• How do I know if my land is suitable for truffle cultivation in South Africa?
• What are the costs and returns on truffles?
• Planting the trees
• Taking care of the plantation
• Harvesting Truffles

How do I know if my land is suitable for truffle cultivation in South Africa?

Truffles do well in areas with cold winters (average daily July temperature of 1-10 degrees Celcius) and hot summers (average daily December temperature of 17.5-22 degrees Celcius). The truffle needs summer and autumn rainfall. Annual rainfall of between 600 and 1450 mm is suitable, although low rainfall can be supplemented through irrigation. Soils should be well drained with a pH level of 7.6-8.3. Soils with this pH have been achieved through the addition of up to 100 tons of lime per hectare in Australia and New Zealand. Truffle trees prefer a poor quality, rocky soil that is low in phosphorus and nitrates. North-facing areas are preferable but not essential.

Truffle trees should not be planted anywhere near other trees that have competing fungi on their roots and we will advise you about these upon request. The black truffle is a fairly fragile, non-competitive fungus, and needs to be given an edge over competitors.

WARNING

The information provided on this site is intended only as a guide, outlining the basics of growing and cultivating truffles. We recommend that any reader interested in growing truffles seek expert agronomic and financial advice applicable to their geographic region before risking a capital investment. We also recommend that you understand the risks associated with the growing and harvesting of truffles. Historical results are no guarantee of future returns. Particular geographical characteristics can vary greatly and have significant impact upon the growth and yield of truffles.

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What are the costs and returns on truffles?

These will vary from grower to grower and site to site depending on a range of factors including:

• Topography and soil type - influencing amount of preparation and irrigation required, and rate of fungal growth.
• What use can be made of existing infrastructure eg. if a client has a suitable pump or water source, the investment cost in irrigation per hectare will be lower than if starting with nothing.
• Scale of operations.
• Lag time between investment and planting, and harvesting of truffles in good quantities.
• The level of management and understanding farmers have in what they are growing.

The costs to establish from scratch

If you are starting from scratch, costs can be high. Here is an illustrative guide of the likely investment per hectare to establish your plantation.

Irrigation infrastructure:	R20 000
Lime, soil rectification and preparation:	R12 000 (excluding transport)
Planting trees	R1 400
400 trees @R140 per/tree	R56 160
Fencing	R15 000

TOTAL COSTS: R105 000 per hectare

Some of these costs may be tax deductible. Obtain further information on this from your tax advisor.

We recommend growing grass for hay between tree rows to be used to offset annual maintenance costs.

Comparison of costs with other crops

This comparison with irrigated potatoes, macadamias and irrigated avocados identifies direct costs only, which exclude irrigation infrastructure and capital investment (such as tractors and fencing).

Comparative direct costs/ha

Truffles:	R65 400
Irrigated avocados:	R28 096
Macadamias:	R24 040
Irrigated potatoes:	R41 849

Comparative yields

Experience has shown that truffles may start to be found in year four with some reliability. However, for budget purposes we would strongly advise working on conservative assumptions and budget on first finding truffles in year six to seven. With good management of the plantation you could expect to find 2-4 kg per hectare from year six to seven and increasing eventually to 30-60kg per hectare annually from year 10 onwards. There is an example of a plantation in the Bay of Plenty in New Zealand achieving over 200kg per hectare annually but this is an unusually high yield.

Illustrative returns per hectare calculated on a conservative R8 000 producer price/kg:

Although truffles take a while to show a return on investment, by year 15 the cumulative returns per hectare significantly outstrip other high earning agricultural crops, such as irrigated potatoes, macadamias and irrigated avocados.

Comparative gross cumulative margin per ha (by year 15):

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Planting the trees

The number of trees that should be planted depends on what one wants. Our recommended density is 400 trees/hectare. For a small home orchard, 10 trees should ensure a successful annual harvest. The number of trees required for a successful commercial plantation really depends on how much you want to invest in truffles, and how much you wish to earn. A well-managed hectare of truffles can be expected to produce between 30-60 kg a year after 10 years, although one could expect smaller yields in earlier years. The biggest plantation in the world is in Spain. It has 150 000 trees and several tons of truffle are harvested annually.

1. Choose land that is climatically and edaphically suitable for truffle cultivation.
Truffles do well in areas with cold winters (average daily July temperature of 1-10 degrees Celcius) and hot summers (average daily December temperature of 17.5-22 degrees Celcius). Truffles require summer and autumn rain or irrigation. Annual rainfall should be between 600 and 1450 ml, although low rainfall can be supplemented through irrigation. Soils should be well drained, and can be of poor quality, as truffles seem to prefer rocky soil that is low in phosphorous and nitrates. Well drained soils in South Africa include Hutton, Clovelly, Humic and Shortland soils. North-facing sites are preferable.

