This time it is time to talk about the cultivation of the olive tree. It is a plantation with multiple social and economic contributions, as well as health and nutritional benefits. It also helps to maintain the environment and fight against climate change. Its fruit is called olive and can be used for the production of table olives or for oil.
Olive is a very nutritious and healthy food. According to the Spanish Nutrition Foundation (FEN), it contains a high content of monounsaturated fats, considered to be the necessary fats that the body needs. The main fatty element in olives is oleic acid, which helps prevent cardiovascular disease by reducing LDL (bad) cholesterol and increasing HDL (good) cholesterol. It also contains fiber, sodium, calcium and vitamins A and E.
According to data from the Ministry of Agriculture, Fisheries and Food (MAPA) for last year 2,019, the Spanish olive grove occupies an area of 2.7 million hectares (16.1% of the total area under cultivation). 95% correspond to olive varieties for oil production (2,584,564 ha) and the remaining 5% to table varieties (144,904 ha). According to MAPA forecasts, it is estimated that the 2019/2020 campaign will reach 1.2 million tonnes. As for table olives, some 487,000 tons are expected.
Did you know that the Spanish olive grove occupies an area of 2.7 million hectares, and is considered the largest ecosystem created by man?
Its varietal map in very wide, in Spain are known more than 400 varieties of olive tree. In this case, we are going to classify them according to their production destination.
- For olive oil production: the most outstanding ones are Picual, Picudo, Hojiblanca, Verdial, Aberquina, Empeltre, Cornicabra and Lechín.
- For table olive production: Manzanillo, Gordal, Morona or Dulzal and Cornezuelo stand out.
When programming irrigation for olive cultivation, a series of soil and climate requirements must be taken into account, as detailed below:
The olive tree is especially adapted to dry farming. It supports high temperatures in summer, up to 40ºC, if it has enough humidity in the soil, and up to -10ºC in the middle of winter rest. It tolerates frosts, unless temperatures are below -10ºC and with the exception of very early varieties, whose fruit can be very damaged by low temperatures.
The floral induction takes place during the summer rest period. At the end of winter or early spring, the differentiation of the buds begins. With spring temperatures of 10-12ºC the vegetative development begins, the inflorescences, and the flowering takes place between 15 and 18ºC. When the summer temperatures reach 35-38ºC a vegetative stop takes place.
The olive tree tolerates saline soils and high levels of limestone, preferring sandy, deep and drained soils.
With regard to soil requirements, the olive tree is a very rustic plant that grows on all types of soil, including soils of low fertility, although it prefers deep, drained sandy soils as it is very sensitive to prolonged waterlogging. It tolerates salinity and high levels of limestone well, and is often grown on calcareous soils in the Mediterranean area.
With regard to the cultivation system used, an important aspect when planning irrigation, the olive grove has traditionally been a dry land crop. At present, thanks to the advance in the irrigation techniques, it has passed to intensive and super-intensive systems of culture, where it is necessary to determine the irrigation of individualized form.
Water needs of the olive crop
The methodology proposed by FAO to calculate the water requirement of the olive tree is the difference between the maximum evapotranspiration of the crop (ETc) and the effective precipitation (Pe). The concept of evapotranspiration refers to the amounts of water lost by evaporation and transpiration of the crop. It is recommended to irrigate in periods when ETc is higher than Pe.
The water needs of the olive tree are important in the spring, during the pre-flowering period, and in September and October. Between the ripening of the fruit and the development of the olive stone, i.e. from mid-July to mid-August, water inputs to the olive tree should be reduced to prevent the olives from having large stones.
In summary, water inputs must be programmed according to the amount of rain falling, air temperature, solar radiation, soil retention capacity and the critical periods of the olive tree in terms of water needs.
Did you know that the drip irrigation system is the most suitable for olive growing?
And it is the most widespread and the best adapted. Every drop that comes out of the emitter is immediately absorbed into the soil, forming a wet bulb from which the roots absorb water for their development. The ideal solution would be 4 constant flow type emitters, either self-compensating or turbulent, depending on the orography of the land (for any pressure between 1 and 3 bar) per mature olive tree, with flows varying between 1 and 4 litres/hour.
Drip irrigation in the olive grove has great advantages:
- It does not present water losses by evaporation and runoff, which does occur with surface drippers. It can save up to 30% of water.
- As the drippers are close to the root area, the water is taken immediately, which makes it more effective with small doses of water.
- Erosion damage on sloping soils is reduced, and good homogeneity in the application of water to the trees is achieved.
- The drippers are always in the same place and do not interfere with the work.
- Another important advantage of drip irrigation is that it allows the application of the fertilizers diluted in the irrigation water, a practice known as fertigation.
- By not wetting the surface, the growth of weeds is reduced.
- It allows the use of more saline water, as it prevents the formation of the superficial crust formed by sodium accumulation.
- The drip irrigation system prevents the appearance of fungi.
The use of drip irrigation is a system that is increasingly in demand in society, as it calls for more efficient management of natural resources. Water plays a particularly sensitive role, especially in Spain, a country characterized by its arid climate and where agriculture consumes 75% of the water.