Coffee (Revised)

Scientific Name
Coffea spp. (C. arabica L, C. canephora)
Order / Family
Gentianales: Rubiaceae
Local Names
Kahawa (Swahili), Angola: Café (Portuguese), Kafi (Kikongo) Burundi: Akawa (Kirundi) Cameroon: Koffi afan, Caféier (French) (C. arabica) DRC: Kawa (Kinyarwanda)
Pests & Diseases:
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Other pests: Botrytis warty disease, Fruit flies, Sedges, Snails (Giant East African Snail)

Geographical Distribution in Africa

Geographical Distribution of Coffee in Africa. updated on 8th July 2019 source FAOSTAT
© OpenStreetMap contributors, © OpenMapTiles, GBIF.

Other Local names

Ethiopia: Buna (Oromo, Tigrigna, Sidamuafoo) (C. arabica); Bunna (Amharic); Buno (Gedeoffa); Jeno, Jenuai (Sheko) (C. arabica
Egypt: Bunn (C. arabica)
Kenya: Kahawa (Swahili); Kahûa / M ûhûa (Kikuyu)
Madagascar: Kafe 
Mauritius: Caféier d'Arabie, Café; Caféyer (Creole); Copi-cotay (Tamoul) 
Moroccco: Qahwa Kahla (Arabic); Café, (French)
Rwanda: Ikawa 
Uganda: Omwani (Rukiga) (C. Arabica); Bukonzo (Coffee bean): Mwanyi
South Africa: Koffie, Ikhofi (Isizhulu, Ishixhosa)
Tanzania: Kahawa (Swahili)
Togo: Coffi (Tem) (C. canephora)
 

General Information and Agronomic Aspects

Introduction

Coffee are shrubs or small trees that belongs to the family Rubiaceae and the genus coffea. The Rubiaceae family is one of the largest families of flowering plants consisting of around 13,500 species and over 600 genera. There are over 120 species of Coffea within the coffee genus, Coffea arabica (Arabica coffee) and Coffea conephora (Robusta coffee) are the most widely cultivated species and accounts for the majority of global coffee production. C. arabica is preferred for its sweeter taste, while C. canephora has a higher caffeine content and tends to be more bitter. Coffea arabica is native to the mountainous regions of Ethiopia and South Sudan in East Africa. The species was the result of a hybrid between C. canephora and C. eugenioides found in the highlands of East Africa. It thrives in subtropical climates with altitudes ranging from 600 to 2,000 meters above sea level. The species prefers rich, well-drained soil and a moderate amount of rainfall.

Coffea arabica seeds in Kamashi, Ethiopia Ⓒ Maundu, 2014
Coffea arabica seeds in Kamashi, Ethiopia

Ⓒ Maundu, 2014

As a widely consumed beverage, Coffee arabica seeds are roasted, ground, and brewed to create coffee The stimulating effect of the coffee beverage is largely derived from the alkaloid caffeine, but cured beans have to be roasted and finely ground to bring out the characteristic coffee aroma. In some producer countries, roasting of locally available coffee in the home is very common and the brew is prepared by pouring hot water over freshly roasted and ground coffee beans. An important constituent of the coffee bean is caffeine. The free caffeine content in the bean is dependent on the coffee type, variety, the site conditions and other factors, and can be more than 2.5%.
Beyond its use in beverages and food, wood derived from the plant is utilized in the production of high-quality furniture, such as tables, chairs, and other wooden items. Additionally, Coffee arabica offers potential benefits in the field of medicine. It has been traditionally used for its reported analgesic properties, as an aphrodisiac, and as a cardiotonic agent. Other folk remedies suggest its effectiveness against conditions such as asthma, fever, migraine, and opium poisoning, among others. 
Coffee arabica also plays a role in sustainable agriculture practices. The pulp and parchment of the plant are used as organic manure and mulches, aiding in soil improvement. The annual litter from both shade and crop trees, including pruning residues, helps maintain soil organic matter levels, minimizing nutrient leaching and promoting efficient utilization of inorganic fertilizers. Furthermore, Coffee arabica supports intercropping systems, particularly during the initial years of growth. It is often cultivated alongside food crops such as corn, beans, or rice, optimizing land use and potentially providing additional food resources while the coffee plants establish themselves (Orwa et al.,2019, GBIF secretariat, 2021, NCA, 1911, ICO, 2021, ASARECA, 2019).
Coffee is one of the most important cash crops in Kenya. It is grown in large-scale plantations (42,000 ha from 2001-2005) as well as by small-scale holders (128,000 ha) giving a total production of about 50,000 tons annually. The main variety in Kenya is Arabica coffee (C. arabica). 

