Techniques for planting and caring for cocoa trees

1- General characteristics and external requirements:

Cocoa trees are suitable for hot, humid, rainy tropical climates. Suitable for an average temperature of 25oC, humidity of 85%, average rainfall of over 1500 mm/year. Cocoa is suitable for a climate with a dry season that does not last more than 3 months, an average temperature of 25oC, and no frequent strong winds.

Cocoa is a tree that loves diffused light (50-60% of natural light intensity), so it is suitable for planting under the canopy of fruit trees or shade trees.

Cocoa trees are suitable for many different types of soil: red soil, gray soil, ancient alluvial soil, but are most suitable for soil with medium to light mechanical composition, pH from 5.5-5.8, a thick arable layer of 1-1.5 m, well-drained, has high water retention capacity, and is rich in organic matter. However, by cultivation methods (liming, organic fertilizers...) can help cocoa trees achieve high productivity on infertile land.

In our country, cocoa is grown in many different ecological regions from the South Central Coast, Central Highlands, Southeast and Mekong Delta. Cocoa is a perennial industrial plant, with a lifespan of more than 30 years. After about 12-14 months of planting, the tree will flower and bear fruit, and in the 18th month, the first harvest will be harvested, after which it will give a stable yield of 3-4 tons/ha. The highest yield can be achieved in the 5th year and maintained for up to 30 years, so cocoa growers must pay attention to investing in good varieties.

The characteristic of cocoa trees is cross-pollination, the heterozygous state in parent trees is very high. Thanks to advances in biotechnology in breeding, it helps to identify suitable parents in crosses as well as test hybrids in the nursery stage to determine the uniformity of hybrids, eliminating unwanted hybrids before planting.

Through many years of monitoring and evaluation, the Tay Nguyen Institute of Agricultural Science and Technology has selected 5 parent trees from 500 seedlings of the local and imported cocoa breed group planted in 1978 and 1980 to provide seeds for production. These parent trees satisfy the main selection criteria such as: Good growth, average yield of 5 crops reaching 3.9 kg of dry beans/tree and medium to high resistance to fruit rot disease (Phytophthora palmivora). These parent trees (TC5, TC7, TC11, TC12 and TC13) were recognized by the Ministry of Agriculture and Rural Development in 2005.

Cocoa planting season: depending on weather and climate conditions, choose the appropriate one, it is best to plant at the beginning of the rainy season. On good soil, the planting density is 3x3m, on poor soil, the planting distance is 3x2.5m. Before planting, prepare a hole measuring 50x50x50cm, when digging the hole, keep the topsoil and deep soil separate. It is best to prepare the planting hole 2 weeks in advance.

2- Cocoa planting techniques:

The land for planting cocoa needs to be selected with a thick arable layer, a deep groundwater level and good drainage, avoiding stagnant water when it rains. Prepare the soil carefully, ensuring the soil is loose.

After digging holes according to the required density, each hole needs to be fertilized with 10-15 kg of decomposed manure + 0.5 kg of lime powder and 0.5 kg of Dau Trau phosphate fertilizer, combined with termite treatment with Confidor or Admire at a concentration of 0.1-0.2%, sprayed evenly under the hole and on the sides of the hole a few days before planting.

When planting cocoa, dig up the soil in the middle of the hole, place the pot and use a sharp knife to cut the pot, avoiding breaking the pot. Cocoa is a plant that cannot tolerate stagnant water, so when planting, the pot surface must be placed level with the ground. In the natural conditions of the Mekong Delta, cocoa is very suitable for intercropping in coconut gardens and fruit gardens because it can take advantage of scattered light and limit ecological limitations such as long droughts, floods, high water levels, and thin cultivation layers.

If cocoa is grown purely, it is necessary to plant shade trees or make a trellis, especially in the first year of planting and the basic construction stage. During this stage, cocoa trees need 50-75% shade trees for the trees to grow and develop well. After planting, it is necessary to water regularly to keep the soil moist and avoid stagnant water causing waterlogging. After 1 month of planting, it is necessary to spray termite control medicine for the second time with Confidor or Admire. The medicine should be sprayed around the hole and the entire tree.

3- Fertilizing cocoa trees:

3.1- Nutritional needs of cocoa trees:

Cocoa trees absorb a lot of nutrients, of which potassium is the highest. 1 ton of cocoa beans in western Malaysia takes 31kg N + 11.2kg P2O5 + 64.8kg K2O + 8kg CaO + 6.8kg MgO. In addition to macronutrients, cocoa has a fairly high demand for medium and micronutrients. The nutritional needs of cocoa increase with the age of the tree and the level of productivity. Early-harvested cocoa has higher nutritional needs than basic construction trees and trees in the nursery. Commercial cocoa has higher nutritional needs than newly harvested cocoa (Table 1).

