Hazelnut sounds familiar to everyone, although we usually see it “hidden” in many ingredients, such as chocolate. This fruit comes, how could it be otherwise, from the hazelnut. At Gardenprue, we are going to see some things that you may not have known about the European hazelnut .
It is known as European hazel ( Corylus avellana L.) and is a deciduous tree in the Betulaceae family . It usually reaches a height that varies between 3 and 8 meters and is usually quite branched from the base, although it depends on the pruning system we do.
Although climatically it can occur in many areas, as we will see later, in Spain it is usually cultivated more importantly in Asturias, Valencia and Catalonia. An example of how disparate your cultivation can be.
CLIMATOLOGY AND CLIMATIC FACTORS
Although, as we have commented previously, it tends to adapt to many areas, some rainier than others and more or less cold, the optimal environment for the development of European hazelnut is an annual average temperature of between 12ºC and 20ºC.
[pullquote] With an average of 12 ºC and 20 ºC, the cold-hours that the hazelnut demands for proper flowering and subsequent fruit setting are satisfied. [/ pullquote]
In winter rest situations, it supports very freezing temperatures, even below -5 ºC, although it all depends on the exposure time (little or longer) and the type of frost .
When it is in bloom, which is where it is most important to protect the crop, it supports much less cold, being its resistance around -1 ºC. Be very careful with this type of night frost that causes buds to fall, abort the flower and cause wounds that are finally invaded by bacteria ( Xanthomonas ) and fungi that further weaken the hazelnut.
On the contrary, the European hazelnut is not typical of areas where it is very hot in the summer months. Therefore, it adapts well in coastal areas, where the sea breeze lowers temperatures in summer and does not stress crops as much.
Hazelnut is a crop that demands a good dose of light , typical of warm and temperate climates. It will not have major problems due to light obstacles if it reaches considerable heights, although with height reduction pruning (to facilitate its collection), Corylus avellana L. may not exceed 3 meters.
A considerable lack of light, especially in the bud production phase , reduces the number of these of a reproductive nature, finally limiting production in that season.
IMPORTANT FACTS ABOUT SOIL CHARACTERISTICS IN EUROPEAN HAZELNUT
The soil is always an important, almost decisive factor in the implantation of any crop. We always defend their care, drainage control, periodic soil analysis and incorporation of organic matter up to optimal values (1.5% -2%).
The European hazelnut has a preference for soils of medium texture , which have good drainage and oxygenation characteristics. High clay soils retain excess moisture, which can cause root suffocation in the rainy season.
It must be taken into account that the production of roots by Corylus avellana L. has a tendency towards superficial production, rather than in depth. Therefore, it is important to take into account the presence of physical obstacles to the development of rootlets such as stones, hard or rocky layers.
In the first installation of the crop, it is advisable, if we are dealing with a soil that has not been cultivated previously, to carry out a deep plow (> 0.5 m), in order to homogenize the characteristics of the soil, break rocks, loosen and aerate the soil, also based on improving its drainage capacity.
This initial work will pay off when we plant the hazelnut and receive the first heavy rains.
FERTILIZATION AND FERTILIZATION OF THE EUROPEAN HAZELNUT
One of the most important bases to enrich the soil is the incorporation of organic matter , based on a previous soil analysis, to enrich it physically, chemically and biologically.
The recommended values, as we have commented previously, are between 1.5% and 2%. In quantities, in a generic way, they usually contribute between 40 and 80 tons per hectare.
It is interesting that said manure, compost or other origin, is decomposed, in order to be able to quickly plant the hazelnut and that it can be nourished without burning the roots in formation during its decomposition process.
HAZEL TREE PLANTATION SYSTEM
With the opening of holes of around 40 cm wide and deep it is enough to incorporate the seedlings, which originally can come in pots.
Directly, we can incorporate in these holes, a mixture of sand and organic matter, to improve the initial rooting.
Although there are different plantation frames , one that is well known and used in many areas is 5 × 4 m . This means that in each hectare (10,000 m2) we can plant 500 trees .
In other cases, the plantation frame can also be 5 × 5 m , having 400 trees per hectare (greater separation between trees with respect to the previous case).
It must be taken into account that the European hazelnut is self-incompatible monoecious. This means that its male flowers do not pollinate the female ones within the same tree.
Therefore, it is necessary to strategically plant pollinating hazelnuts , with a density that varies between 10% and 15% of the total number of trees.
Within their distribution among all hazelnuts, they can be planted in zig-zag or in complete rows (every 8 or 9 lines). Interesting in this, study the normal wind direction to see how the male pollen of the pollinating varieties will be distributed, taking into account that the majority propagation is anemophilic (through the wind).
CHARACTERISTICS AND DOSAGE OF IRRIGATION
Depending on the intention sought in the cultivation of European hazelnut , whether it is at a productive level or in an orchard, there are different ways, some more complex than others, to calculate the form of irrigation.
At the user level, cultivating hazelnuts in the orchard, the best way is to install a drip irrigation system with 2 discharge drippers per tree (4 L / ha each dripper) and irrigation for 5 hours per week (distributed over several days) in times of great demand.
In large productions or at the productive level, the best system is the placement of tensiometers that measure the resistance to absorb moisture by the roots. Sort of like field capacity and wilting point.
This reading is quantified in centibars (cb) and water offers less resistance to its absorption the lower the value.
We do this quantification, to be clear about the values, approximately:
- Reading from 0 to 10 cb : soil saturated with water. With values that tend to zero, it can cause root asphyxia due to oxygen limitation in the soil.
- 10 to 20 cb reading: ideal reading with optimum humidity percentage.
- Reading from 30 to 40 cb : water available for the plant in a soil with a good amount of oxygen and, therefore, good aeration capacity.
- Reading greater than 40 cb : water of difficult availability, suitable for crops with reduced water intake (scarcity) or optimal values for clay soils (which has a great capacity to retain water and nutrients.
- Values above 50 cb : the plant, depending on its nature and rooting capacity, comes to suffer stress due to water shortage.
HOW MANY YEARS ARE HAZELNUTS IN PRODUCTION?
Although a high production is never required in a private garden because commercial purposes are not sought, those that are intended for production usually have a life cycle of about 20-25 years.
However, hazelnut as an ornamental in garden, with hazelnut production, can be cultivated for more than 50 years without problems.
HOW MANY YEARS MUST PASS UNTIL FRUIT PRODUCTION?
Although it depends on the variety, the new hazelnuts selected on the market go into production in a few years.
The average can be between 4 or 5 years but it accelerates according to the varieties. This makes hazelnut a very interesting crop, both due to the reduced labor it requires and the net margin it leaves per cultivated hectare, around € 1,600 / ha ( Higher Technical School of Agrarian Engineering of Palencia ).
HOW MANY KG OF HAZELNUT DOES THIS CROP PRODUCE?
In full production, hazelnut is capable of producing between 2,500 and 3,000 kg / ha . If we break down this value per tree (taking into account a plantation frame of 6 × 3.5 and 475 hazelnuts / ha), between 4 and 6 kg / tree come out.