The area to be planted with coffee must be prepared at least one year before the small coffee trees are planted out. There are five procedures to follow.
Prepare the land.
Plant windbreaks.
Mark out the rows.
Establish shade trees.
Irrigation.
The land must be cleared and all old trees and their roots removed - do not leave old timber lying around as this attracts pests. With land up to 15% slope, run the rows across the slope making sure there is a fall of 1 to 2% for drainage. Ground covers should be planted to avoid erosion. When land is greater than 15% slope, contour planting must be undertaken.
Establishing a contour strip
Coffee is planted in rows 2 m apart with plants 1.5 m apart within the row. To mark the planting holes at this spacing on sloping land, follow the steps below.
Construct a simple wooden A-frame structure measuring 1.5 m high with legs 1.5 m apart. The horizontal support cross-piece is marked at the central point. A string with a weight (stone or metal object) is attached at the apex of the ‘A' and allowed to hang freely, similar to a pendulum (Figure 15).
Starting at the bottom of the slope, 'walk' the A-frame across the slope by rotating it from one leg of the frame to the other. Place a marker at each point on the ground where the pendulum lines up with the centre mark on the A-Frame cross-piece. This marker shows the planting hole for each plant on that particular row/contour. Continue for the desired length of the contour line.
Locate the next contour line 2 m up or down hill from the first row. Follow the same marking procedure until the entire field is marked out.
Figure 15. Constructing an A-frame (top). Using an A-frame to find the contours in a field and marking the planting holes
In general, permanently planted windbreaks are only recommended in sites exposed to strong winds, and then only where they are needed to supplement inadequate natural forest surrounds. If required, windbreaks should be well established before planting out the coffee trees. Windbreaks are usually located along boundaries of the coffee area. Silver Oak (Grevillea robusta) is a preferred windbreak tree.
Mark out the rows
Row direction. Ideally a north/south direction is best as it makes most use of sunlight. Mark out where the rows are to go.
Shade trees need to be well established before coffee trees are planted out. Plant shade trees one year before planting coffee. Do not plant shade trees at the same time or after planting the coffee seedlings.
Shade protects young coffee plants from drought stress and over exposure to sun, which causes yellowing and death of leaves, tree overbearing and/or dieback in older trees. Shade also promotes a better balance between flowering and growth resulting in better berry production. Legumes used as shade trees contribute substantially to soil health by providing organic matter and nutrients from leaf fall and prunings, and fix nitrogen from the air to restore soil fertility and structure. Shade trees also reduce the incidence of frost.
Figure 16a. Erythrina shade trees
Figure 16b. Melia shade trees
Numerous species can be used as shade trees - the preferred types include:
Erythrina subumbrans (Tton Tong or Dadap). Used as coffee shade and for pepper supports in many areas of S-SE Asia. It is fast growing and easily propagated from cuttings (Figure 16a).
Gliricidia sepium (Khae Falang). Looses leaves and begins to flower in the dry season unless pruned in wet season to keep plant vegetative. Fixes nitrogen from the air.
Cassia siamea(Khi Lek). Does not fix nitrogen and can compete with coffee for nutrients and water.
Melia azedarach (Khao Dao Sang, Neem or Bead tree). A good timber tree that may provide some insect control. Seed extracts are used as the insecticide Neem (Figure 16b).
Paulownia tomentosa. A quick growing, timber tree.
Shade tree spacing
Figure 17. Ideal size of transplant tree
Suggested spacing for Erythrina, Gliricidia, and Cassia is 4.5 x 4 m (555 trees/ha), while that of Melia and Paulownia is 6 x 6 m (277 trees/ha).
Plant shade trees within the coffee rows. Remove lower limbs from young shade trees as they grow.
If irrigation is to be used, it should be installed prior to planting of coffee trees. If there is no irrigation, both shade trees and coffee will need hand watering for a few weeks until established.
There are four procedures to follow when planting the coffee trees.
When to plant (seedling size and time).
Prepare the holes.
Choose the plants.
Planting procedure.
Figure 18. Procedure to follow when preparing the holes: 2 to 3 (top); 4 to 6 (bottom)
Field planting can begin when the coffee plants in bags have a minimum of six to eight leaf pairs (Figure 17). Plants should be strong and healthy with no sign of pests or disease. Planting out in the field should be done on cloudy days, in June through to August during the wet season. Avoid planting trees when conditions are windy or hot and dry or during the hottest part of the day.
