Coconut

Climate And Soils

Climate

But, for ensuring the development of a profitable and prosperous coconut industry, it is necessary that the likes and dislikes of the palm are given due consideration, particularly when establishing plantation in new regions where it was not grown before. In fact, it is highly adaptable to a variety of environments.

• The coconut palm is not very fastidious or exacting in its climatic requirements.
• The coconut palm derives its characteristics from the fact that it is essentially a tropical plant.
• In these connection factors such as latitude, rainfall, temperature, humidity, sunshine, etc., require detailed consideration.

Latitude

• The coconut palm occurs widespread in the tropics.
• The six primary centres of coconut cultivation, viz., Philippines, India, Indonesia, Ceylon, South Sea Islands and Malaya which together account for over 90 per cent of the world's total acreage and production of the crop lie in this zone between 20°N and 20°S latitudes.
• The palm is being grown even beyond this region, as far as 27°N and 27°S, but not on an extensive or commercial scale or with much success.
• In these extreme latitudes the palm is reported to put on good vegetative growth, but not to bear fruits satisfactorily.

Altitude

• The limits to altitude upto which coconut can be grown successfully are set by the latitude also.
• In India, flourishing coconut plantations are met with in parts of Mysore State situated at elevations of 600 m to 900 m above sea level.
• Generally coconut may be possible to grow at elevations higher than 600 m to 900 m in areas near the equator, where the temperature remains favourable for coconut growth.

Rainfall

• All the climatic factors affecting the coconut, rainfall and temperature appear to be the more important ones.
• While temperature conditions may be uniform over comparatively large areas, rainfall will show considerable variation even within short distances.
• The coconut palm can grow and bear fruits with a well distributed rainfall of 100 cm but for profitable cultivation, 100 cm to 225 cm per annum, evenly distributed throughout the year appear necessary.
• It can stand even much higher precipitation if the soil is well drained.
• As the tree stores little moisture and has no tap roots, it is not suited for regions with long and pronounced dry spells during which the water table goes down considerably.
• On the other hand, a water table that is too high and remains stagnant over long periods is definitely harmful to the palm.
• On the West Coast of India wherein lies the major coconut belt, rainfall increases in quantity, from the south to north; but its distribution becomes less and less favourable.
• Thus in Travancore, situated in the south, the annual rainfall is 300 cm or less per annum, but the dry period extends to only two or three months in the year, whereas in the South Kanara District, further north, the annual rainfall is about 350 cm, with the dry or rainless period extending over about five months.
• This difference in the distribution of rainfall is actually reflected in the general productivity of the crop.
• It may be stated in a general way that when the total rainfall falls below 100 cm per annum or where the rainfall distribution is very uneven, the coconut can be grown successfully only under irrigation.
• In parts of Saurashtra and Kutch (India), receiving only 25 cm to 50 cm of rainfall per annum, good coconut garden have been raised because of the availability of abundant supply of sweet water for irrigations.

Temparature

• Temperature is another important weather factor that has great influence on the growth and productivity of the palm.
• In fact it is temperature that actually determines the limits to latitude and altitude.
• The palm requires an equable climate, neither very hot nor very cold.
• The optimum mean annual temperature for best growth and maximum yields is stated to be 27° C with a diurnal variation of 6° C to 7° C.
• Nowhere is the palm being grown extensively where the range of temperature is considerable.
• On the West Coast of India, the monthly mean of the minimum temperature does not fall below 20° C and the monthly mean maximum rarely goes over 32° C.
• High temperatures might cause the young developing inflorescences to dry up, and limit production to those months in the year when the temperature remains at a satisfactory level.

Humidity

• The coconut palm, in general, likes a climate characterised by warm and humid conditions.
• Highly humid conditions are not considered good for the palm from two aspects.
• One is that it reduces transpiration and thereby reduces the uptake of nutrients.
• The other is that it provides congenial conditions for the rapid spread of the fatal diseases of the palm, viz., 'bud-rot' etc.
• The leaf disease of the coconut palm in Kerala (India) is found to spread rapidly during rainy months when the atmospheric humidity is high.
• In Sumatra, too high humidity is reported to cause premature decay of fruit.

