Avocado-cultivation Europe
Avocado-cultivation Europe: Avocado can be grown from sea level to 2,500 meters above sea level; However, its cultivation is recommended at altitudes between 800 and 2,500 m, to avoid problems with diseases, mainly of the roots.
Temperature and precipitation are the two factors with the greatest incidence in the development of the crop.
With regard to temperature, the varieties have a different behavior according to the breed. The Antillean race is not very resistant to cold, while the varieties of the Guatemalan race are more resistant and the Mexican ones are those with the greatest tolerance to cold.
Regarding precipitation, it is considered that 1,200 well distributed annual mm are sufficient. Prolonged droughts cause the leaves to fall, which reduces the yield; excess precipitation during flowering and fruiting reduces production and causes fruit to fall
Avocado-cultivation Europe: The land intended for cultivation must have good natural protection against the wind or, in its absence, establish a windbreak barrier preferably one year before the establishment of the plantation. The wind causes damage, breaking branches, fruit fall, especially when they are small. Also, when the wind is very dry during flowering, it reduces the number of pollinated flowers and consequently of fruits.
Excess relative humidity can cause the development of algae or lichens on the stem, branches and leaves or fungal diseases that affect foliage, flowering, pollination and fruit development. A very dry environment causes the death of pollen with negative effects on fertilization and with it the formation of fewer fruits.
2.2. SOIL REQUIREMENTS
The most recommended soils are those of light texture, deep, well drained with a neutral or slightly acidic pH (5.5 to 7), but it can be cultivated in clay or clay loam soils provided there is good drainage, as excess moisture It provides a suitable environment for the development of root diseases, physiological such as radical asphyxia and fungal diseases such as phytoptora.
3. CHOICE OF PLANT MATERIAL
In Costa Rica, avocado production is intended for domestic consumption. However, as the currently planted area does not satisfy national demand, it must be imported from other Central American countries and Mexico.
World trade is especially directed at European markets; 60% of the total is consumed by France followed in order of importance by Germany, the United Kingdom and Italy. The main producers are: Mexico, the United States, China, Indochina, the Philippines, Israel, Algeria, Cuba, Kenya and Spain (Canary Islands).
There are three races within the avocado: Mexican, Antillean and Guatemalan. The Guatemalan race presents intermediate characters with respect to the other two races. The Mexican is more tolerant to cold and more sensitive to saline soils than the Antillana. The fruits of the Mexican are small and contain a high percentage of oil, while in the Antillana the opposite occurs.
Avocado-cultivation Europe: The varieties are recommended according to the altitude at which they are going to be cultivated. Table 1 shows the best for each elevation.
Table 1. Avocado varieties suitable for cultivation at different altitudes.
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HEIGHT |
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From 0-1,000 masl |
1,000-1,500 masl |
1,500-2,500 masl |
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Simmonds Katherine Booth 8 Booth 7 Masutomi Kahalú |
Shock Kahalú Hall Simpson Booth 8 Guatemala Fujikawa Itzama |
Nabal (G) Aztec Strong Hass Ettinger Wurstz |
Table 2. Classification of avocado varieties according to their type of flower.
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Variety |
Flower type |
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Booth 7 Booth 8 Choquette Hall Itzama Simmonds Strong Hass Nabal Guatemala Ettinger |
B B TO B B TO B TO B B B |
Patterns
The plants used as patterns must come from native or local trees, preferably from the highlands, which have shown the best results due to their rusticity and adaptability to the environment.
There are resistant patterns to the Phytophthora cinnamomi fungus(see disease section)
4. CULTURAL PRACTICES
4.1. SOIL PREPARATION
The preparation of the land depends on the topography and the existing vegetation. If the land is flat and has been previously cultivated, it does not need preparation, it is only marked and holes 60 cm in diameter and 50 to 60 cm deep are made. If it is flat but has weeds, you must first apply some herbicide and then plow and track. Subsequently, the marking is made, which can be a real square, staggered and others.
It is convenient to build trenches following the contour lines for soil protection. It is also possible to mark for planting in contour lines to take advantage of the lines as soil conservation works.
4.2. WEED REMOVAL
When doing weed control, avoid using sharp tools near the base of trees, so as not to cause wounds that can be the entrance for the phytophthora cinnamomi avocado wilt fungus .
It is not advisable to keep the soil bare, since in these conditions it is subject to erosion; it is better to have a cover crop of legume plants between the trees, which are the best for their nitrogen contribution, in many cases easy-to-handle and low-growth grass covers are used.
Managing grass mulch can be done with a rotary mower before the mulch weeds come into bloom. When the grass cover is infested with weeds, it is convenient to use herbicides in localized applications towards them.
It is best to use herbicides when weeds sprout after mulching. If the appearance of weeds occurs, it is advisable to apply a good herbicide such as Terbutizaline, directed at the weeds.
For broadleaf and sedge species 2-4 D can be used in its salt formulation, in doses of 0.5 kg.Ha-1. For weeds that are difficult to eradicate, glyphosate is used.
When the paddock is leguminous and infested with grasses, the herbicide fluazifop-butyl (0.5 kg.Ha-1) can be used.
4.3. PRUNING
The avocado tree does not require training pruning. In the first three years of development, avocado trees require little attention when it comes to pruning, but then care must be taken to keep it well formed, so that cultivation and harvesting are facilitated.
Excessively tall upright branches, branches low or close to the ground, and weak and diseased stems should be pruned.