The stimulating effect of the coffee beverage is largely derived from the alkaloid caffeine, but cured beans have to be roasted and finely ground to bring out the characteristic coffee aroma. In some producer countries, roasting of locally available coffee in the home is very common and the brew is prepared by pouring hot water over freshly roasted and ground coffee beans. 

An important constituent of the coffee bean is caffeine. The free caffeine content in a bean is dependant on the coffee type, variety, the site conditions and other factors, and can be more than 2.5%. 

Economically, the most important coffee varieties are Coffea arabica called "Arabica" and Coffea canephora called "Robusta". The latter yields about 30% more than "Arabica", albeit its price is around 30% lower. 

Species account

Coffea arabica -is an evergreen shrub or small tree that grows to a height of 5 m. Leaves: simple, alternate, opposite, dark green, glossy surfaced and ovate in shape, with prominent central vein. Flowers:  small and white. sweet scented, star-shaped and carried on stout but short peduncles. Fruits: edible red or purple, indehiscent drupes, oval shaped berries that contain two seeds each. 
The coffee berries are picked when ripe and depulped, the extracted seeds/beans then dried, roasted and ground to produce coffee, which is one of the most widely consumed beverages in the world. The plant is also used in traditional medicine to treat various ailments, including headaches, fever, and fatigue. C. arabica seeds contain caffeine, which has been described as a natural herbicide, selectively inhibiting germination of seeds of Amaranthus spinosus. Additionally, C. arabica is cultivated for its ornamental value, and its leaves used to make herbal teas (GBIF secretariat, 2021, Orwa et al, 2019).

Coffee beans-bun Ⓒ Adeka et al, 2005
Coffee beans-bun
Ⓒ Adeka et al, 2005

Fresh and roasted Coffea berries in Kamashi, Ethiopia Ⓒ Maundu, 2014
Fresh and roasted Coffea berries in Kamashi, Ethiopia
Ⓒ Maundu, 2014

Related species. 

Coffea canephora, also known as Robusta coffee, is a small tree or shrub that typically grows up to 10 meters tall with dark green, glossy leaves. Coffea canephora produces small, white flowers that are followed by green, oval-shaped fruits that turn red when ripe. The fruit, or cherry, contains two seeds or beans, which are the part of the plant that is harvested for coffee production. The species is predominantly grown in low-altitude, humid tropical areas and contributes to approximately 30% of global coffee production. Major producers of Robusta include Brazil, Indonesia, and Cote d'Ivoire, while its cultivation has expanded to Southeast Asia, specifically the Philippines and Vietnam, as well as India.
Robusta coffee is unique from other coffee species, particularly Coffea arabica, in several ways. For one, it is known for its high caffeine content, which can be almost double that of arabica beans. Robusta beans also have a more bitter taste and are generally considered to be of lower quality than arabica beans. However, C. canephora is more resistant to pests and diseases, making it easier to cultivate in certain regions. C. canephora is primarily used for the production of instant coffee and lower-quality blends. It is also used in espresso blends to provide a strong, bitter taste. Robusta beans are generally less expensive than arabica beans, making them a more affordable option for coffee producers. However, the lower quality and less complex flavor profile of C. canephora means that it is not as highly valued in the specialty coffee market (Chadburn & Davis, 2017, Dussert, et al.,2003).

Coffea eugenioides- is native to the highlands of East Africa, where it occurs in the eastern part of the Democratic Republic of Congo, Rwanda, Uganda, Kenya and western Tanzania (Charrier, A., 2002). C. eugenioides is a common understorey species found in the form of a shrub, usually 2–3 m in height, with more than one main stem. When growing under shade in natural forest, it resembles a miniature 'Coffea arabica': the leaves are similar, but they are smaller and thinner; the flowers also resemble those of Coffea arabica, but they are smaller and there are seldom more than 2 or 3 in a cluster. The fruits are not abundant and contain very small beans. When Coffea eugenioides is growing in the open (e.g., in living collections) it becomes a compact conical shrub or small tree, with small leaves (Charrier, A., 2002).

Coffee varieties 
Arabica and Robusta coffee are further divided into multiple varieties. The flavors of these coffees can vary greatly depending on the growth conditions of the coffee, including altitude, soil type, and climate.

Table 1: Kenya coffee varieties. 

