Background
The Olive Tree has been known for approximately 5,000 years in the Middle East (ancient Mesopotamian region). Its cultivation spread in the West along the Mediterranean basin from the "Acebuches" (wild olive trees) that the first growers were selecting based on productivity and adaptation. In this way, the olive trees became resistant to arid climatic conditions and diverse orographic circumstances, coexisting with crops such as the vine, the almond tree and the fig tree.
Most historians agree that cultivation for olive oil began in Crete during the Paleolithic and Neolithic periods (5,000 and 3,500 years BC). The first writings on olive oil were found in the Minoan Tablets that constitute the most important archaeological testimony about the Olive Oil that was part of the Cretan economy at the time of King Minos, around 2500 years BC. in the Neolithic sites of El Garcel.
In Egypt, 5000 years ago olive oil was used as fuel to illuminate the temples, the Egyptians being one of the first civilizations that practiced the extraction of oil by mechanical procedures similar to those used today. In the kitchen even then it was used to dress lettuce. Baths with scented olive oil were also frequent. Ornamental crowns made from olive branches have been found in Pharaonic tombs.
Between the 11th and 14th centuries BC, the Phoenicians began to spread the olive tree throughout the Greek islands and the Hellenic Peninsula. Its cultivation increases and reaches great importance when Solon promulgates decrees to encourage its planting. Olive plantations began to spread throughout Europe from very ancient dates in Pontus, Mytilene and Armenia. Greeks, Phoenicians, Romans, Jews, Carthaginians, Arabs, Hispanics and other peoples who traded on the shores of the Mediterranean Sea, were in charge of spreading the cultivation of the olive tree, and the use of its fruits (olives). Already then many of the virtues and benefits coming from the olive tree were known.
In Greece, the olive tree was the most widespread and cultivated tree, protected by severe laws, which punished people who dared uproot more than two olive trees with exile and confiscation of all property. In Greek mythology it is mentioned how Athena made the olive tree sprout from a spear, saying: “its fruits will not only be good to eat, but also an extraordinary liquid would be obtained from them that will serve as food for men, rich in. The branches of the olive tree have been a symbol of peace, victory and life. It was considered as a tree of fertility, so women slept on its leaves and under its shade when they wanted to beget.The wood of the olive tree was used to carve statues of the gods, scepters of the kings, tabernacles and instruments of combat. The Greeks promoted the cultivation of the olive tree in Italy, where it was easily adapted. In this way, the olive tree spreads throughout the Mediterranean basin, passing to Tripoli and Tunis, to the island of Sicily and, from there, to southern Italy. Already in Italy it soon spreads to the north, from Calabria to Liguria.
The cultivation of olive trees on a large scale, using Greek olive growing systems, happens first in Sicily, where the olive groves of Agrigento were famous. Tradition indicates that Romulus and Remus, descendants of gods and founders of Rome, saw the first light under the branches of an olive tree. Among Romans, "oleum" (olive oil) was a true luxury to which the high castes attributed the secret of its beauty, because they used it to care for their skin and hair. There was clandestine trade so that the town could obtain olive oil, but the cultivation of olive trees began to decline in the Roman Empire, due to the high taxes that producers and merchants of the product had to pay, which caused the abandonment of olive growing and, From the second century on, Rome was forced to import Spanish olive oil.
Oil from Hispania was highly esteemed, so to encourage olive oil transactions, the emperors abolished all public tributes to those engaged in the private oil trade. The transport of olive oil was entrusted to the «navi oleari», who unloaded the merchandise in Ostia and, from there, it was taken to Rome. For this reason, the cultivation of olive trees in Spain was notably increased, especially in the Guadalquivir valley, during the eight centuries of Hispano-Arab civilization.
The Arabs introduced olive varieties in the south of Spain, and they had a notable influence on the spread of the crop, to the point that Castilian words such as olive, oil or wild olive have Arabic roots. The Spanish word "oil" comes from the Arabic "al-zait" which means "olive juice." Olive oil was so highly appreciated by Muslims that the Koran itself praises it (24,35). At the time of the Catholic Monarchs, the "gazpacho" with olive oil and vinegar, was a fundamental part of the diet in Extremadura and Andalusia. In 1492, Spain brought the olive tree to America. The first olive trees left Seville for the Antilles and later to the American continent. The Spanish brought olive trees to Mexico, Peru, Chile and Argentina, mainly between the 16th and 17th centuries.Today it is possible to find olive trees in California and different regions of Latin America.