One month before planting
1 Mark the planting holes.
2 Dig holes of 600 x 600 x 600 mm (Figure 18).
3 Pile topsoil to one side of the hole, subsoil to other side of hole.
4 Mix in 2 kg of dry farmyard manure (FYM) + 3 heaped soupspoons (about 85 g) Triple Superphosphate (TSP).
5 Mix into loose soil at the bottom of the hole and into the pile of topsoil.
6 Start filling the hole with topsoil only. Then use both the subsoil and topsoil to complete filling the hole.
7 Re-mark the centre of the hole with a stick.
At planting
Spread 1 milk tin (225 g) of dolomite over the soil in the planting hole and then dig in.
The soil should be moist at time of planting.
Figure 19. Unsuitable plant with a twisted root system
Check that the coffee plants:
are healthy, with dark green, well-formed foliage and a minimum of 6 to 8 leaves;
have no stem damage and a well-developed root system with a taproot that is not distorted. (Figure 19);
are not root-bound by being in the pots for too long and have been hardened to full sun before planting.
Figure 20. Planting procedure - planting, mulching, ground covers
1. Before planting, thoroughly water the trees in the bags.
2. Remove plants from plastic bags by either cutting the bag or gently sliding the plant out of the bag.
3. Discard plants with J-roots or bent roots (Figure 19).
4. If plants have been in the bags for an extended time, roots may grow around in a circle inside the bag. It is important that these roots are gently teased out by hand or they will continue to grow in a circular manner when planted. Carefully straighten large roots and prune off badly twisted roots.
5. Be sure to remove the plastic bag! Do not plant coffee plants still in the plastic bag.
6. Place the seedling upright in the hole - do not plant at an angle. Half-fill the hole with soil, gently pressing the soil into contact with the root ball. Fill hole with water. This helps to bring the soil into close contact with the roots. Allow water to drain, then finish filling the hole with soil (Figure 20).
7. Firmly press soil down with your feet. Do not stomp on the soil as this may damage the young roots. Keep the final soil level slightly heaped above the surrounding undisturbed soil as the soil will settle down after planting. Do not plant coffee in large depressions, as these will trap water. Coffee does not like wet soil and plants can die under these conditions.
8. Water in the plants well, with 1 to 2 L of water per plant.
9. To maintain soil moisture and control weeds, mulch the newly planted coffee trees with rice straw or other suitable materials. Keep mulch away from the base of the plant to reduce the risk of disease. It is especially important to re-mulch at end of wet season.
10. Pigeon pea, sorghum or other crops can provide temporary shade cover for young plants.
11. Blady grass (Imperata cylindrica) covers can be used for frost protection.
12. Legume ground covers of pinto peanut (Arachis pintoi) or green leaf desmodium (Desmodium intortum), will greatly assist with weed control in young coffee. Ground covers add nitrogen to the soil, provide mulch for the shade trees and feed for cattle that are a popular source of alternate income on the Bolovens Plateaux. Prunings from legume shade trees are also a good protein food supplement for cattle.
To achieve high yields of quality coffee, good field management practices are essential. Poorly managed coffee will take longer to produce a good crop and will suffer from dieback. There are three key procedures to follow:
Protect from frost;
Control weeds and mulch plants;
Water plants.
(Nutrition and fertilising are fully covered in the next chapter).
Good site location and use of shade trees will reduce the incidence of frost. Maintaining soil moisture during frost periods will offer a degree of frost protection.
Figure 21. Newly planted coffee trees with frost protection in place
Plant covers like blady grass (Imperata cylindrica) to protect young plants from frost (Figure 21). In cold weather, overhead irrigation applied before ice starts to form, will prevent major frost damage. Continue watering until temperature has warmed to above freezing and ice melts.
Keeping the ground free of weeds and ground covers cut short in the frosty period will also help with frost protection (Figure 22). Severe frost may kill small trees. However, on most occasions (especially with larger trees), the tree branches die back and then regrow, but one to two seasons will be lost before complete recovery.
Figure 22. Frost damaged trees in the field (above) and close-up of frost damaged leaves
Coffee trees are shallow-rooted, which means that most feeder roots are near the surface. Weeds compete for both nutrients and water, so it is essential to keep the area under the canopy of the trees, weed-free.
Coffee plants should be mulched with rice straw or other appropriate material to a depth of 50 to 80 mm especially at the end of the wet season, but be sure to keep mulch materials 50 to 100 mm away from the trunk of the tree.
Mulching will reduce the amount of weeding required. Weeding should be done at least four times per year, especially in the wet season, during which two or three weedings may be needed. When weeding, be careful not to damage surface roots of the coffee plant with knife or hoe.
Dead or dry weeds can be used as mulch. Fresh weeds may regrow, especially in wet weather if they are not dried properly before being added as a mulch.
Do not allow the plant root ball to dry out after planting. Irrigate (or hand water where irrigation is not installed), two to three times per week for the first few weeks. If planting at the recommended time (June to August) there should be a good chance of rain, so the soil moisture should be maintained.