Variety

Altitude

Spacing Density

Attributes

'Ruiru II'

All coffee growing areas

2 x 2 m 
(6 x 6 ft)

2500 trees/ha

  • Resistant to coffee berry disease and leaf rust

  • Early maturing (18-24 months)

  • Cost effective - reduces costs by 30%

  • High yielding, high quality

'SL 34'

High altitude with good rainfall

2.75 x 2.75 m 
(9 x 9 ft)

1330 trees/ha

  • High yielding

  • High quality

  • Susceptible to Coffee Leaf Rust and Coffee Berry Disease

'Sl 28'

Medium to high altitude coffee zones without serious leaf rust

2.75 x 2.75 m 
(9 x 9 ft) 

1330 trees/ha

  • High yielding

  • High quality

  • Susceptible to Coffee Leaf Rust and Coffee Berry Disease

'K7'

Low altitude

2.75 x 2.75 m 
(9 x 9 ft)

  • Tolerant to Coffee Leaf Rust

  • Tolerant to drought

  • High yielding

  • High quality

Batian

 

 

  • It is resistant to Coffee berry diseases and Coffee leaf rust.

  • Gives farmers a high yield; with a plant density of 1900 trees per hectare.

  • Ripening of cherries comes earlier than the traditional varieties.

  • The bean size is bigger than other Kenyan varieties.

  • Quality is high; it even competes with the SL28 and SL34.

  • The crop is sensitive to acidic soils

Source: Trabocca. (n.d.). Kenyan coffee varieties: https://www.trabocca.com/coffee-knowledge/origin/kenyan-coffee-varieties-a-comprehensive-overview-of-the-top-varieties/

The coffee industry in Uganda primarily focuses on two popular Robusta varieties: Nganda and Erecta, which together make up about 80% of the country's coffee production. Additionally, Uganda also produces a smaller amount (around 20%) of Arabica Typical varieties, including SL 28 (grown at high altitudes), SL 14 (grown at medium altitudes), KP 423 (grown at medium altitudes), and Kent varieties (You Well n.d)

Ecological information
The ideal temperature range for Arabica coffee lies between 18 and 24°c. Maximum Day temperatures should not exceed 30°c and night temperatures should not fall below 15degC. At higher temperatures, bud formation and growth are stimulated. Low temperature or wide daily temperature variation may result in distortion, yellowing and cracking of the leaves and tip growth, a condition known as "Hot and Cold" or crinkle heat. Arabica coffee is normally grown at altitudes from 1400 to 2000 m (4,500-6,800 ft) with a rainfall of not less than 1000 mm per year. Where coffee is grown under conditions of minimum rainfall, mulching is essential to conserve moisture. 
Robusta coffee is more resistant to pest infestation and is well adapted to warm and humid equatorial climates with average temperatures of 22-26degC, minimum not below 10degC at altitudes of 100-800 m, and well-distributed annual rainfall of 2000 mm or more. The ideal amount of rainfall lies between 1500 and 1900 mm. Coffee reacts positively to a drought period, which should nevertheless not be longer than 3 months. The rainfall should be evenly spread throughout the rest of the year. Irregular rainfall causes uneven blossoms and fruit maturity. Coffee is a half-shade plant, which can only utilize around 1% of the sunlight for photosynthesis. At leaf temperatures over 34o C, assimilation is practically zero, meaning that the rate of photosynthesis of a shaded plant is actually higher than that of a plant fully exposed to the sun. 
As a rule: Grow Robusta in lower regions and Arabica in higher regions. The borderline is variable, and lies around 1400 m in Kenya. The berry borer and coffee rust are important indicators as to whether the coffee variety is suited to the site conditions. For example, an Arabica plantation at 1200 m, which is heavily infected with coffee rust and infected by berry borer, despite sufficient shade, is an indication that the variety is ill-suited to the site, and should, in time, be replaced with Robusta. 
Coffee prefers well-drained and airy soils. It needs free drainage to a depth of at least 1.5 m and 3 m in drier areas. Humus-rich, lightly acidic soils (pH range 4.4-5.4) are beneficial; the best conditions are those to be found on virgin soils of volcanic origin. The topsoil should contain at least 2% humus.

Agronomic aspects

Vegetative propagation can be done by rooting of cuttings, grafting, top-working and micro propagation (tissue culture). Major considerations for vegetative propagation are: 
 
Choice of mother trees.
•  These trees are derived from seedlings that have undergone a pre-selection test for coffee berry disease and coffee leaf rust resistance.
•  Establishment of a clonal garden. The selected mother trees are established in the field as per the recommended spacing of 1m x 1m. After 12-18 months, the primary branches are removed and the stems bent and pegged down in a horizontal position to encourage growth of orthotropic (vertical) shoots.
Construction of a propagator:
•   The propagators whose width measures 0.75 m (2.5 ft) are constructed on a 60 cm foundation with a wall that rises another 50 cm above the ground.
•  To achieve good drainage, the first 15 cm from the ground level are filled with gravel covered by a layer of sand of about 7.5 cm. Finally, a 15 cm rooting medium is placed on top of the sand. Recommended rooting media is either of the following: a) sawdust from cypress trees, b) pure river sand or c) sub-soil, all free from any contamination.
•   The propagator should be provided with a watering system (mini sprinklers) with emitters at 150 cm spacing.
• To regulate relative humidity, the propagators are covered with clear polythene sheeting, gauge 1000 suspended 1 m above the rooting medium on steel or wooden frames. Shade is normally erected about 2.75 m (9ft) from the ground. The recommended materials for shade are sisal/bamboo poles, shade net (75% shade) or interwoven nets.
 