Currently the country with the most olive trees is Spain, followed by Greece, Italy, Tunisia, Turkey and Syria. Spain ranks first in world olive oil production, with an average annual production between 700,000 and 800,000 tons, sometimes reaching more than 1,000,000 tons. Spain is also the world's largest exporter of olive oil. At the national level, the largest volume of olive oil production is in the Andalusia region 80%, followed by Castilla la Mancha 6 and 7%, Extremadura 5%, Catalonia 4%, the rest of the production in Valencia and Aragon.
Olive tree characteristics
The olive tree (European olea) is a tree belonging to the botanical family of oleaceae. Within that family it is the only species with edible fruit. Its main characteristics are: shiny dark green leaves, whitish on the underside, simple, lanceolate in shape and entire edges. It is an evergreen tree, its leaves usually live two or three years. The flower is small. The thick trunk and its grayish bark. The fruit is the yellowish green olive, whose pulp is oily once it has reached maturity. The pit inside the fruit encloses the seed. The olive tree branches low and its branches tend to disperse. It requires a lot of sun and is damaged by excessive humidity. It is a centennial tree that begins to produce fruit from three years of age. Its production already in shape begins between the seventh and ninth year,and it increases with increasing age. Their productivity stabilizes between 65 and 80 years of age.
They are slow-growing trees, but they have a great quality: by carefully digging and packing without damaging its roots, the tree can be moved whatever its age; in fact there are companies dedicated to the sale of adult olive trees for decoration. Its height reaches 25 meters, and its trunk a diameter between 8 and 10 meters, but the usual thing is that a pruning is practiced every two or three years, to keep it between 4 and 8 meters high. Olive wood is hard but easy to polish and ideal for carving utensils. It is definitely a tree that combines elegance and robustness. Regarding the fruit, the olives destined to obtain oil are harvested ripe between December and February, and those destined for seasoning are harvested half-ripe between November and December.
Climatic factors
The olive tree is associated with areas with a Mediterranean climate characterized by mild winters and warm summers, with practically no rain. The olive plant grows and bears fruit appropriately between latitudes 30º to 45º in the northern hemisphere and 40º in the southern hemisphere. Ideal altitude between 250 and 500 meters above sea level. Ideal temperature between 35ºC and -8ºC. The olive tree is capable of withstanding temperatures of 40ºC. Sprout growth begins when the days are several hours over 21 ° C.
The olive tree requires heat accumulation around 4,100 ° C from flowering to ripening of the olives, understood as a color change, from a yellowish green to purple. The most serious meteorological parameter for olive trees is excessive and permanent environmental humidity that favors the development of diseases caused by fungi, which mainly affect during the flowering period causing the fall of flowers. Dry winds and high temperatures during flowering cause generalized ovarian abortion, seriously affecting production. The olive tree is a tree hungry for light, so a deficiency of this reduces the formation of flowers or makes them not viable. The parameters of rainfall for the olive tree are between 250 and 500 mm. yearly.The hours of sunshine needed around 2800 per year.
Edaphic factors
The physical characteristics of the soil that affect the growth of roots in olive trees are: texture, depth and aeration. The olive tree behaves better in soils of medium textures: loam, sandy loam and clay loam. These types of soil allow proper permeability, moisture retention, and aeration for root growth. Considering the rather superficial growth habit of the olive tree roots, soils with a useful depth between 0.8 and 1.2 meters are suitable for its development, especially when technified irrigation systems are used. The saturation of water in the soil profile is highly detrimental to the olive tree, since this species is very sensitive to root suffocation. Water saturation usually occurs in soils with a very clayey texture, or with impermeable layers. In these cases,the construction of ridges favors the growth of the roots, as they have an adequate environment of air and humidity.
On the other hand, the chemical characteristics of the soil such as acidity and alkalinity (PH), salinity and possible toxicity by boron and chlorides must be known before planting. The olive tree grows well in soils that range from moderately acid to moderately alkaline (pH between 5.5 and 8.5). The salinity level is expressed by electrical conductivity (EC). A soil is considered saline when it has an EC of 4 deciSiemens per meter (dS / m) measured in its saturation extract. The presence of high concentrations of boron and chlorides in the soil can negatively affect the development of the olive tree.
