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Best practices for cashew nuts planting
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Farmer checks for pests on his cashew nuts. Photo | File
What you need to know:
- Cashew nuts are usually propagated through seed or grafted seedlings. Using direct seeds, they are planted in the planting hole and two months after germination occurs.
Cashew nut is scientifically known as Anacardium occidentale and is believed to have originated from South America.
Experts say the Portuguese introduced cashew nut to Mozambique where it flourished forming extensive forests; eventually spreading to the East African region.
In Africa the crop has spread for more than 500 years either naturally or through smallholder cultivation.
Experts from Kenya Agricultural and Livestock Research Organisation in a guide prepared for farmers growing cashew nut, note that it is important for East Africa including Uganda to adopt cashew nut growing because the plant rich in food value and good for human health.
Background
Experts contend cashew nut can be grown in any part of the country but it is mainly farmers in northern and eastern Uganda who are growing it most. A number of initiatives have been ongoing to revamp cashew growing with the National Agricultural Forestry Resources Research Institute (NaFORRI) taking lead.
Dr Francis Esegu, the former director of NaFORRI in a previous interview with Seeds of Gold noted that cashew nut tress species was introduced in Uganda from Brazil in 1960s and it grows well in the cattle corridor areas such as Karamoja that are semi-arid.
But due to civil strife and insecurity in these regions the trees have suffered neglect. In 2010 the researchers decided to revamp the growing of cashew nut by undertaking research to come up with disease free varieties.
The researchers in collaboration with development partners such as Common Fund for Commodities came up with a project in a bid to revive production of the trees.
The ministry of agriculture has also come up with an initiative of revamping cashew nut growing by ensuring seedlings are multiplied and given to farmers.
But for this to yield success, farmers need to know about the best practices in order to reap big and below are the best practices to be adopted.
Scientists from KALRO namely Francis K. Muniu, Stella Mwashumbe and Pole Finyange, Christine Kasichana and John Ndungu state that the crop has a number of uses from its nut which can be roasted and the oil can also be extracted and used as medicine.
Ecological requirements
Cashew nut does well in tropical climate with high and constant temperatures. It can be grown in elevations of between 0 and 1,000 metres above sea level with an ideal elevation of 600 meters above sea level.
The trees do not tolerate low temperatures as this interfere with reproductive cycle of the tree and leads to delayed flowering and poor yields.
Temperature
Rainfall should be between 500mm to 1200mm per year. Dry weather is required for the cashew nut plant to flower. A period of at least 4 to 5 months of dry weather after the rains is required for optimal yields.
Excessive humidity leads to emergence of many fungal diseases for the cashew nut plant. It requires well-drained and light textured soil.
Heavy clay (including dark cracking clays), compact and hard surface setting soils hardpans or with concretions within rooting zones are not suitable for cashew nut product.
Varieties
Recommended varieties of cashew nut are A75/83, A100, A81 and A82. Cashew nut can either be propagated by seeds or grafted seedlings.
Propagation
Cashew nuts are usually propagated through seed or grafted seedlings. Using direct seeds, they are planted in the planting hole and two months after germination occurs the weak.
Propagation using grafted seedling starts by raising rootstock propagated from local cashew nut varieties.
Farmers are expected to carry out visual selection of seeds to remove diseased or deformed seeds.
The selected seeds are taken through flotation test in water. Seeds that sink are planted in peregrination beds.
The pre-germinated seeds are transplanted into potting bags when the tap root are 2.5–3cm after 7-10 days.
The seedlings are transplanted in potting bags. This composition is able to sustain the plant for averagely three months after transplanting the pre-germinated seeds in them.
Seedlings are ready for grafting when they attain more than two functional leaves and the cotyledons are still attached to the young stem.
Grafting is done 3-4 weeks after transplanting into potting bags. Scions for grafting are harvested from select mother plants. The seedlings of cashew nut are grown under shade of 60 percent and hardened off before planting in the orchard. It is very important not to disturb the root system during planting. Young trees should be supported with a stick for the first 2 to 3 years so that the wind will not blow the plants over.
Planting
Cashew nut should be planted at the beginning of the rain season. The best time for planting will depend on available soil moisture. The best time for planting is at the onset of the rains.
To establish a cashew nut orchard, farmers are expected to plough the land thoroughly, removing stems and roots. Lay out the field by spacing holes 12m x 12m. A spacing of 6m by 6m can be adopted with intention of thinning to 12m by 12m at a later stage when the canopies start to overlap.
Mix the top soil with two buckets of well decomposed farmyard manure and 150g about 7.5 table spoonful of DAP. Carefully remove potting bag without disturbing the roots and plant at the centre of the hole.
Plant the cashew nut seedling at the same soil level as that of the soil when the seedling was in the potting bag to avoid burying the graft union.
Prepare a shallow basin and cover with mulch and water after planting. Water regularly and intercrop with short duration perennials such as papaya, maize, cassava, cowpeas, tomatoes, melons, pumpkins, chilies, egg plants and ensure that the orchard is always free from all kinds of weeds.
Managements of the orchard
Formative pruning is the training done on the grafted plants to make the tree grow upright to a height of 1.0-1.5 m. This work should be done within the first 5 years after establishment of the cashew nut tree and is important for continuous development of the tree. To avoid the risk of fire in the field, it is necessary to put fire breaks around the field soon after planting particularly during the dry season.
Young cashew nut seedlings are susceptible to damages caused by diseases and pests. It is important that the seedlings are routinely scout the seedlings and take preventative measures.
Irrigation is important during establishment of young trees because it doubles the growth tempo of young trees in a dry season.
Due to the deep root system the trees can survive several months without irrigation. Mature trees should receive 1,800L of water per tree every two weeks. Grass strips in the inter-rows between the tree lines are ideal to prevent erosion and should be cut regularly. Pollination is mostly carried out by insects and after the process, it takes six weeks for fruits to develop. Concentration of honey bee colonies during flowering would alleviate problem of poor fruit setting
Harvesting and post-harvest handling
Cashew nuts planted using seed begin bearing four years after transplanting the seedlings. The nuts should be harvested as soon as possible, especially under wet conditions and should be dried before storage.
Grafted seedlings begin bearing within two years of transplanting. Depending on age and maturity of plant, a tree yields between 10 and 100 kilogrammes of unshelled nuts per year.
One hectare can thus produce between 2,000 and 5,000 kilogrammes of unshelled nuts per year. Although trees can produce for 40 to 50 years, commercial harvesting is for 35 years. To get good quality nuts, clear the area beneath the tree, collect fallen fruits, detach the nut from the apple and dry the nuts under the sun for about two hours.
Planting
Cashew nut should be planted at the beginning of the rain season. The best time for planting will depend on available soil moisture. The best time for planting is at the onset of the rains.