Propagation of rooted cuttings:
•   Suckers are harvested from the mother trees when they are 6 months old and bearing 6 internodes. Harvesting is done early in the morning when the atmospheric relative humidity is high.
•   Single node cuttings are prepared by making a cut at an angle below the node but retaining the pair of leaves.
•    The cuttings are planted in propagators at a depth of 2-4 cm and a spacing of 4 cm x 4 cm. Callus formation begins 3 weeks after planting and is complete in 5-6 weeks. (callus formation is the healing of the cut edge of the cutting in the rooting media).
•    Root development follows after 8-10 weeks
•   The rooted cuttings are transplanted at 12-14 weeks into black polybags measuring 12.5 x 22.5 cm (5x9 in), 200 gauge filled with rich composite soil mixture consisting of top soil, river sand and well-rotted manure at a ratio of 3:2:1 respectively, all free from any contamination. For organic propagation rock phosphate is added and if insects normally pose a problem, incorporate chopped leaves of Lantana camara or Mexican marigold.
•   The potted seedlings are returned to the propagators for a period of 1-2 months to develop more foliage and feeder roots under the same environmental conditions.
 
The planting materials are then taken care of as per the nursery recommendations.
•    Grafting: This is the successful healing of the union between the scion and the rootstock. Grafting requires 10–12-month-old seedlings (or pencil thick) to be used as rootstock. Rootstocks of the commercially existing Arabica varieties are compatible with 'Ruiru II'. The graft union is tied with a polythene tape and the entire seedling is placed in a propagator to heal. 
•    Topworking: This is a cheaper method of converting mature old trees of traditional Arabica coffee into 'Ruiru II' without uprooting and replanting. Sucker growth is induced on the trees to be converted by side pruning. Six-month-old healthy suckers are selected and grafted with single node scions of 'Ruiru II' bearing a pair of leaves. The graft union is tied with polythene tape to keep the scion in place. Advantages of Topworking:
•    A farm can be converted from the traditional cultivars ('SL 28', 'SL 34' or 'K7') to 'Ruiru II' without interfering with normal cropping pattern.
•    The farmer saves on cost of uprooting old bushes and new establishment costs.
•    The well-established root system of old stumps prevents lodging, which may occur when young "Ruiru II" trees carry a heavy crop.
Coffee Nursery Management
Most cultivars of the self-pollinating Arabica coffee are practically pure lines, propagated by seed. In Kenya, F1 hybrid seeds are produced by hand-pollination of new disease-resistant Arabica cultivars, and certified seed can be obtained from the Coffee Research Foundation in Ruiru. 
•    The nursery site should be selected on level to gently sloping ground. On sloping ground of 4-5 % it should be bench terraced, sheltered from strong winds, near a permanent reliable water source, accessible and free from weeds.
•    The bed construction should be 1m (3 ft) wide with a shade 60 cm (2 ft) above the bed.
•    Plant only certified disease-free seed from the Coffee Research Foundation (CRF). Sow immediately after collection to avoid loss of viability in order to ensure high germination rate. Remove the husks to reduce germination period. 1 kg seed contains an average of 3,000 seeds.
•    Germinate in river sand beds of 5-7 cm (2-3 in) depth with a spacing of 2.5 x 2.5 cm (1 in) and 1 cm (1/2 in) deep. Apply a thin mulch cover. Shade 60 cm above the bed. Water adequately (avoid waterlogging)
•     Remove mulch when seeds have germinated.
•    Seedlings emerge after 4 weeks and take another 4 weeks before they are transplanted to polybags
•    Transplant pre-germs at the leaf stage into polybags. Avoid deep planting. This ensures minimal disturbance to roots during transplanting, and makes long distance transportation more convenient. Also field establishment can wait till the weather is favourable.
•    Renew seed bed and river sand every time new seeds are being planted
•    Potting mixture: top soil: 3, sand: 2, well-rotted manure or compost: 1. To this mixture add phosphorous, for organic farming a handful of rock phosphate to about 6 "debes" (debe = 20 litre bucket) of mixture as well as neem cake or chopped up leaves of Mexican marigold or Lantana camara for insect control.
•    Water seedlings at 2 times a week and control weeds by hand weeding. Control diseases (damping off, leaf rust and Brown eye spot) using 0.5 % Copper solution, and control insect pests when noticed.
•    Shading. Put a shed at 120 cm (4 ft) above the polybed, and provide dense shade initially. Harden the seedlings by gradually reducing the shade. Reduce the shade by half when the seedlings are 8-9 months old and completely 1 month before transplanting. farmyard manure or well-rotted coffee pulp plus 200 g rock phosphate. If the soil is acidic add 100 g dolomitic limestone (CaCO3 MgCO3). 

