Everything you need to learn about coffee cultivation, harvest and growth.
Introduction to Coffee:
Coffee is a popular beverage possessing a good flavour and stimulating properties. It is prepared by soaking powdered roasted seed of the coffee plant in boiling water. The coffee plant of commerce is stated to be a native of Abyssinia, where it must have been used from very early times.
It is now cultivated in many countries of the world, mainly in West Indies, Brazil, Colombia, Venezuela, Indonesia, India, Sri Lanka, etc. In India, coffee occupies a total area of about 1, 55,300 hectares and its cultivation is confined to the hilly tracts of Western and Eastern Ghats.
It is grown commercially in the states of Karnataka, Tamil Nadu, Kerala and AP. certain other states, namely, Orissa, Assam and MP also grow the crop on a limited scale. The country produces 85,000 to 1,00,000 tonnes of coffee, of which a large portion is exported, enabling it to earn a sizable amount of foreign exchange annually.
Coffee belongs to the genus Coffea of the family Rubiaceae. The genus contains several species, of which only three are of commercial importance. They are C. arabica L. or Arabian coffee, a native of Abyssinia and the source of 90 percent of the world supply; C. robusta Linden, or the Congo coffee, a native of Congo; and C. liberica Bull, ex Hiren. or the Liberian coffee, a native of West Coast of Africa.
The first two are the chief economic species, which are extensively cultivated in India, the areas occupied in the country by Arabica and Robusta being approximately, 90,200 and 65,360 hectares respectively. Of the four states of southern India, Karnataka has the largest area under coffee, which is more than half the total acreage of all these states put together. While Arabica occupies a much larger area than Robusta in every state, where coffee is grown, the position is just the reverse in Kerala.
Coffee Arabica. L. is a beautiful shrub or small tree, varying in height from 4.5 to 9 metres. Leaves stipulate, evergreen and smooth and are borne in pairs. Flowers white, fragrant, star-like and clustered in the leaf-axils; they are bisexual and epigenous. Sepals are 4-toothed. Petals 4-5, connate in a funnel-shaped corolla; lobes contorted.
Stamens 4 to 5. carpels connate in a 2-celled ovary. Fruits (sometimes referred to as “cherries”) small, fleshy berries, the colour changing from green through yellow to red or crimson. Seeds two, greenish-gray in colour, covered with a thin membrane (the silver skin) and enclosed in a dry husk-like parchment.
Coffea Robusta Linden is a larger plant and is more vigorous and more hardy. It is adapted to a wider range of climate. Its leaves are thick and the plant bears heavily. The quality of Robusta coffee is not as good as that of Arabica coffee.
Coffea Liberica. Bull, ex Hiren. is a still larger plant and it attains a height of 12 to 15.2 m. It is more vigorous and less susceptible to diseases. The fruits are 2.54 cm in diameter.
Climate and Soil Required for Coffee Cultivation:
The plant grows well at temperatures between 12°C and 36°C. Humid climate and a well distributed rainfall are quite suitable for cultivation of coffee. The hilly tracts of the Western and the Eastern Ghats, where the cultivation of the crop is mainly carried out, receive an annual rainfall of 1,250 to 3,000 mm. Coffea Arabica grows well at altitudes between 900 and 1,200 m. Of the two species, Arabica is more shade-loving under conditions of southern India.
Coffee requires a deep, friable, porous, moisture-retentive, slightly acidic soil, rich in organic matter. The crop is grown in India in red and lateritic soils. The texture of soil varies from sandy loam to clayey loam and the colour from light grey to deep red.
Cultivation of Coffee:
Propagation of coffee is done by seeds, which are sown in nursery beds for raising seedlings. The soil of these seed beds should be rich in organic matter and free from nematodes and insects. Sheltered land having a gentle slope and a water source nearby is suitable for the nursery.
The soil should be light to medium loam. The area should be provided with a fence to prevent animals from entering it and thus causing damage to the seedlings. A raised seedbed (about 15 cm high) of convenient length and usually of 1 m width is prepared.
Four basketfuls of cattle manure or compost, 2 kg of finely sieved lime and 400g of rock phosphate are added to the soil of a bed, measuring 1 m × 6 m. In the case of heavy soils, coarse sand is added, because this facilitates drainage and aeration.
