature and relative humidity between day and night time.
  • Under Bangalore conditions fruit splitting was around 2 per cent, specially at later stages of fruit development in varieties like, Langra and Amrapalli.
  • It may be due to variation in day and night temperature and relative humidity.
  • After fruit splitting secondary infection occurs in the split portion of the fruit making it unfit for consumption.

Rainfall

  • It is not the quantum of rainfall but the timing which is of importance in growing mango.
  • In India, mango grows equally well both under low and heavy rainfall of 25-250 cm annually.
  • However, with the annual rainfall of 75 cm and above it can be grown with little or no irrigation.
  • One of the Pre-requisites for successful growing of mango is the absence of rain during the flowering time.
  • Rain at flowering not only washes away the pollen, which adversely affects fruit set, but also encourages greater incidence of mango hoppers, mealy bugs and diseases like powdery mildew and anthracnose, which damage the crop sometimes completely.
  • Cloudy weather with resultant increased humidity in the atmosphere also encourages greater incidence of such pests and diseases.
  • This also interferes with the activity of pollinating insects, thus adversely affecting fruit set.
  • In areas of excessive rainfall and high humidity even during the time of fruit maturity, as in Assam, commercial mango growing may not be profitable due to the attack of fruit fly.
  • If high temperature, rainfall and humidity persist throughout the year, there will be no distinct phases of vegetative growth and flowering in the mango tree and bearing will be poor.
  • In the coastal region of Kerala, which has restricted export of mango to the USA, mango gets infested with stone weevil.

Frost

  • Mango is adversely affected by frosts and freezes if not properly protected.
  • The damage depends on several factors, such as the age of the tree, moisture content of the soil, condition of growth, timing, severity and duration of the frost.
  • Generally, young trees with immature wood and those having active growth are affected more severely than the well-grown trees with mature wood and those in dormant condition.
  • Trees identical in growth and age and growing on dry soils are also severely damaged as compared to those growing in wet land.
  • The irrigation raises the soil temperature and provides protection against mild frosts.
  • Early and late frosts cause more damage than the mid-season frosts of the same severity.
  • The trees are affected more severely by the former as they are not fully dormant, while in the latter case damage occurs owing to reinitiation of growth and tenderness of the tissues.
  • Front injury is exhibited through bark splitting, but this is not visible in the young plants.
  • Oozing of gum from stem bark, death of new shoots, charred appearance of leaves and burning appearance of developing fruit buds are the other symptoms of frost injury.
  • If the temperature is below1.10 C, the mango plants are adversely affected by frost.
  • A short spell of -3.30 C and consequent longdrawn out cold spell led to the drying out of the young shoots and leaves of mango plants, killing the tree from the top down to a point where the bark was thick and the sap moved very slowly.
  • The young mango trees in vigorous growth may be injured seriously at 00 C.
  • The minimum temperature of -0.6 to 00 C for 1 hr 15 min for 2 consecutive days resulted in appreciable damage to mango trees.
  • All 1-year-old plants, though protected, were killed completely.
  • Similarly, all 2-year-old plants were found adversely affected and some of these could not survive. Four-year-old plants were partially affected.
  • Differentiating and exposed fruit buds in bud-break and bud-burst stages were killed outright.
  • The turned blackish and dropped down.
  • For protection against frosts, the young mango trees should be covered fairly early and the thatchings should be removed only when the danger is over.
  • Some growers remove the covers too early, with the first warming up of temperatures after winter; but the trees are likely to suffer if late frosts occur.

Wind

  • Exposure to strong winds, whether hot or cool is harmful to mango crop.
  • In fact high velocity of wind affects mango trees in several ways.
  • Winds of high velocity lead to quick evaporation of water from the soil and thus reduce moisture availability which is very much necessary for ideal growth and development of the plant.
  • Mango trees normally assume a dome shaped top and are less prone to wind damage, such as, breaking of limbs, branches, fruit drop etc.
  • Strong winds, gales or storms blow away the branches, leaves or panicles and sometimes fully grown trees also get toppled.
  • It is more so in the areas adjascent to coast or open areas that are not fully protected with windbreaks.
  • Dwarf mango varieties like Amrapali, Rumani and Kerala Dwarf are less prone to wind damage compared to tall and huge trees like Pairi and Langra.
  • High velocity of wind may uproot the whole tree.
  • This problem is commonly noticed in areas frequently affected with heavy cyclone specially in Nellore, Krishna, Ranga Reddy and Viskhapatnam districts of Andhra Pradesh and Kanyakumari district of Tamil Nadu.
  • Fruit drop at various stages of its growth can be noticed due to high velocity of wind.
  • Under Bangalore conditions wind velocity of more than 120 km per hour damaged the Pairi variety mango trees by breaking the limbs.
  • At later stages of fruit development this problem was severe due to heavy weight of the fruit.
  • This necessitates the raising of live, thick and strong windbreaks around the mango orchard.
  • Seedlings of Casuarina, silver oak or Acacia are some of the ideal windbreaks for mango garden.
  • These wind breaks may compete with the mango crop for nutrients and moisture.
  • Thus a trench of half a meter width and half to one meter depth should be dug open between the mango tree rows and windbreak.

Hailstorms

  • Occurrence of hailstorms is a natural phenomena and it causes partial or total loss of mango crop.
  • The hailstorms occur sporadically and that to during the pre-monsoon showers.
  • The damage caused to fruit is by physical hitting of hailstorms, which leads to rupture of tissue and such areas get discoloured and start rotting.
  • Secondary infection by fungus starts sometime after the physical damage.
  • Affected fruits do not ripe and are unfit for consumption.
  • Such fruits are not even fit for pickling.
  • There is hardly any method to protect this damage.

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Andhra Pradesh