Land preparation
Land cleared of trees within 6 months should not be used for coffee because of the risk of Armillaria, a fungal disease which causes root rot.
Clear land well in advance, digging out all stumps, bushes and grasses such as kikuyu grass and couch grass. If the land has steep slopes, make terraces or other conservation structures. Protect bench terraces by planting grasses e.g., Paspulum notatum on the bench faces. Planting holes should be dug 3 months before the onset of rains to allow weathering.
Fill the holes 4 weeks before planting with a top soil mixed with 1 "debe" (20 litre bucket) farmyard manure or well-rotted coffee pulp plus 200 g rock phosphate. If the soil is acidic add 100 g dolomitic limestone (CaCO3 MgCO3).

Planting 
Dig holes of size 60 cm x 60 cm x 60 cm at a spacing of 2.75m x 2.75m for the traditional varieties ("SL28", "SL34" and "K7"). A closer spacing of 2m x 1 m on flat land for small holders without spray roads is recommended. Spacing for "Ruiru II" is 2 x 2 m or 2 x 1 m giving a population density of 2,500 - 3,300 trees/ha for small holders. Transplant potted seedlings when they are about 30-40 cm high with maturing bark about 15 cm (6 in) and 2-3 pairs of lateral branches at about 12-15 months old. 

Mulching 
Mulching has several benefits to coffee e.g. conservation of moisture during dry spells, suppression of weed growth, nutrient supply, improvement of soil structure and water infiltration, checking of soil erosion and top soil temperature as well as reduction of thrips incidence. Mulching also enhances root development in the fertile top soil and thus a general yield increase. Examples of mulching material include Napier grass (half an acre of Napier grass gives enough mulch for 1 ha (2.5 acres) of coffee land), sisal waste, coffee prunings, maize and banana trash. When using coffee prunings, take care that no pests (leafminers, mealybugs, etc.) are on the prunings otherwise they could re-infest the trees. 

Shade trees and windbreaks 
Plant shade trees 1 year before coffee transplanting is required. Common shade trees are leucaena (Leucaena leucocephala) and mother of cocoa (Gliricidia sepium). Also Grevillea robusta, Albizia sp. and Cordia abyssinica are recommended shade trees. (See also below under Diversification Strategies). With intensive cultivation and optimum inputs, higher yields are obtained with unshaded coffee, but shade will prevent overbearing and shoot dieback under lower standards of crop management or suboptimal ecological conditions. 
 
Husbandry
Coffee grows best with shade trees. Shade trees reduce stress in coffee. Avoid extracting timber at random for short-term gains. Maintain a two-layer canopy consisting of temporary and permanent shade trees like coconut, Ficus species, Albizzia species, jack fruit, and citrus, etc. At higher altitudes temporary shade trees may be phased out once the coffee is well-established. Regulate shade every year instead of once in 3-4 years to minimize damage to coffee bushes. Shade tree selection and management are important because better shade may decrease the incidence of some important pests and diseases. Suppressing of weeds, particularly East African couch grass (Digitaria scalarum) and Kikuyu grass, by careful tillage (not damaging the superficial feeder roots of the coffee), mulching and/or leguminous cover crops, is very important. 
Fertiliser requirements depend on crop level and nutrient status of the soil. Nutrients removed by harvesting 6 t of fruits of Robusta coffee, equivalent to 1 t of green beans, are: 35 kg N, 6 kg P2O5, 50 kg K2O, 4 kg CaO, 4 kg MgO, 0.3 kg Fe2O3 and 0.02 kg Mn3O4. Return coffee pulps and hulls as organic fertilizer in coffee fields. These are rich in nutrients. A 60 kg bag of coffee pulps/hulls contains: 1 kg N; 0.60 kg P; .09 kg K and other trace elements. 
Mulching using dried banana leaves and cut dried grass conserves soil moisture, protects soil from compaction, and reduces soil acidity. 

Pruning
Pruning is essential in coffee production:
(a) to determine the shape of the tree
(b) to maximise the amount of new wood for the next season's crop (c) to maintain a correct balance between leaf area and crop and
(d) to prevent over-bearing and thus reduce biennial production or death of trees.
Unpruned coffee usually produces a heavy crop one year and a lighter crop the next season. Pruning makes trees more manageable and easier to pick and spray. Diseases and insect pests can also do more damage in unpruned coffee, as they tend to build up in the older branches.
 