2. Be sure that the oak species is most suited for your area
There are many trees known to host the truffle fungi, among them Quercus robur (English oak, otherwise known as Pedunculate or common oak), Quercus ilex (Holly oak or Holm oak), Quercus pubescens (Downy oak), Carpinus (the Hornbeam), and Corylus avellana (Hazelnut trees). The two main varieties of oak tree that are recommended for South African conditions are Quercus ilex and Quercus robur. Truffles ofAfrica has also successfully inoculated Quercus palustris (Pin oak).

3. Decide on a plantation design that optimises management.
There are a number of contrasting opinions on the best design for a truffle plantation. In its natural environment the black truffle generally grows beneath isolated trees, or trees that are at the edge of a forest. Many of Europe's plantations are therefore rather sparse, sometimes with fewer than 200 trees per hectare. On the other hand, a closer packing of the trees encourages vegetative spread of the fungus among the roots of the trees. As a result, some plantations are closely packed, with as many as 2000 trees per hectare. However, overcrowding may place the trees under stress, with fewer resources available for the truffles. Root contact can also increase the spread of competing species of fungus. Closure of the tree canopy is also not recommended for successful growth of black truffles. So overcrowding should be avoided. One could begin with high densities while the trees are small, since this will increase the likelihood of early production. Later, as the trees grow in size, they should be thinned to prevent crowding. Based on the experiences in Australia where good yields have consistently been achieved, we would recommend a 400 tree/ha density.

4. Prepare the soil.
Once the site has been chosen, it should be plowed to remove existing vegetation, and to enable easy application of lime and fertilizer. It is best to install irrigation lines at this point in the process. The soil should then be tested to measure its natural pH, buffering capacity, organic matter content and the availability of plant nutrients. The ideal soil pH is 7.9, although it may range between 7.6 and 8.3. Lime can be added to soils with lower levels to raise the pH. Once the ideal pH is reached it will need to be maintained with supplemental lime applications as necessary since rain water tends to leach calcium from the soil and reduce pH over time.

However, while pH is important, it is not the only factor as far as soil conditions are concerned. There are many other factors we consider in the soil sample that will impact on production and we will advise growers on how to get those in balance for production.

You should also correct for serious deficiencies in plant nutrients. Although truffles often do better in relatively poor soils, they suffer if nutrients are seriously deficient. On the other hand, it is important not to over-fertilize, as this may favour competing species or fungus.

5. Plant the saplings.
The trees can be planted at any time of the year provided they are watered properly. Planting holes should be dug a spade wide and a spade deep. Clods should be broken up when filling the hole to prevent voids around the tree's roots. The soil should then be drenched to collapse any remaining spaces around the roots. This will improve the chances of the tree's growth and survival during the first year.

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Taking care of the plantation

Once the trees have been planted, the seedlings should be protected from browsing until they grow large enough to endure it. It is very important to control weeds and grass growing near to the trees, as these will deprive them of water and nutrients, which could kill them. Irrigation through the first year or two is helpful to ensure survival.

Once the trees have become established, a bare ring, called a 'brule', forms around the base of the tree. This area looks burnt, since very little else can grow here. This is due to a process which inhibits the germination of certain seeds that attempt to grow above the fungi. This phenomenon can be seen under trees of less than two years of age, and whilst it is not a guarantee that the tree will produce truffles, it is a sign that the fungus is present and active. (The word 'brule' comes from the French word for 'burnt' or 'scorched'.)

You should aim to maintain appropriate soil moisture and temperature conditions through irrigation, weed control, soil aeration, mulching, and fertilization where necessary. Maintaining the soil pH is a very important aspect of maintaining your plantation. In time, the trees will need to be pruned on a regular basis. Avoid tilling too deeply, as this could damage the roots.

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Harvesting truffles

Truffles should begin to appear 4 to 6 years after planting, and should be in full production 8 to 10 years after planting. Truffles are generally found at a depth of around 10 - 15cm. Because they have a very strong scent, you can use hunting dogs to help you in locating them. (Pigs were traditionally used to find and dig for truffles, but dogs are easier to train, and less likely to damage the truffles). You should harvest the truffles carefully to avoid damaging them. Once they have been harvested, truffles only have a 2-3 week shelf-life, so efficient handling and distribution is essential. Again, we will assist you with the process through field days and regular newsletters.

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