Chapter 5
Pruning and tree management

Pruning

Arabica coffee should be grown as a single stem system. Pruning is required to:

• supply good healthy wood for the next season's crop;

• maintain the correct balance between leaf area and crop (Figure 27);

• prevent overbearing and dieback;

• reduce biennial bearing;

• maintain good tree shape.

Figure 27. Crop leaf ratio - balanced (top) unbalanced (bottom)

Desuckering

As plants grow, they can become too crowded and suffer loss of production. Alternative trees can be stumped by cutting off at knee height (0.5 m 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. Decapping during year 3. Newly capped tree (right)

Figure 29a. The four stages in side pruning a coffee tree

Rejuvenation (Change of cropping cycle)

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:

• Side pruning

• 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 300 to 450 mm 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).

Figure 29b. A coffee tree after being side

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.

Full stumping

Full stumping involves cutting the tree back to knee height (500 mm 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.

Figure 30. Diagram of full stumping procedure. Choose the strongest shoot and remove the rest. Photograph of a stumped tree after re-growth (right)

Irrigation

Where possible, supplementary irrigation in the dry season will help maintain plant health and maximize yield potential. In Lao, coffee has a water requirement of about 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.

Intercropping in young coffee

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 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.

In Bolovens Palteaux, various fruit trees such as durian, guava, lychee and macadamia are sometimes substituted for legume trees. These of course should be chosen to suit the altitude.

Figure 31. Intercrop of cabbage (top). Mature, bearing coffee does not allow, room for intercropping (bottom photo)