Seeds are first treated with Agrosan and sown in the nursery in December or January, at a distance of 1.5-2.5 cm from one another in regular rows. They are then covered with a layer of fine soil. In order to prevent drying up of the soil surface and also to maintain even temperature, the bed is covered with a 5 cm-thick layer of paddy straw.
Further, the beds are protected from direct sunlight by an over-head construction, and daily watering is done. Germination of the seeds takes place in about 45 days. During March-May, when the seedlings attain a height of about 5 cm, they are transplanted in secondary nursery beds or individually in nursery baskets or bags, filled with well-manured soil. The seedlings are regularly watered.
When the seedlings are 16-18 months old, the disease-free, vigorous ones among them are selected for planting, which is done during June to September. For this purpose, the soil is levelled and a pit is dug. The seedling is then placed in a hole made in the centre of the pit, which has been filled up, and the hole is covered with soil. The soil surrounding the seedling is packed properly and the level is raised a little higher than the ground level so that water does not stagnate near the seedling. The young plants are tied to stakes for support.
With regard to the bag-seedlings, which are planted in September, the first step is to cut the bottom of the bag and nip the tap-root. The seedling is removed from the bag very carefully without disturbing its soil and root-system and placed in the hole, which is then covered with soil. Certain shade trees like Dadap (Erythrina lithosperma) and silver oak (Grevillea robusta) are planted in the field during June, when the south – westerly monsoon rains begin.
Manuring and Fertilization:
It is necessary to manure the land every year with cattle manure or compost. Certain recommendations have been made in respect of fertilizer application, which are subject to modifications on the basis of soil and plant analyses, soil type, shade intensity and productive potential of the block.
In the case of Arabica coffee, three split doses of N, P2O5 and K2O are applied every year, in March (pre-blossom), May (pre- monsoon) and October (post-monsoon), from the first year after planting up to the fourth year, the total quantities of the three nutrients applied annually being 45 kg, 30 kg and 45 kg per hectare respectively in the first year, 60 kg, 45 kg and 60 kg per hectare in the second and the third years, and 80 kg, 60 kg and 80 kg per hectare in the fourth year.
For the bearing crop (5 years and above), an additional dose is considered necessary in August (mid- monsoon). In regard to Robusta coffee, two doses are applied, one in March (pre-blossom) and the other in October (post-monsoon), the total quantities of N, P2O5 and K2O being 80 kg, 60 kg, 80 kg per hectare respectively. While these two doses are required annually for less than 1,250 kg of crop, the requirements for 1,250 kg of crop and above, which are applied in three doses, in March (pre-blossom), May (pre-monsoon) and October (post-monsoon) are 120 kg, 90 kg and 120 kg per hectare.
It is a common practice to tip the main stem twice. The first tipping is done when the plant attains a height of a little over half a metre and the second one when it attains a height of about a metre and a half. Fruit development starts on one-year old branches, which are pruned after the harvests.
Harvesting and Yield:
Fruit-bearing in the coffee plant starts sometime in the third or the fourth year and continues for 40 years or so. Ripening of the fruits takes about 8 or 9 months. Harvesting of the fruits of Coffea arabica is done during the months of October- December whiles those of Coffea Robusta during January-March.
The average yield of coffee berry is 558 to 670 kg per hectare in the case of C. Arabica and 1,100 to 1,300 kg in the case of C. Robusta.
Quality of coffee depends on different characteristics, namely, appearance when raw, taste when roasted and the qualities of its liquor, which comprise factors, such as aroma, body and acidity. Nutritional factors, weather conditions during development and stages of maturity of the beans can influence the quality.
Although the influence of these factors can be very much reduced by taking recourse to improved cultural practices, it is essential to adopt correct processing techniques so that deterioration in quality does not take place. It is an important point to note that faulty processing can cause deterioration of even the best- quality coffee.
Coffee is processed by two different methods, ‘wet’ method and the ‘dry’ method. Plantation or parchment coffee is prepared by the first method and cherry coffee by the second.
In the ‘wet’ method, pulping equipment and an adequate supply of clean water are required. The berries are fed into the pulper for pulping, which removes the skin and a part of the pulp. They are then placed in vats for fermenting, where the remaining pulp ferments and is washed off in water. The beans are then dried, either in the sun or by artificial heat, after which the brittle parchment is removed by hulling machines and the skin is peeled off with the help of milling machines.