Sunshine

• The palm requires plenty of sunlight and does not grow well under shade or in too cloudy regions.
• The lean and lanky growth and unproductiveness of palms growing in shade and the way they try to turn away from obstruction to expose the crowns to the sun, afford sufficient evidence of the avidity of the palm for sunlight.
• Sunlight has also been shown to raise the temperature of the leaf surface and thereby to promote better activity in the tree.
• The importance of sunlight is the synthesis of organic food materials by the chlorophyll of green plants.

Wind

• Dry and windy atmosphere conducive to the best growth of the palm provided soil moisture conditions remain at optimum level, but that where the soil is dry, only little wind is desirable.
• Windiness increases the transpiration rate and helps in the uptake of more nutrients in the soil solution.
• But regions which are subject to frequent violent winds do not appear to be quite suitable for growing the palm.
• Violent storms cause considerable damage to coconut plantations.
• They not only uproot or break the trees but also twist the crown or break the leaves and destroy a considerable part of the crop.

Nearness to sea

• The fact that coconut palm is largely being grown in regions bordering the sea coast has often created a mistaken impression that the palm will not thrive inland.
• However, nearness to sea has considerable effect on the climate as well as on the soil.
• The coastal climate is always more humid and less subject to wide fluctuations of temperature and these conditions are favourable to the palm.
• In the coastal areas, the growth of the coconut is excellent while it is comparatively poor in the interior.
• Another favourable feature of coastal areas is that they generally posses better sub-soil water supplies than those in the interior, because they have at the back of them, higher country and the rain which falls there partly sinks into the soil and moves towards the sea brining with it dissolved nutrients for the palm's nourishment.

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Soil

The coconut, though essentially belonging to the humid regions of the tropics, is a very adaptable palm, which can tolerate a wide range of soil conditions. The crop is grown under extreme conditions of soil which vary from sand to the heaviest clays and on elevations which range from lagoon swampland to hilltops and is found to be exceptionally tolerant to its environment.

• It should, however, be considered a "sea-side palm flourishing in a sea-washed, wellp-drained coast with constant moving water in the soil and in an atmosphere of saline moisture.
• It can, however, grow well on heavier soils provided they are well drained.
• There are vast areas of coastal land throughout the tropics, which have been and could be used for coconut cultivation.
• The coconut palm has been found to growing on all soils irrespective of the parent material from which these soils have originated.
• Thus it has been found to grow well on white or gravelly sand, alluvial soils, laterite or lateritic soils, peaty soils, volcanic and pumice soils and marine and coral soils.
• The best soil, however, for the coconut, is a rich alluvium or loam having proper soil moisture and drainage.
• such as are met with in the backwater areas of Travancore-Cochin, Malabar, South Kanara and the deltaic tracts of the important rivers of India.
• The coconut also thrives and yields well in lateritic loamy, or black clayey soils on bunds of canals, channels or tanks and on the banks of rivers.
• It is also found to come up well on sandy soils especially of the littoral type, provided there is an assured supply of good underground water within easy reach of the roots and the trees are properly manured.

Coconut cultivation on bunds

• In the backwater areas of Kerala it is customary to raise coconut plantations in made-up soils obtained by reclaiming the shallow submerged areas by applying clay and sand in alternate layer and raising the level of the land well above the water.
• There are some of the best and largest coconut garden on this type of soil in Travancore-Cochin.

Coconut soils and nutrient fixation effects

• Soils in which certain plant nutrients are 'fixed' often turn out to be unsuitable for coconut growth unless methods to avoid or minimise fixation are adopted.
• Thus, the red lateritic soils which support a good majority of palms, are often found to be deficient in available phosphoric acid, potash, lime and nitrogen.
• Hydrated iron oxide which is a constituent of laterite soils has the property of 'fixing' or locking up phosphoric acid in forms unavailable for plant use.
• Unless good decomposing organic matter is present and more of these fixed nutrients are constantly released, the palms will deteriorate on laterite soils especially when they are too shallow.
• The decline in growth of palms in laterite soils after an initial promising performance is usually due to this shallowness and the existence of hard pans just below the soil layer, which impede root penetration.
• Pits dug in the laterite area for planting receive 2 kg of common slat at the bottom for softening the rock to aid root penetration.
• Nevertheless, in the adequate attention is bestowed for cultivation and manuring.
• However, large plantation in South India have recently been started on laterite soils.
• A stiff clayey soil particularly with a stiff clay subsoil pan should as a rule be rejected.
• Gravelly soils appear to be quite suitable for coconuts, provided leaching away of nutrients is prevented.
• Increased soil aeration in these areas and wide root spread enable the plant to secure food from a larger range.
• This often counter-balances the natural poverty of these soils. Addition of organic matter helps in their amelioration.