A well pruned, young coffee plant (Coffea arabica) .

A well pruned, young coffee plant (Coffea arabica) .

Advantages include:
•    Suitable crop: leaf ratio
•    Uniform yearly cropping
•  Good light and air penetration and circulation for better fruiting and bringing vigour to the tree
 
When to prune:
Immediately after main crop harvesting. Sick-looking trees due to die back to be pruned only after new growth. Trees attacked by star scales to be pruned after the main crop to avoid carrying the scales to other trees.
Multiple stem pruning: The tree normally has 3 stems and the crop is borne on laterals. Each.lateral bears 2 crops and is then pruned. The crop is therefore borne higher up the tree each year. Every 4-6 years a new cycle is started. This is done by selecting 3 new suckers, which will replace the original stems. In multiple stem pruning, 4 basic operations are carried out:
1. Main pruning: Regulating the number and spacing of primary branches. 
2. Secondary pruning: Also known as "handling", involves regulating number and spacing of secondary branches. 
3. Sucker control: Removal of unwanted growing shoots called "suckers" (remove them with the meristem, otherwise you multiply suckers)
4. Change of cycle: Selection of some "suckers" to grow into new bearing stems. 

How to prune: 
Please discuss with a CRF (Coffee Research Foundation) field officer or read CRF Technical Circular No 301: Canopy Management in Coffee, as the recommendations differ from different ecological zones.

Diversification strategies
1) Crops of the upper storey (shade)
They create large amounts of organic material and humus and at the same time protect the coffee tree against too much sun. The alternation in yield can be reduced, and the life-time of the plantation is increased. Shade also has an immense influence on the quality of the coffee, but it also reduces the yield (fewer coffee trees per area unit). Shading trees also reduce weeds: When an optimum density of coffee and shading trees is reached, tilling weeds is hardly necessary anymore. Shading trees protects against soil erosion and improves the micro-climate on the plantation. By choosing the correct varieties and cultivation method for the shading trees, the micro-climate can be influenced at any point in time. This is very important to regulate pests. Fruit trees offer a diversification for the farmer's diet and economic base. Precious woods can provide a long-term increase in value of the site: along with other varieties, they can provide wood for construction and fuel. Shading trees also creates more pleasant working temperatures on the plantation. 
No figures can be offered for the optimum shade density, as this depends on the local site conditions and the state of the plantation. A rule of thumb says that the shade should be around 50%. The higher in altitude the coffee plot lies, the less the distances should be between the coffee bushes and start of the shading roof. At the upper growth limits for coffee plants, the shading plants are therefore at around the same height as them. Care should be taken to trim the shading plants synchronously to the coffee blossoming (6-8 weeks before the blossom). Blossom formation can thereby be assisted and synchronized. 
 
2 ) Crops of the middle storey 
As with the shading plants, the variation of varieties used for the middle crop should be adapted to the local site conditions. They can be chosen according to the need for fruits and additional products for each individual plantation. Bananas should, if possible, always be integrated as an additional crop. They are well suited to providing temporary shade, and for 'drying out' of the wetter parts of a plantation. Their ability to mobilise potassium reserves in the soil, and to make them available for the coffee trees is very important. A whole diversity of combinations with other fruit trees can be integrated into the system: citrus planted together with avocado, are especially good for sites that enjoy intensive sunlight. 
 
3 ) Crops of the under storey
On sites which are not optimal (e.g. too dry or poor in nutrients), it makes sense to replace the natural vegetation in the under storey with green manuring plants (legumes). The bottom crops should never be allowed to dominate and completely displace the natural vegetation. Many varieties are suitable as bottom crops. They should be selected according to the amount of shade they provide, soil conditions and rainfall. In principle, bottom crops should be sown on new plantations, or when the shading trees and coffee bushes are being trimmed. Otherwise there will not be enough light on an organic coffee plantation for the bottom crops. It is very important to sow perennial, non-climbing and not very aggressively growing legumes. Otherwise there is a danger of the coffee plantation becoming overgrown e.g. with tropical kudzu (Pueraria phaseoloides).
 