4.4. SPREAD
Avocado can be propagated by seed or by grafting.
Propagation by seed is not recommended for commercial plantations due to the great variability that occurs in production and fruit quality.
Propagation by grafting is the most appropriate method to reproduce the varieties selected for commercial cultivation, since the grafted trees are uniform in terms of quality, shape and size of the fruit.
The seeds should come from healthy, good-sized fruits, harvested directly from the tree. Its viability lasts up to three weeks after extraction from the fruit. It is advisable to cut the narrow part of the seed, in a section of a quarter of the total length, to help thus the emergence of the sprout and to make a first selection, since the cut allows to eliminate the seeds that do not present the natural color yellowish white, due to rot, injury or any other damage. Immediately after cutting, they are planted in the previously prepared seedbed by placing them on the wide and flat end so that the cut part is facing up. The seeds begin to sprout approximately thirty days after sowing. Generally the plants are ready to be transplanted to the nursery,
Graft
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The graft is carried out when the stem of the standard plant is 1 cm in diameter (approximately 6 months after sowing) and 10 cm from the base. It should be done in a cool and ventilated place to achieve a good vascular union between the master and the graft.
The most widespread method to graft avocado is the lateral union, although the terminal spike graft also gives good results; however, others such as the escutcheon and cleft graft are also practiced, but with less success.
The quills to be grafted must come from selected trees and representative of the chosen variety, with good vigor, without diseases, of good production and quality. It is convenient that the tines have different thicknesses to have material adaptable to the different diameters of the patterns.
The lateral union graft is performed approximately 20 cm high from the master.
Once the graft has stuck, between twenty-two and thirty days after it is made, the upper part of the pattern begins to be removed. This is becoming gradually until the graft. The cut must be made with a bevel and covered with a copper-based fungicide paste.
When the graft is between 20 and 25 cm high, it can be transplanted to the final field, as long as the cut has been covered by the graft callus.
4.5. HARVEST
Normally, the first commercial harvest occurs after five years in grafted trees and the amount of fruit produced depends on the variety and the attention that the plant has received in its development. At five years, fifty fruits are generally harvested; at six years, one hundred and fifty fruits; at seven years, three hundred fruits and eight hundred at eight years.
Some varieties such as Hass, Fuerte and others with small fruits, can produce between 1,000 and 1,500 fruits after ten years.
The lowland varieties begin to produce between April and August, those of medium heights between June and September and those of high altitude between September and April.
The optimum degree of maturity of the fruit to carry out the harvest is difficult to determine due to the diversity of varieties and environments, due to the variations in the duration of the period from flowering to harvest and due to the differences in the content of oils that accumulate during the ripening of the fruit.
The criterion of maturity that has prevailed has been based on the fat content in the fruit.
Harvesting is done by hand using a ladder, the peduncle is cut above the insert with the fruit.
Since the avocado fruit has a very intense respiratory activity after being harvested, its storage for long periods is difficult, since this characteristic entails an intense microbial activity and a strong decrease in the water content in the fruit. The magnitude of the respiration of the fruit depends on the varieties, degree of maturity and the environmental conditions of the area and storage. For this reason, the preservation of avocado fruits destined for export is carried out in chambers or warehouses with a controlled atmosphere.
5.PLANTING FRAMES
The saplings are ready for transplanting at the plantation four to six months after it was grafted.
The planting frames will be determined by the type of soil and the topography, the variety or cultivar (due to vigor, growth habit) and by the prevailing environmental conditions. The lower the altitude or the higher the fertility, the distances must be greater.
In general, the distances vary between 7 mx 9 m to 10 mx 12 m; the spacing of 10 m between plants and 10 m between rows is the most used.
There are several planting systems used: the square that can be 8 x 8 with 156 plants in one hectare, 9 x 9 m with 123 plants.Ha-1 or 10 x 10 with 100 plants.Ha-1; the staggered one that can be 8 x 8 with 180 plants. Ha-1, 9 x 9 with 142 plants. Ha-1 and the 10 x 10 with 115 plants. Ha-1.
6. IRRIGATION
During the first year of the saplings, the plantation must have enough water for irrigation during the dry season, so that the trees receive the adequate amount to achieve good development, which will be decisive in the future of the plantation.
7. FERTILIZATION
To define the amount of fertilizer that can be supplied to an avocado plantation, a soil analysis must be carried out before establishing it and approximately every three years, in addition to the foliar analysis that it is advisable to do every year. These analyzes will indicate whether the nutrient levels in the soil and in the plant are satisfactory.
In general terms, the following suggestions can be taken as a basis for fertilizing the avocado:
When transplanting: 250 g of a fertilizer rich in phosphorus such as the formula 10-30-10 or triple superphosphate, at the bottom of the hole.
For each year of the tree, one kilo of a fertilizer rich in nitrogen and potassium such as the formula 18-5-15-6-2, divided into three applications, one at the beginning of the rains and the other two each two months. The maximum amount of fertilizer is 12 kilos for trees 13 years and older. This amount will be maintained if production is constant. If the soil test indicates a low pH and a percentage of exchangeable aluminum.
When the tree enters production, nitrogen fertilization must be increased, since in the period between the beginning of flowering and fruit maturation, the tree demands the highest amount of nitrogen. An additional kilogram of urea is recommended, at the dose of the complete formula, 40 days after flowering, if there is irrigation; otherwise, it must be added at the beginning of the rainy season.
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