Introduction to Macadamia Nuts Farming in India
Macadamia is a tree which is grown for its edible seeds (nuts) is called Macadamia nut. It also referred to as Queensland Nut or Australian Nut and originates from Australia. A Macadamia tree belongs to the genus Macadamia and belongs to the family Proteaceae which are grown for their edible seeds (nuts). The global production of the Macadamia Nut is about 51,900 metric tons. Macadamia nut is cultivated in South Africa, Brazil, California, Israel, Kenya, New Zealand, and Malawi. In India, Macadamia Nut is cultivated in Kerala, Tamil Nadu, Karnataka, and Orissa. Now, let’s get into Macadamia Nuts farming and cultivation practices in India.
A Step by Step Guide to Macadamia Nuts Farming in India
Macadamia trees naturally have multiple stems but are trained to a central leader system (single stem) in plantations. The tree leaves are oval or oblong and are arranged in whorls of 3 or 4 depending on the variety. The Macadamia tree produces creamy white or pink-red flowers on racemes of 100-300 flowers. It covers a single spherical or elliptical seed or nut with a white or gray kernel depending on the variety of trees. Macadamia can reach a height of about 20 meters and have a commercial lifespan of 40 to 60 years.
Macadamia nuts are quickly becoming an important crop. Tree flowers are small and whitish, and growing on long spikes, while their nuts can ripen throughout the year. The nut has a leathery case that is 1 inch in diameter, containing a spherical nut. Also, they have a smooth hard shell that encases a white kernel.
Macadamias are shallow-rooted, so need plenty of water, mainly during dry spells. Mulch to keep the plant roots cool and help prevents the soil from drying out. The fruit of the tree is the most expensive and finest nuts in the world. It grows in moist areas but grows faster in tropical and subtropical areas. The Macadamia tree tolerates the cold up to -5°C. Macadamia tree is easy to grow, can grow on most soils, and can tolerate dryness.
Characteristics of Macadamia Tree;
- An evergreen tree of the Proteaceae family
- Height – up to 20 m., but it does not exceed 12 m.
- Appearance – dense and thick crown, rounded. It is used as an ornamental tree.
- Leaves opposite, petiolate, oblong, glossy, pale green, and wavy with serrated margins.
- Flowers hermaphrodite, white or cream, arranged in pendulous racemes 10 to 20 cm in length.
Different Varieties for Macadamia Nuts Farming
- ‘Dwarf Macadamia’ tree grows to half normal size and it is ideal for pots or limited space.
- ‘Daddow’ is a vigorous, dense, and spreading tree.
- ‘A4’ is a precocious tree that can produce commercial yields in 3 years. It’s a medium-sized tree with an open canopy.
Soil and Climatic Requirements for Macadamia Nuts Farming
Macadamia trees grow on a wide range of free-draining soils but perform best on deep and well-drained soils. For successful commercial Macadamia production, a minimum depth of 0.5 meters of friable, well-drained soil is essential. A depth of 1meter is preferred, as this minimizes the risk from trunk canker disease and tree decline. Though, be aware that extremely well-drained spoils can be a problem in drought years, if not irrigated. Avoid soils with heavy clay or rock bars within 1 meter of the surface. Macadamia nut trees can be grown on deep and well-drained soils with a pH level of 5.0-6.5.
Temperature (especially the average daily and seasonal range of temperature) plays an essential role in the size of crop yield.
Macadamia trees provide good yields in areas with;
- Yearly average temperature levels around 20-25°C.
- The difference between the average daily and nightly temperatures must be at least 8°C.
- Average summer temperature levels around 25-30°C.
- Average winter temperature levels around 20°C.
- For blossoming to commence, the nightly temperature levels must fall below 19°C.
- Frost-free regions are recommended. Frost below -6°C will kill off young trees and destroy the plant leaves and blossoms of older trees. Light frost can be withstood by older trees; sensitivity to frost is similar to avocado, lemons, and oranges.
- During long periods above 40°C, those leaves exposed to solar radiation will burn, and the crop yield will be diminished.
Conditions Required for Macadamia Nuts Farming
- Macadamia nut cultivation is best suited in sub-tropical conditions with high summer and low winter temperature levels.