Harvest, post-harvest practices and markets 

Harvesting 
Each year coffee is harvested during the dry season when the coffee cherries are bright red, glossy, and firm. To maximize the amount of ripe coffee harvested it is necessary to selectively pick the ripe beans from the tree by hand and leave behind unripe, green beans to be harvested at a later time. Selective picking of coffee berries at 10-14-day intervals is common where harvesting extends over a period of 7-9 months. Where the harvesting season is shorter, whole branches are stripped when the majority of berries are ripe. Costs of harvesting will be 2-3 times higher for selective picking than strip picking. Deliver berries for processing the same day they are picked. Pulping must be done on the day coffee is picked as coffee left in the sun will start to ferment. Pulping is done to remove exocarp and mesocarp through the wet processing method after which coffee parchment is obtained. The parchment is then dried in shallow layers on raised tables or trays to moisture content of 10-11%. For more information on processing, please contact Coffee Research Foundation (CRF), Ruiru.

Quality problem
Stinkers are a severe form of over fermented beans. These defective beans will give a bad (unclean, over fermented, pulpy, sour, foul) taste to brewed coffee and will down grade the delivered coffee, causing loss of considerable earnings. Long fermentation times (more than 4 days) and hot temperatures are the main culprits producing these unpleasant beans. 

Child roasting Coffea arabica seeds in Kamashi, Ethiopia Ⓒ Maundu, 2014
Child roasting Coffea arabica seeds in Kamashi, Ethiopia

Ⓒ Maundu, 2014

Storage 
Coffee stores should be dry, clean and well ventilated. Never store or keep chemicals in a coffee store. Keep fully dry coffee beans on wooden tables or floors or even in ventilated bins. They should be stirred or turned every day for 10 days before bagging. They must be put in sacks as they come from the drying tables. Place bags on wooden battens 15 cm above the ground or concrete floor and away from walls. Do not store close to corrugated iron sheets. Store for a minimum of 4 weeks and a maximum of 6 months. After that beans become woody. A relative humidity in the store of 60% at 20degC is suitable.

Value addition and markets 

Coffee is a highly consumed and traded beverage worldwide. Top coffee producers include Brazil, Vietnam, and Colombia, while major consumers and importers are the European Union and the United States1. Among all continents, Africa boasts the highest number of countries engaged in coffee production. Ethiopia is Africa's top coffee exporter, earning approximately $1.2 billion in annual coffee exports. Uganda follows as the second-largest exporter with around $594.2 million, as per Statista data 2. 
Coffee undergoes value addition to create various products, adding to its market value. Some of the products generated from coffee include roasted coffee beans, instant coffee, coffee extracts, coffee-based beverages, and specialty coffee blends. These value-added coffee products cater to different consumer preferences and offer unique taste experiences (1fao.org, 2 African Business).

Nutritional value and recipes

Coffee contains a range of vitamins and minerals that can be beneficial for health and energy, as well as being very low in calories. Coffee is a popular beverage consumed all over the world, known for its stimulating effect on the central nervous system due to the presence of caffeine. It contains several key nutrients and bioactive compounds that can provide certain health benefits when consumed in moderation. The protein, mineral, and vitamin profile of a coffee can vary based on the different coffee types.
Nutritional Benefits:
•    Protein: Coffee contains a significant amount of protein, which is important for building and repairing tissues in the body3.
•    Minerals: Coffee is a good source of several minerals, including Calcium, Essential for bone health, muscle movement and regulation of normal heart rhythms and nerve functions. Iron: Important for oxygen transport in the body. Magnesium, which is important for bone health, Phosphorus important for growth, maintenance, and repair of all tissues and cells, and for the production of the genetic building blocks, DNA and RN and potassium, which can help to regulate blood pressure3.
•    Bioactive Compounds: The bioactive compounds in coffee, such as chlorogenic acids, may help to reduce the risk of chronic diseases, such as type 2 diabetes and cardiovascular disease3.
Coffee consumption has been linked to several potential health benefits. These include protection against type 2 diabetes, Parkinson's disease, liver disease, and liver cancer. Additionally, coffee may contribute to cardiovascular health1,2.
It is important to note that coffee should be consumed in moderation, as excessive caffeine consumption can lead to negative side effects, such as increased heart rate, anxiety, and insomnia. Additionally, some people may be sensitive to the acidity in coffee, which can cause gastrointestinal discomfort (1cafearabo.com, 2verywellfit.com, 3homegrounds.co).
Proximate nutritional composition 100 g of edible portion of Coffee, instant, dry powder or granules



Proximate composition and dietary energy


Coffee, instant, dry powder or granules


Recommended daily allowance (approx.) for adults a


Edible conversion factor,


1

 

Energy (kj)


1310


9623


Energy (kcal)


311


2300


Water (g) 


2.7-3.4


2000-3000c


Protein (g)


16.1


50


Fat (g)


1


<30 (male), <20 (female)b


Carbohydrate (g)


50.4


225 -325g


Fibre (g)


3.6


30d


Ash (g)


9.9


 


Mineral composition


 


 


Ca (mg)


140-150


800


Fe (mg)


3.1-4.6


14


Mg (mg)