Olive plantation
The first is an analysis of the soil and subsoil. The optimum clay content should be between 3% and 35% (maximum 50%); silt should be between 5% and 35% (maximum 45%) and sand between 45% and 75%. Almost all soils are susceptible to planting with the exception of soils that are too clayey, saline or with large accumulations of gypsum. On slopes below 10%, the ideal orientation is 16º North, to ensure the sun's rays on both sides of the olive grove line. A planting frame of 8 × 6 in rainfed conditions and 8 × 5 in irrigated conditions is recommended. An 8 m street between olive trees is always advisable. The trees at the time of planting must be at least one meter high or nine months old.
Olive trees must be purchased with a certificate of quality, health and variety. Holes of 1x1x0.6 mt will be opened. or 0.8 × 0.8 × 0.6 mt. When excavating, the vegetative soil will be set aside and the subsoil soil on the other, putting the vegetative soil into the hole first. Planting will always be carried out with the guarantee that no frosts will fall, when the minimum temperatures are well above 7 ºC and the maximum temperatures are below 30 ºC to avoid dehydration. The saplings are placed directly in the center of the hole, aligned by guide stakes. They should be planted in the topsoil inside the hole and covered with it, leaving a part of the hole unfilled for future watering. Once planted, they will have to be watered, regardless of whether the soil is damp or not, to avoid dehydration.Put a stake at least 1.20 m high to prevent the prevailing wind from moving the trees, which must be protected with mesh in case there is a rodent problem. Generally the planting density ranges between 200 and 300 trees per hectare.
Flowering, Fruit and Harvest
The flowers begin to appear at the end of March, it is when it is said that the olive trees rap. The true flowers appear in the months of April and May, although the most abundant occur in April. In June we already have olives formed that during the summer and autumn increase in size, and go from green to purple and black. The olives are harvested between November and February. In the past when they were harvested manually, the harvest lasted until March. For an effective management of the plantation it is necessary to know the tree canopy volume, since on this basis it is possible to make important decisions.
In rainfed olive groves, rapid and free growth of the tree canopy is allowed up to 8,000 cubic meters per hectare, and no more than 12,000 cubic meters of canopy per hectare in irrigated olive groves, so the necessary pruning will be necessary to maintain the aforementioned glass volumes. Exceeding these volumes would only pose more problems for the olive grower, such as poor fruit quality, difficulties in harvesting and phytosanitary problems. Based on these concepts, widely experienced production models are developed that allow us to obtain, both in temporary and in irrigation, excellent productions. For example, it is usual in Andalusia, Spain, to obtain productions in intensive irrigated olive groves of 12 and 15 tons per hectare during the adult period of the plantation,having reached productions of up to 30 tons per hectare.
Olive varieties
In Seville, Spain, the most renowned olive varieties and therefore most used in plantations are the following: Gordal, Manzanilla, Zorzaleña, Aljarafe, Hojiblanca, Aberquina and Verdial, the latter highly recommended as a mother plant to graft on clay soils and somewhat flooded. In addition, Manzanilla Morón that little by little is disappearing like the Zorzaleña, Durzal and Rapazallo, likewise the Lechín also in decline.
Varieties of Olives
Picual: Large, elongated olive. Trees of this variety produce fruits in the first 2 or 3 years, it resists frost well. Yield in oil: 21% to 25%. Villalonga Chamomile: Species similar in size to Picual, but more rounded. It is used in dressings and to produce oil. Yield of 22 to 25%. Cornicabra: Produces sharp olives that can be used for the production of oil or for green table olives. Yield 20% to 23% Fine Chamomile: It is one of the species that ripens earlier. It is intended for the production of olives in green dressing. Yield 21% to 23%. Arberquina: Small and round species very resistant to cold, appreciated in the production of oil for its high yields.Blanqueta: Similar to the Arbequina. Farga: Irregular species in production, it was planted a lot before and that has been replaced by the previous ones, because the trees of this variety take longer to produce fruits. Aragonesa or Empeltre: Species that fructifies early. They are used as black olives, and to produce oil. Yield from 22% to 23%. Sevillanas: among which are the Caspe and Gordal varieties. They produce very fat fruits that are used for green dressing.
Classification of olive oil
Virgin Olive Oil is obtained by procedures that do not alter its essential properties, and is classified as: Extra: Flawless flavor and acidity expressed in oleic acid not exceeding one degree. Virgin Fino: Very good flavor and acidity of no more than two degrees. Current: Regular flavor and acidity not higher than 3.3 degrees. Lampante: Defective flavor and acidity higher than 3.3 degrees. The world production of olive oil is estimated at 2 million tons. Spain and Italy produce 50%. The European Union together 75% of global production.