Drainage

• Facility for drainage in the soil is of primary importance.
• Movement of soil water is most essential to ensure proper development and growth of the coconut palm.
• The coconut root is unable to withstand stagnant water whether it be sweet or saline.
• The coconut if given good drainage, is one of the most drought-resisting of trees.
• The essentials for natural drainage, therefore, are a free-working soil of open texture and either a deep water table or else free water movement through the soil.

Soil depth

• The coconut palm requires a good soil depth.
• Even though the palm has an efficient root system, the roots are not strong enough to penetrate any hard layer such as a hard stiff pan of clay or hard laterite.
• Coconuts can flourish and yield normally with a very restricted root system provided the surface soil is physically suitable and chemically rich.

Soil fertility

• An important factor orienting soil suitability for good coconut growth and high yields is tied up with the fertility status of the soils.
• Six principal factors Play major role in relation to coconut cultivation, viz., soil moisture, soil nutrients including the major and trace elements, soil air, soil temperature, root space and the presence of injurious substances toxic to plant growth

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Characteristics Of Coconut Soils

• Major portion of the coconut acreage in India lies in certain well defined zones on the west and east coasts and the table land of Mysore, more than two-thirds of it being in the strip of land between the Western Ghats, and the Arabian Sea.
• Based on the soil, climate and certain other conditions, under which coconuts are grown in India, the area can be grouped into the following well defined zones
• The coastal sandy tract with fairly high water table (1 m to 2 1/2 m) are well defined zones on the west and east coasts of the Peninsula lying mostly in Kerala, Madras, Andhra, Orissa and Bombay.
• The clayey reclaimed areas of the backwaters of Travancore-Cochin and Malabar with high water table (1 m);
• The midland or the upland region lying between the coast and hill slopes of South Kanara and the Kerala area with sandy soil with low water table (about 6m);
• The laterite and loamy soils of hill slopes of the West Coast with varying percentages of gravel and sand with low water table (about 6 m to 9 m);
• The sandy loam soils of Tanjore with high water table during rains and low water table in summer;
• The alluvial deltaic soils of the Godavari ;
• The loamy soils of Mysore, lying at an elevation of about 600 m to 840 m and having a rainfall of 50cm to 100cm but with a fairly good supply of subsoil moisture; and
• The forest soil of Andamans and the coral soils of Laccadives.
• Coconuts grow quite well and yield well in the coastal soil, alluvial and loamy inland soils as well as on laterite and reclaimed soils.
• With suitable cultivation, conservation, adopting ameliorative measures and manuring, all normal soils could be used for coconut cultivation.

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Selection Of A Site For A New Plantation

• The selection of a site for a new plantation is very important and unsuited soil conditions should not prevail in the site selected.
• Any soil type with a definite history of coconut failure should be avoided.
• A preliminary soil survey should very much help in the matter and should include a detailed profile study.
• Soils liable to water-logging, such as low-lying swampy areas, stiff clayey soils with hard pans below, shallow layered laterite soils with hard rock beneath, etc., should not be planted with coconuts.
• Apart from soil suitability, one has to bear in mind quite a number of aspects such as the climate of the region, the liability to danger from diseases, availability of labour, accessibility of supplies and markets as well as cost of the land.
• It may thus be seen that quite an array of diverse factors governs soil suitability for good coconut cultivation.
• Many aspects are indeed involved due to the dynamic nature of the soil system and the heavy demand of plant nutrients of the coconut palm.
• The more the optimum conditions enumerated above are available, the more successful will be the coconut cultivation.

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