330-370


300


P (mg)


310-330


800


K (mg)


3600-3780


4,700f


Na (mg)


81-84


<2300e


Zn (mg)


0.32-1.1


15


Se(mg)


9


30


Bioactive compound composition


 


 


Vit A-RAE (mcg)


0


800


Vit A RE (mcg)


0


800


Retinol (mcg)


 


1000


β-carotene equivalent (mcg)


0


600 – 1500g


Thiamin (mg)


0


1.4


Riboflavin (mg)


1


1.6


Niacin (mg)


42.9


18


Folate (mcg)


13


400f


Vit B12 (mcg)


0


3


Vit C (mg)


2


60

Source (Nutrient data): FAO/Government of Kenya. 2018. Kenya Food Composition Tables. Nairobi, 254 pp. http://www.fao.org/3/I9120EN/i9120en.pdf

a Lewis, J. 2019. Codex nutrient reference values. Rome. FAO and WHO

b NHS (refers to saturated fat)

c https://www.hsph.harvard.edu/nutritionsource/water/

d British Heart Foundation

e FDA

f NIH

g Mayo Clinic

Recipes
Coffee (Buna in Amharic)

In Ethiopia coffee beans, bun are roasted on a pan to dark brown colour. It is spiced and ground on stone to granules. The coffee is served in a kettle (jebena, gebena). The first round of coffee is strong. Subsequent ones are milder as one keeps on replenishing with water, more sugar and then boiling. Coffee taking is an important occasion in many communities in Ethiopia and northern Kenya and is an important drink in some ceremonies. Among the Somali, coffee is served in small cups with date fruits or xalwa. In Sudan, coffee (bun) is popular during harvesting, weddings and house construction ceremonies.
Ground spices such as ginger (tangawizi) and cinnamon (mdalasini) are often used to spice coffee.
Ingredients and equipment
Jebena (pot for brewing coffee)
3 Seni (small cups)
1 cups of water
Ethiopian Coffee roasting pan 
Coffee grinder or mortar and pestle
½ cup of green beans 
1 tablespoon of salt
1 tablespoon of sugar

Wash the coffee beans about 3-4 times
Place the beans in a pan and roast on medium flame
Roast for about 10 min as you stir and shake the pan. The beans change to dark brown and release a strong aroma.
Using a coffee grinder or mortar and pestle, grind the beans to fine coffee.
Heat water in the Jebena
Add coffee into the jebena and heat with medium heat. Close the spout but open when the coffee starts to boil.
Remove from fire, cover the spout and let the coffee granules settle.
Serve the coffee in sini cups
Flavour the coffee according to your liking

Coffee may be taken black or with milk. Among the Muslim community of the coastal East Africa, very strong coffee is served in small cups (kahawa chungu) especially in the streets in the evenings and early in the morning.

Information on Diseases

General information

Conventional coffee plantations are generally confronted with many pests and diseases. In practice, on ecological coffee plantations, the following may be of relevance. An infestation of either pests or diseases is always an indication that the coffee eco-system is not balanced, and the causes must be investigated.

Possible causes are:

  • The site is not suitable (too low altitude, too warm, too humid, stagnant water, too dry, wrong variety)
  • Soils are degenerated and poor, lacking organic material (humus).
  • Too little diversity and too few shading trees.
  • Not following the correct succession of the forest system, the trees are too old or the wrong variety.
  • Varieties too close together, which have an identical status in the system.
  • Failure to trim the shading trees (too much shade).

 

Examples of Coffee Diseases and Organic Control Methods

Contacts

•    Coffee Research Foundation, P.O.Box 4, 00232 Ruiru, Kenya Tel: +254: (20) 2176420, 2176427, 0733 333 060/ 0724 527 611. Email: director.cri@kalro.org
•    Dormans Coffee. Area of Operation: Kenya. Website: https://www.dormanscoffee.com/
•    Kenya Co-operative Coffee Exporters Ltd (KCCE).Kenya. Coffee value addition. Website: https://www.kencaffee.coop/
•    Uganda Coffee Development Authority (UCDA). Uganda. Website: https://ugandacoffee.go.ug/
•    Rwanda Farmers Coffee Company (RFCC). Rwanda. Website: https://www.jobinrwanda.com/employer/rwanda-farmers-coffee-company-ltd-rfcc
•    Tanzania Coffee Board (TCB). Area of Operation: Tanzania. Website: https://trade.tanzania.go.tz/Contacts/20?l=en
•    Burundi Coffee Board (JAB). Burundi. Website: http://www.jab.bi/
•    Cameroon Coffee and Cocoa Interprofessional Council (CICC). Area of Operation: Cameroon. Website: https://cicc.cm/en/a-propos/

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