The macadamia nut tree goes back to Australia and it was introduced in Kenya between 1945 to 1948. In Kenya, macadamia grows in the same climate suitable for growing coffee. The macadamia nut trees remained almost totally unknown in Kenya until after independence in 1964 when a Kenya farming family, Bob Harries and Peter Harries started multiplying the trees in a seedling nursery, planting them on their farms and selling some to other interested farmers.
In 1969 -1971 Bob Harries Limited, a company founded by the late Robert Harries initiated a campaign to sensitize the Kenyan Government to commercialize macadamia nut growing and establish processing and marketing the edible nuts. The Kenya Nut Company Limited was formed in 1974. This company was appointed by the Kenya Government to spearhead and invest in the development of the macadamia nut industry in Kenya.
The tree thrives best at 0-2000m attitude and grows to 9-20m a height and 45 cm diameter (dbh-diameter at breast height). The tree also grows best in areas with mean annual temperature of 15-29 Deg C. and mean annual rainfall of 700-2600 mm. It also requires well-drained soil which is fertile red loams or alluvia derived largely from basic igneous rock such as basalt with a pH of 5.5 to 6.5. Macadamia trees also doesn’t tolerate water and soil with high salt concentrations. They are well-drained loams and sandy loams with good organic matter content.
Varieties of Macadamia Grown in Kenya
The most popular varieties grown in Kenya are Macadamia integrifolia and Macadamia tetraphylla. The Macadamia tetraphylla is more adaptive to cooler climate and has rough-shelled bush nut while the Macadamia integrifolia has smooth nut surface and is adaptive to diverse agro-climatic conditions. In Kenya the two species grafts are used to produce a more improved variety which is now very marketable and in high demand. Macadamia Integrifolia is highly dominant in the commercial clonal production area. Hybridisation occurs freely between Macadamia intergrifoila and Macadamia tetraphylla.
In Kenya the bulk of selections being currently grown is from such hybrids such as KIAMBU 3, KIAMBU 9 and 5, MURANGA 12 and 20, KIRINYAGA 1 and EMBU 1. More selections are being developed from the research programs in K.A.R.LO. Thika. In Kenya, it grows in high potential areas of Eastern, Central and Rift valley provinces.
Macadamias are easily grown from seed, but the seedlings may take 8 to 12 years to bear a crop and the quality of the nuts is unpredictable. The wood of macadamia is hard, thus, requiring
the propagator to have experience to make it successfully. It’s important to note that seeds of Macadamia tetraphylla are collected and seedlings raised from them since it’s recommended as a rootstock due to its resistant to different rootstock diseases. The best seeds for propagation are mature seeds which are not more than 4 months old. The best pretreatment is nicking or soaking in cold water overnight before sowing in a seedbed or in pots/polythene tubes. If sown in a seed bed then transplant the sprouted seedlings from the seedbed to polythene bags when they are 2 cm in height. These seedlings are good as rootstocks if one is to graft. Grafting is the only option to obtain good varieties of fruit in a short period. The rootstock to be used for grafting should be usually seedlings of 9-12 months old with at least a diameter of 1-1.3 cm. The scion wood is girdled (remove a narrow section of bark on about 80% of the circumference of the twig) about 6 to 8 weeks before grating to promote accumulation of carbohydrates. The recommended graft method is a top-wedge grafting or chip budding. Softwood cutting and air-layering is also possible as propagation method. The scion wood can be either, but M. integrifolia is preferred for the best nuts production while the recommended rootstock is M. tetraphylla for its resistant to diseases. It’s important to note that M. tetraphylla is resistant to both macadamia trunk canker and anthracnose, grafting cultivars of M. integrifoila onto root-stock of M. tetraphylla minimizes these problems.
The grafted seedling takes 3-4 months to be ready for planting out in the farm. Seedlings are planting out in the field at a spacing of 9m x 9m or 10 m x 10 m or more if the trees are intercropped with coffee or any other crop e.g. maize; however if they are been planted as pure orchard, the spacing should be 4m x 10 m or 5 m x 10 m.
Production of Macadamia in Kenya
Macadamia is pollinated by insects, as most cultivars are at least partly self-incompatible, planting pollinator trees and introducing bees are both important for good fruit set. After flowering the nuts takes about 6-8 months to mature. Some grafted varieties of macadamias begin bearing within 2 years-3 years.