- Well-drained and sandy loam light soil is preferred with a pH level of 5.0-6.5.
- Macadamia trees originate from the sub-tropical rainforests of Australia and they tend to grow best in areas of high humidity and rainfall.
- Macadamia trees should not be planted in heavy clays.
- Macadamia is a tropical tree and it requires full sun to grow and produce healthy fruits.
- Some Macadamia tree cultivars have an upright growth pattern, whereas other cultivars tend to have more lateral growth. Lower density plantings will still require pruning and optimal crop yield per hectare.
Propagation for Macadamia Nuts Farming
You could propagate Macadamia nuts tree from seeds or cuttings. Either way, it is easy to propagate. Though, propagating it from cuttings is faster than propagating it from seeds. Macadamia seeds will take 10 to 12 years to start producing fruits. However, cutting usually takes 4 to 6 years. There are several varieties of fruiting Macadamia nut trees. But not all varieties produce edible fruits. Macadamia integrifolia and Macadamia tetraphylla are the only 2 varieties of Macadamia fruits you can eat.
Process of Planting in Macadamia Nuts Farming
Step 1) You could buy the seedling of the Macadamia tree from the local nursery store. Make sure to select a seedling of the Macadamia integrifolia variety or the Macadamia tetraphylla variety. Then, drill a hole in the soil as deep as the root balls of the seedling.
Step 2) Propagation on commercial plantations is always by the vegetative way, as otherwise, the variety-characteristics become lost. Then, reducing the risk of passing over diseases is the number one priority in tree nurseries.
Step 3) Macadamia nuts to be used as seeds can be stored for at least one season. Germination of most of the Macadamia nuts takes 3-5 weeks. As soon as the seedlings are 5 cm tall, and have 2 to 3 green leaves, they are transplanted into large, sturdy plastic bags. Only plants with well-developed root systems must be chosen. The 9-12-month-old seedlings, which have a diameter of about 1-1.3 cm, can now be used as rootstocks.
Step 4) The scions are ringed 6 to 8 before they are grafted, by removing a 2.5 cm wide ring from the bark and cambium zone, to introduce more carbohydrates into the scion. The most advantageous times to graft are autumn, and especially in the spring season. The most successful ways are “whip-grafting” and budding. It is difficult to graft due to its hardwood and it is important to use sharp disinfected instruments, and scions, and stocks of similar diameters. Young plants grow rapidly after they have developed proteoid-roots. Some Macadamia grafters choose to add soil taken from older and well-established cultures to the propagating medium.
Step 5) This results in a significant improvement in crop growth. Small, regular additions of leaf fertilizer are beneficial to the tree nursery. By grafting, the period from planting until the first fruit can be harvested is shortened from about 7 to 3 years.
Step 6) Growing Macadamia nuts from seed are not difficult but you will find the resulting trees to be variable.
Step 7) Use well-drained soil in small amounts, but deep pots, to accommodate the taproot. Planting nut seeds in this manner allows the taproot to form properly. Some growers swear by soaking the seed overnight in water to help the germination process while others state this is not necessary. It seems worth a try since the process is simple.
In case if you miss this: Pine Nut Cultivation.
Irrigation and Organic Fertilization Management in Macadamia Nuts Farming
Keep the soil of the Macadamia tree slightly moist and water the young Macadamia tree regularly. During the first 4 years, animal manure and also thick mulch can be used throughout the whole year. After that, care must be taken that not too much animal fertilizer is applied, causing an excess of nitrogen and deficiency of potassium, and the pH-value to rise sharply. In the case of organic fertilizer with strong nitrogen content, such as fresh dung, the yearly cycle of the trees should be considered, so that a rise in growth is not stimulated during the nut formation phase. Soft leaves and fewer proteoid roots are mainly caused by soil that contains too many nutrients.
Examples of fertilizers used;
- Sowing with ground-covering green fertilizer plants
- Algae fertilizer (rich in trace elements)
Macadamia trees are specialized in extracting nutrients directly from decomposing organic substances within soils of low fertility.
Pests and Diseases Management in Macadamia Nuts Farming
A healthy Macadamia tree is pest-free, but thrips, mites, and scales might attack it. Mostly they are deterred by the tree itself. Then, the use of organic pesticides is recommended in case of a large infestation.
