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#3 TECHNICAL GUIDE – PREPARATION AND CARE

Preparation and care

Passion for agriculture

Once you’ve determined whether the plot has the right conditions to grow truffles, you should carry out the relevant preparatory work to plant the tree seedlings under the best conditions.

PREVIOUS STEPS

Preparing the ground

The work to be done will depend on the previous crop cultivated in the field in question. Here are different cases and our recommendations on what to do to promote the survival of tree seedlings and colonisation of the ground by truffles to the greatest extent possible.

Previous crop

Herbaceous crops – In this case it is advisable to use a cultivator, or similar, to break up possible plow pan created over the years.

Grapevines and fruit trees – The same preparatory work as for herbaceous crops, uprooting either the grapevines or fruit trees before starting work.  Particular care must be taken, especially for grapevines, almond trees and olive trees, as any previous problems with Armillaria sp. or any other pathogenic fungus that affects tree health can also attack the inoculated truffle tree seedlings.

Vacant land – In the case of soil that has been left uncultivated for a number of years, there are two possible cases:It is possible that shrubs or trees have grown, in which case you must first remove the tree cover by the roots and carry out the appropriate farming tasks, as they are ectomycorrhizal species (evergreen oaks, Portuguese oaks, kermes oaks and pines, among others).

It is necessary to wait 3–5 years before planting truffle tree seedlings, in order to minimise the presence of fungi that can compete with the truffles in the soil.

If there is only herbaceous cover, the same preparatory work should be carried out as in the case of having previously had cereal crops. We recommend tilling the soil a few times and planting it after a year. The truffle trees will respond much better by doing this.

In the case of plots attached to wooded areas, it is important to plant the tree seedlings a good distance away from the woods in order to minimise the impact of existing trees, in terms of both tree-to-tree competition and competing fungi attached to the roots of trees on the periphery.

In all cases, it is advisable to use a subsoiler to break up the ground before planting.  Be careful when subsoiling because many rocks emerge, you will have to remove and/or crush them afterwards.

If you grind the rocks, we recommend performing another soil analysis after this, as—depending on the type of rock—the soil’s chemical properties may be altered.

This occurs when there are many white, brittle rocks, which are usually very rich in calcium salts. When they are ground, they add this element to the soil in great quantities.

This calcium input degrades organic matter, blocks phosphorus and adds very fine particles that can modify the texture and structure of the soil, among other things.

PLANTING

Planting patterns. Densities.

The planting patterns commonly used in trufficulture are 5 x 5, 6 x 6, 6 x 5, triangular or quincunx 6 x 5, 6 x 4, or even denser planting patterns.

This means densities per hectare from about 250 plants to just over 400 plants per hectare. We would like to point out that, in addition to the aforementioned patterns, there are plantations with much higher planting densities with very good yields (5 x 4, 4 x 4 or 4 x 3)

Our advice is to consider the truffle grower’s profile in terms of their availability and whether they can carry out a certain volume of work.

Being a professional farmer, who has the time and means

required for cultivation, is not the same as being someone who is a part-time truffle grower who does not farm for a living.

Denser planting patterns require more time and dedication.

What’s more, soil fertility must be taken into account when deciding on a particular planting pattern. The tree seedlings will grow better in more fertile soil, so it might be a good idea to decrease the number of tree seedlings per hectare or simply be aware that it will be necessary to prune more often and more intensely.

 

The type and design of the irrigation system chosen will also affect the planting pattern.

CARE

Plantation management

You must understand that trufficulture is for all intents and purposes farming—as defined by the E.E.C.—in which forest species such as oaks and holm oaks are used. But generally speaking, tilling the soil, pruning and watering will be necessary.

It is also important to consider that harvesting truffles requires the time and means necessary to do so (such as dogs trained to detect them, etc.)

Here are the tasks to be carried out and the most suitable time to do them.

We would also like to point out that these needs will change depending on the age of the plantation. You’ll see what needs to be done on young plantations and older plantations alike.

Farming tasks

In young plantations, from the time of planting until 5–6 years of age, it is essential to keep the tree seedlings and the rest of the field weed free.

To this end, it will be necessary to use a cultivator, chisel plough, semichisel plough, intervine weeder or similar until you get the desired results.

On the other hand, using mechanical tools and manual hoeing around the tree seedlings are essential for them to take root, optimise their growth to accelerate truffle production, favour mycelial colonisation in the soil and help maintain soil water storage.

We would also like to point out that there trufficulture models that only till around the trees on an individual basis, or only around the entire row, leaving the rest of the plot’s soil untilled.

In producing or non-producing plantations—or perhaps this is only anecdotal—, there may be a significant number of trees with burn patches. We recommend only tilling the soil once at the end of the truffle harvest season, which is from the end of February to the beginning of April.

There are truffle growers who till all the soil and others who do so only in the truffle burn, around the tree or along the entire row of trees.

It is very important for you to always till the soil at the same depth, between 10 cm and 20 cm. Deeper tillage can lead to truffles deeper in the soil with more protection from both drought and heat in summer and from frost in winter.

Furthermore, aside from tilling the soil, you should always prune when necessary to slow down significant growth.

In the early years, it will also be necessary to remove the epicormic shoots, buds that come out of the root system, whenever necessary and at any time of the year.

Pruning serves to essentially keep the tree in its juvenile phase as long as possible as the black winter truffle (Tuber melanosporum) is a fungus associated with the juvenile phases. Once the tree and the environment have evolved, truffle production will cease.

We would like to emphasise that if you don’t have enough water, it is better not to plant. It’s absurd to make an investment without being able to guarantee production

Having said that, the most commonly used irrigation system is a microsprinkler irrigation system, without forgetting that, although other systems such as sprinklers, sprinkler guns and even drip irrigation systems are not as suitable, they can still be used.

It should also be pointed out that, when considering an irrigation system, it should be able to fulfil its objective at different times during plant growth, even with slight modifications.

Young plantations generally require supplementary irrigation although water must be provided later on to ensure production, with more or less surface area to be irrigated depending on the age and extent of the truffle burns. It must be clear that, from a certain point onwards, only full coverage irrigation can be used, as the entire area of the plot must be irrigated.

Crop water requirements also depend on the age of the plantation. In young plants, supplemental irrigation of between 5 and 15 litres per plant is usually enough for the first and second year in the field. In order to promote and maintain production, it is usually advisable to provide water ranging between 20 mm and 30 mm. (between 20 L/m2 and 30 L/m2).

People always ask how often the aforementioned quantities should be supplied. There is only one answer. The frequency cannot be generalised—not even the amounts—, as this depends on the type of soil (sandy soil is not the same as soil with more clay or more or less rocks), its depth (deeper soil can store more water) and the evapotranspiration of that soil (impact of climate).

There are probes on the market that can check for soil moisture, but it will be your own experience and knowledge of your land that will tell you when to irrigate. Aside from using probes, it is a good idea to dig into the soil with a hoe or machete to see what’s down there.

Beware of overwatering. More water can change soil conditions and actually turn out to be counterproductive, both in the short and medium term.

#1 TECHNICAL GUIDE – THE SOIL

Is it advisable to analyse the soil?

The results of the analysis should be assessed by someone who—aside from being knowledgeable about soils—is familiar with trufficulture as a soil analysis should not be read parameter by parameter but instead interpreted as a whole.

MORE INFORMATION
#2 TECHNICAL GUIDE – THE CLIMATE

Which climate is ideal?

Climate is not just about rainfall in the area. The temperatures—both air and soil—could determine the success of a Tuber melanosporum plantation, aside from rainfall and irrigation.

MORE INFORMATION
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