A young tree raised from a seedling without grafting takes at least 7 years to fruit, while the grafted trees takes 2-3 years to start bearing fruits. The nuts turn brown when mature and one harvest by shaking the tree branches where by all mature fruits or nuts fall down. Sort out the mature nuts from the few immature which may fall down. One can also pick from the tree.
A good tree can yield 45-90 kg nuts on average per year. Harvesting is usually by manual collection of the nuts from the ground or Picking from the crown-picking the fruits which have cracked or turned brown. The husks are removed and the nuts are dried within 24 hours of harvest. Failure to do so initiates undesirable physiological activity which causes fermentation and spoilage. For the production of edible nuts it is important to dry the nuts from an initial moisture content of 45% to between 5% – 1.5%.
Market analysis of macadamia nuts in Kenya
The Kenya macadamia nut industry is currently made of approximately 2 million trees of varying ages from one year to 20 years, grown by over 200,000 small scale farmers with an
average of 6 -12 trees per grower. Annual production is about 10,000 metric tons of nuts-in-shell. These produce about 4000 metric tons of marketable kernels, making the main commercial product. Other by products such as oil, are minimal. Producers get from nuts-in-shell Shillings 1 billion per year.
Kenya is the third largest macadamia producer and the second largest exporter of macadamias. Many Kenyan farmers are integrating macadamia trees into their coffee and tea plantations. They view macadamia output as insurance against the uncertainties of weather which affect coffee and tea. Japan and the United States are the 2 largest markets, together accounting for almost 84 percent of Kenya’s total exports Macadamia.
Nutritional Value of Kenyan Macadamia nuts
It has tough thick shell which encloses a cream-colored oil-rich nut. The macadamia nuts are rich in oil (60-72%), Proteins and Carbohydrates. It is also a good source of Vitamin B1, B2, E, Fibre, Calcium, Phosphorous, Magnesium, Iron, Potassium and Niacin. The nuts can be eaten raw or used to make edible oils or confectionery or baking Macadamia is a good source of calcium. phosphorus, iron, vitamins B and niacin.
Economic importance of Macadamia nuts
The importance of macadamia nut as a tree for inclusion inagro-forestry products lies in the fact that the tree can be interplanted with other cash crops and once established, it needs minimal care in comparison to other tropical tree crops such as the cashew nuts which is confined to the coastal region only.
The macadamia tree has a wider ecological suitability. The main uses for macadamia nut still remain as the kernel which is eaten as a dessert nut, in raw or roasted form, but also for making confectionery products. Soaps and cosmetics industries use the oil as a raw material. The oil press cake can be used as a livestock feed additive, the shells can be used to make charcoal while the wood also has the potential for production of hard timbers for the furniture or building.
- Apiculture: Macadamia pollen is very attractive to bees, providing necessary forage for honey production.
- Fuel:Macadamia shells may be used as fuel, generating sufficient energy to dry wet, in-shell nuts.
- Tannin or dyestuff: The hulls, the green covering of the nuts, contain approximately 14% of substances suitable for tanning leather.
- Lipids: Macadamia is the richest oil-yielding nut known. The kernel contains more than 75% oil, suitable for human consumption.
- Essential oil: The characteristic, subtle macadamia flavour is probably due to volatile compounds, the major ones being similar to those in other roasted nuts Services
- Shade or shelter: M. integrifolia/ tetraphylla makes an excellent evergreen shade and shelter due to its thick crown of leaves.
- Soil improver: The decomposed husk is commonly used in potting soil.
- Ornamental: As well as being an evergreen nut-bearing tree, M. integrifolia/ tetraphylla has good symmetrical shape and when in full bloom is covered with creamy-white and pinkish flowers. These make it a popular ornamental tree.
- Intercropping: Inter-row cropping can be practised with trees such as citrus or coffee or maize.
- Health aspect: Macadamia fats helps lower cholesterol and Improves blood circulation they provide antioxidants that prevent arteriosclosis
Way forward for Macadamia nuts Farming in Kenya
- The most effective grafting method need to be researched on, to increase the production of grafted or high quality seedlings
- Continued work needs to be done in cultivation practices and methods of propagation.
For any question regarding macadamia farming in Kenya, give us a call or pay us a visit. In addition, do your own research and compare notes, this is just to help you.