Figure 27. Crop leaf ratio - balanced (top) unbalanced (bottom)
Arabica coffee should be grown as a single stem system. Pruning is required to:
maintain good tree shape.
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Year 1 |
Desucker to maintain a single stem system and avoid competition from suckers (Figure 28). |
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Remove 'fly crop' fruit (early fruit which compete with strong plant/root development) as they appear. |
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Year 2 |
Desucker to remove drooping primary branches that touch the ground. Cut back to nearest secondary branch. |
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Remove secondary branches within 8 inches (20 cm) of the main stem. |
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Remove all fruit as they appear (fly crop). |
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Year 3 |
Trees should be allowed to crop in the third year. |
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Cap the main stem by cutting above a side primary shoot at about 5 ft (1.6 m) from soil level. |
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Desucker to remove drooping primary branches touching the ground. Cut back to nearest secondary branch. |
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Remove secondary branches within 8 inches (20 cm) of the main stem. |
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Maintain a maximum number of well-spaced secondary branches on each primary branch. |
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Remove all dead, weak and spindly pest or disease damaged branches. |
As plants grow, they can become too crowded and suffer loss of production. Alternate trees can be stumped by cutting off at knee height - about 20 inches (50 cm) from soil level. When these trees are producing again after two years, stump the remaining trees (see notes on stumping).
Figure 28. General pruning and desuckering of tree over years 1 and 2. Capping during year 3. Newly capped tree photo (above)
A regular rejuvenation pruning is needed (normally at six to seven years depending on tree vigour and yield pattern), to maintain a source of new fruiting wood. Unless trees are renewed, yield will decline over the following years.
Two rejuvenation methods are used:
Full stumping
Side pruning
This involves removing one side of the tree, training a new sucker and then removing the other side of tree two years later. This method is recommended for all growers, as only 50% of the crop is lost for the two-year period.
Two years before stumping, remove all branches on the eastern side of tree after harvesting. Select a new sucker approximately 12 to 18 inches (30 to 45 cm) from the soil level, and train the shoot by thinning as described for a new planting (Stages 1 and 2) until bearing a crop (Stage 3).
Two years later, stump the older stem above the new stem. Cut at a 45° angle - do not cut straight (Stage 4). See Figures 29a, 29b.
Figure 29b. A coffee tree after being side pruned
Figure 29a. The four stages in side pruning a coffee tree
Figure 30. Diagram of full stumping procedure. Choose the strongest shoot and remove the rest; note the 45° cut angle. Photograph of a stumped tree after re-growth (left)
Full stumping
Full stumping involves cutting the tree back to knee height - about 20 inches (50 cm) from soil level, and developing a new stem from the stump (Figure 30). This is not recommended, as the crop will be lost for one and most often two years.
Where possible, supplementary irrigation in the dry season will help maintain plant health and maximize yield potential. Coffee has a water requirement of about 1 inch (20 to 25 mm) per week, which must be supplied from either rain or supplementary irrigation. The amount of water required per hectare for irrigation is about a third to a half less if supplied by drip or under-tree micro-irrigation to the area covered by the plant leaf canopy. Remember that coffee needs to be water-stressed for about four to eight weeks before flowering to give a strong uniform flowering. Do not water trees during this period.
Inter-planting young, non-bearing coffee with vegetables, annual food and cash crops, partly compensates for the high investment cost of coffee establishment, reduces soil temperature, smothers weed growth and supplies the soil with additional nitrogen (legumes) and organic matter when crop residues are turned back into the soil.
Food and cash crops suitable for intercropping include cabbage, peanut, rice, mung bean, vegetables, green beans, maize, upland rice, pigeon peas and pineapple (Figure 31). Keep a distance of 24 inches (60 cm) between the coffee and the intercrop to avoid nutrient and water competition. In some instances with coffee at lower altitudes, pepper vines may be trained up some of the shade trees. Various fruit trees such as durian, guava, lychee, cinnamon (Cassia spp.), avocado, low chill stonefruit, citrus and macadamia are sometimes substituted for legume trees. These of course, should be chosen to suit the altitude.
Figure 31. Young coffee trees with an intercrop of lettuce (top photograph). Pepper vines used as an intercrop on established Erythrina shade trees (middle photograph) with small coffee trees in the centre of the photograph.
Mature, bearing coffee does not allow room for intercropping (bottom photograph)