Major Pests – The major pests are Macadamia Nut Borer, Tropical Nut Borer, and Stink Bug.
Major Diseases – The major diseases are Anthracnose, Husk Spot, Raceme Blight, Slow and Quick Tree Decline, and Stem Canker.
A Macadamia tree requires a lot of management for profit and good nut quality. Because they are susceptible to several pests and diseases, they require regular monitoring and control measure applications.
The Macadamia tree is easy to grow and does not require special care against pests and diseases. Some of the problems are;
Symptoms – Black lesions on plant leaves and fruit; soft black lesions on husks of nuts followed by the decay of nuts on the ground; shells of infected husks could turn brown-gray but the kernel inside remains unaffected.
Management – For controlling anthracnose, avoid stressing trees by providing them with adequate irrigation and control insect pests to prevent stress to trees.
Symptoms – The symptoms are chlorotic to yellow flecks on the husks which enlarge and develop tan brown centers; circular tan spots develop inside the husk but shells and kernels remain unaffected.
Management – If a variety of Macadamia being grown is susceptible to the disease then an appropriate protective fungicide must be applied to the fruits; remove and old and diseased husks from the tree to reduce inoculum levels.
Symptoms – The symptoms are small brown color spots on flower petals that spread to racemes (flower stalks); racemes turning black and dying.
Management – Fungicide application is not warranted unless infection occurs in trees during wet weather which can cause severe infections.
Macadamia nut borer
Symptoms – Entry holes in husks of nuts, close to the panicle; infested nuts drop from tree prematurely; insect eggs are scale-like and are laid on the surfaces of green husks; larvae are legless grubs which are pinkish when mature with dark green spots; the adult insect is a red-brown moth.
Management – Control of this problem can be difficult as insecticides are ineffective once the larvae have entered the nuts; appropriate insecticides must be applied if green fallen nuts exhibit damage or live, unparasitized eggs are present on the tree; old nuts must be removed from the tree and the orchard ground at harvest.
Tropical nut borer
Symptoms – Numerous round holes about 0.5 mm in diameter on husks; extensive tunnelling through husk and shell visible when the nut is cut open; in late-stage infestations, the entire kernel can be consumed.
Management – For controlling this problem, use resistant Macadamia varieties and avoiding varieties prone to stick tight, and removing damaged nuts from the orchard; and applications of appropriate insecticides can be necessary.
Pruning Requirement in Macadamia Nuts Farming
Prune in early spring with pruning shears to promote a single strong trunk and 6 to 8 horizontally growing scaffold branches spaced evenly along with the height of the tree. Clip off the vertically growing shoots as they will not produce nuts. Also, prune off dead and damaged wood. The Macadamia nut tree is a bushy plant, it requires pruning. Use pruning shears to prune the plant at the beginning of the spring season.
When and How to Harvest Macadamia Nuts
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Macadamia nuts mature in 6 to 7 months after flowering and must be allowed to ripen on the trees. The Macadamia nuts fall to the ground between March and September. As the Macadamia nut dries over the next few weeks, the moisture content falls and the kernel shrinks away from the inside of the shell. Then, this allows the shells to be cracked without damaging the kernel.
Macadamia nuts yields vary with location, season, variety, and management level. The Macadamia tree is expected to yield a peak of 3.5 to 4 tons of in-shell nuts per hectare at maturity.
Commonly Asked Questions about Macadamia Nuts Farming
How long does it take for a Macadamia tree to bear fruit?
It takes 6 to 7 years before the tree will start to produce nuts, but once it has matured it is to produce more than 50 kilos of nuts in its shells each year.
How many nuts does a Macadamia tree produce?
Macadamia tree will yield 1 kg per tree per year at about 5 years of age, to more than 20 kg per tree per year at year 12, or 7 tonnes per hectare of nut-in-shell.
Can you grow Macadamia trees in pots?
Grow Macadamia trees in a pot, but change the potting mix every couple of years.
How much water do Macadamia trees need?
Usually, mature Macadamia trees can easily use up to 350 Liters of water or more a week in hot dry weather conditions. Usage may require up to 5 megaliters per hectare per year.