In the ‘dry’ method, the berries are spread evenly with a thickness of about 8 cm on clean drying-ground and exposed to the sun. Tiled or concrete floors are desirable for the purpose. Care is taken to protect the berries from the rain and they are constantly stirred so as to ensure uniform drying. Peeling machines are used for cleaning off the dried skin and pulp and the parchment is removed by pounding in mortars or by other mechanical means.
The seeds, which are more commonly known as “coffee beans”, are then graded and packed in bags for transportation. The beans are eventually roasted and the process reduces the weight while increasing the volume. Many physiological changes take place and the aroma, flavour and colour develop during the process.
Coffee is ground before it is sold to the consumer. The roasted coffee beans contain 0.75 to 1.5 per cent caffeine, the stimulating principle and a volatile oil known as caffeol. This oil is responsible for the aroma and flavour. Besides these, glucose, dextrin, proteins and fatty oil are also present.
Some of the commercially important varieties and selections of Coffea arabica, which are cultivated in India, are Old Chiks, S. 288, Coorgs, S. 795, Kents, and S. 1934.
Diseases of Coffee:
The common diseases of coffee are:
(i) Coffee leaf rust caused by Hemileia vastatrix, which can be controlled by growing resistant varieties and spraying 0.5% Bordeaux mixture.
(ii) Black rot, caused by Pellicularia koleroga, which can be controlled by removing and burning affected parts and applying 1% Bordeaux mixture.
(iii) Anthroacnose, caused by Colletotrichwn gloeosporioides which is responsible for three diseases, namely:
(a) Radcliffe Disease – which can be controlled by pruning affected bushes during February-March, protecting new wood by spraying 0.5% Bordeaux mixture and maintaining adequate shade.
(b) Stalk rot of berries and leaves- which can be controlled by providing good drainage to remove excess water from the root zone and pre-monsoon spraying with 0.5% Bordeaux mixture.
(c) Brown Blight-which can be controlled by maintaining adequate shade and spraying 0.5% Bordeaux mixture.
(iv) Root rots, caused by Fomes spp. and Fusarium spp., which can be controlled by spotting plants with diseased roots and burning them at site and isolating affected patches by digging deep trenches. In the case of Fusarium, the disease can be controlled by removing affected plants and treating the soil at the rate of 1 kg of lime per plant to raise the soil pH and also treating the soil around the affected plant with Para-dichlorobenzene (PDCB) or Brassicol at 0.4%.
(v) Barry blotch, caused by Cercospora coffeicola, which can be controlled by spraying 1% Bordeaux mixture during June and late August and maintaining medium shade overhead.
(vi) Nursery Diseases:
(a) Collar Rot or Damping off-This is caused by Rhizoctonia solani, which can be controlled by Brassicol 0.4% or Rhizoctol 0.5% or Dithane M.22 0.4% and maintaining filtered shade and good sanitation.
(b) Brown Eye-Spot-This is caused by Cercospora coffeicola, which can be controlled by spraying nursery seedlings with 0.4% Flit 406 (Captan) and young coffee plants in the field with 1% Bordeaux mixture during April-May and September-October and avoiding sudden exposure of plants to direct sun.
(vii) Kondli or stem wasting, which is a nonparasitic disorder, can be controlled by avoiding application of copper fungicides to nursery seedlings, particularly in inclement weather during June to August.
Insects Pests of Coffee:
The common insect pests of coffee are:
(i) White stem-borer (Xylotrechus quadripes), which can be controlled by removing and destroying wood and infested parts, swabbing the main stem and thick primary branches with 0.25% BHC (WP), once during April-May and twice during September-January.
(ii) Coffee thrip (Scirtothrips bisponosus, Heliothrips spp., Anaphothrips spp.), which can be controlled by removing weeds that harbour thrips and spraying with 0.03% Phosphamidon or Dimethoate.
(iii) Cockchafer beetle (Phylophaga conferta), which can be controlled by soil treatment with 5% Aldrin or Dieldrin.
(iv) Coffee leaf-minor (Agromyza coffeae), which can be controlled by pruning and destroying affected leaves and spraying 0.1% BHC + 0.1% DDT.
(v) Mites (Oligonychus coffeae, Brevipalpus obovatus), which can be controlled by dusting sulphur or spraying 0.05% wettable sulphur.
(vi) Green and red bugs (Coccus viridis, Saissetia coffea, S. hemisphoericum), which can be controlled by pruning affected parts and spraying 0.03% Dimethoate, Diazinon or Monocrotophos.