Table 1: Nutrients absorbed and taken by cocoa trees (1100 trees/ha)

3.2- Symptoms of nutritional deficiencies in cocoa trees

- Nitrogen deficiency: leaves are yellow-green or banana green. Severe deficiency causes many leaves to fall off, reducing productivity. Nitrogen deficiency often occurs on poor soil and insufficient nitrogen fertilization.

- Phosphorus deficiency: leaves turn dull, young leaf edges turn red, severe deficiency causes leaves to fall off and branches to die.

- Potassium deficiency: Leaf edges turn orange-yellow to gray-brown and dry, many leaves fall off.

- Magnesium deficiency: leaf flesh turns yellow and gradually spreads from the main vein to the leaf edge.

- Calcium deficiency: leaves turn yellow from the leaf edge to the main vein.

- Zinc deficiency: leaves and shoots at the top of branches do not develop well (shrinking shoots), leaves cannot expand. Zinc deficiency is also quite common in famous cocoa regions of the world.

Table 2: Nutritional diagnosis through cocoa leaves

3.3- Fertilization process for cocoa trees:

Cocoa trees need to be provided with sufficient macro, medium and micro elements. Lack or excess of any of these elements will affect the abnormal growth and development of the tree. Fertilizer needs of cocoa depend on the age of the tree and productivity. Commercial cocoa needs more fertilizer than basic construction cocoa. The higher the cocoa productivity, the more fertilizer is needed.

* Fertilizing cocoa in the nursery:

- Apply 2 kg of organic fertilizer + 0.5 kg of Dau Trau compomix for each m2 of nursery bed or 0.2 m3 of soil to make a soil ball before sowing. - Apply top dressing by dissolving 20-30 grams of NPK-20-20-15+TE Dau Trau fertilizer in 10 liters of water, watering periodically 2-3 weeks/time. Spray Dau Trau 007 foliar fertilizer periodically every 7-10 days/time.

* Fertilizing basic construction cocoa:

- Apply 10-15kg of organic fertilizer and 0.3-0.5kg of Dau Trau phosphate to each planting hole 10-15 days before planting.

- Top dressing: Basic construction cocoa needs a lot of nitrogen, phosphorus, a little potassium and micronutrients for the tree to develop roots, stems and leaves. Fertilizer for cocoa trees in the basic construction stage is NPK-20-20-15+TE or 16-16-8+TE Dau Trau, the amount of fertilizer depends on the age of the tree as follows:

First year: 0.2-0.3kg/tree.

Second year: 0.5-0.6kg/tree

Third year: 0.6-0.8kg/tree.

This amount of fertilizer is divided into 4 times at the beginning, middle and end of the rainy season and once in the dry season. Basic cocoa tree construction, each tree only leaves 1-2 main trunks and cuts off excess branches, weak branches, and removes shoots below the grafted eyes for cocoa gardens grown with grafted trees. For commercial cocoa trees, excess branches and drooping branches should be pruned, and weak branches, dry branches, and diseased branches should be cut off 3 times a year.

* Fertilizing cocoa trees for commercial purposes:

Cocoa for commercial purposes has the highest demand for potassium, nitrogen, phosphorus and micronutrients. In Malaysia, the most commonly used fertilizers for commercial cocoa are NPK-12-12-17, NPK-15-15-6-4, NPK-10-10-15.

In our country, cocoa is mainly grown in the Mekong Delta, the Central Highlands and the Central region, so the most suitable fertilizer for commercial cocoa in these areas is “Dau Trau Ca Cao” fertilizer. This is Dau Trau fertilizer specifically for cocoa with the content of: 12% N, 14% P2O5, 18% K2O and suitable micronutrients; especially supplemented with Penac P from Germany. The amount of fertilizer varies depending on the soil type, tree age and yield, fertilizing: 1.5-2.5 kg of Dau Trau cocoa per tree/year, the above amount of fertilizer is divided into 3 times at the beginning, middle and end of the rainy season. Due to the characteristics of the shallow root system of cocoa trees (80% of the roots are concentrated in the 0-30cm layer), it is necessary to fertilize in the topsoil. Spread fertilizer along the canopy and then bury it to reduce loss due to evaporation and leaching. During the commercial period, the trees have a canopy, can withstand drought and give quite a yield. However, in the Central Highlands, Central and Southeast regions, when watered 1-2 times a year, cocoa trees grow and give much higher yields.

4- Prevention of pests and diseases of cocoa:

Cocoa trees have a number of dangerous pests and diseases that affect the growth, yield and quality of cocoa beans.

* Pests:

Common pests found in cocoa gardens are mainly concentrated in the group of sucking insects belonging to the two orders Homoptera and Hemiptera, this is the main group of pests that cause damage to all growth stages of the tree.

- Worms eat cocoa leaves mainly at night, during the day they hide at the base of the tree or move to another place. Among them, there are species that eat leaves very strongly, causing cocoa gardens to be bare and bare, pests often attack cocoa gardens in the new planting year and the basic construction stage.

To prevent, when there are many pests on the leaves, spray pesticides such as: Sherpa 25ND, Supracide 40EC, Polytrin 440ND at a concentration of 0.2 - 0.3%.

- Mosquito bugs (Helopeltis spp) often bite young shoots or young leaves, causing black spots, young leaves will be deformed and then dry up. Large fruits that are bitten by mosquito bugs will crack the shell and then rot; Young ripe fruit is often darkened and dried.

Prevention: When the density of stink bugs is high, spray pesticides in the early morning or late afternoon with Subatox 75EC, Polytrin 440ND at a concentration of 0.2-0.3%.

- Aphids mainly damage young leaves, young shoots, young fruits, flower clusters... When young leaves are sucked, they will curl up, damaged flower clusters will not develop, if the fruit is ripe, it will develop abnormally, and the fruit will have few seeds.

Prevention: Cutting off excess shoots is ineffective in limiting the habitat of aphids. If the density is high, spray pesticides such as Pyrinex 20EC, Subatox 75EC, Suprathion 40EC at a concentration of 0.2-0.3% to eliminate them.

- Mealybugs (Pseudococus sp.), green cotton aphids (Coccus viridis) often cause damage on fruit stalks, on the surface of fruit peels and on young leaf buds.

Prevention: Timely detection is needed to spray pesticides such as: Selecron 500ND, Supracide 40EC Confidor with a concentration of 0.2-0.3% for prevention. The isolation period from the last spray to fruit harvest is about 3 weeks.

* Diseases:

Dangerous diseases on cocoa trees, in the nursery stage such as:

- Root collar rot (Rhizoctoni sp), leaf rot (Collectotrichum gloesponiodes), stem rot (Phytophthora sp.), crown rot (Fusarium spp, Collectotrichum sp), leaf petiole rot (Rhizoctonia solani).

Prevention measures, early detection of diseased trees, remove from the garden, if the nursery cover is too thick, remove some to ventilate the garden. Do not let the garden get too humid. When the disease is severe, spray Zineb 75% at a concentration of 0.3% and Copper Oxide Chlorur 50% mixed at a concentration of 0.5% to spray or water the diseased trees.

- Stem and branch rot caused by Ceratocystis fimbriata, stem dieback caused by Verticillium dahide, leaf blight caused by Colletotrichum sp, black root rot caused by Rosellinia pepo, and cracked root rot caused by Armillana mellea.

Fruit rot caused by Phytophthora spp: Fruit rot caused by Phytophthora spp, is the most common and serious damage in cocoa growing countries in the world as well as in Vietnam.

The disease causes drying and rotting of fruit at a very high rate, usually from 30-80%, with some trees being severely affected by 100%, the disease damages from when the fruit is young until it is ripe.

Prevention and field sanitation are the first measures that must be taken, especially for gardens that already have a source of the disease. Reduce the humidity in the garden and spray Aliette 80WP with a concentration of 0.2-0.3%, Ridomil with a concentration of 0.3% after the flowers have bloomed, spray every 3-4 weeks until the diameter is over 3mm.

- Virus disease causes leaf curl; the preventive measure is to destroy disease-carrying insects such as stink bugs, whiteflies, aphids... with the above drugs. It is necessary to monitor the garden regularly to detect pests in time to contact the professional agency for identification and timely instructions on prevention and treatment.

5- Cocoa harvesting:

The quality of cocoa beans mainly depends on 3 factors: variety, care techniques and harvesting and preservation methods. When applied correctly, it will create high-quality products that bring high efficiency to cocoa producers.

Here are the harvesting and preservation techniques to achieve high quality beans:

- Only harvest ripe fruits, do not harvest green fruits.

- After harvesting, it must be processed immediately and not left for more than 4 days (use a knife or scissors to cut the fruit stem when harvesting).

- Use a piece of wood to break the shell of the fruit to get the seeds and ferment them.

Currently, in the domestic consumption market, farmers can pre-process and sell them to cocoa processing factories or companies specializing in purchasing for export.

The cocoa processing industry in our country is developing, such as cocoa processing factories in Quang Ngai and Ho Chi Minh City currently do not have enough raw materials, so they have to import cocoa powder and cocoa butter because domestic production is too little to supply the domestic market.

Every year, Vietnamese confectionery and beverage processing factories have to import about 1,000 tons of cocoa powder and a small amount of cocoa butter equivalent to about 2,700 tons of dry cocoa beans. Recently, cocoa prices have been fluctuating, but the lowest price is 700 USD/ton and the highest can be up to 3,000 USD/ton.