Olives: Cultivation Techniques for More Liquid Gold

The use of new technologies in agriculture can help generate more yield per unit area while saving resources such as water, energy, labour, and time.

This is demonstrated by the example of the booming olive cultivation industry in Portugal.

The thermometer reads 35 degrees Celsius and it is dry in the Alentejo region in southern Portugal. During these days, in early September, rainfall is scarce, yet the olive plantations are sufficiently supplied with water and promise a good harvest. The olive trees receive water through a drip irrigation system. The two-centimetre-wide plastic tubes can be seen lying on the ground surface, winding alongside the trunks along the long rows of trees until they are barely visible. Most of the olives still hang green on the branches. Occasionally, the stone fruits already show a hint of dark violet. The harvest is imminent, beginning in mid-September and lasting nearly three months.

Olive Trees Almost to the Horizon

Rising above the rows of trees, the oil mill can be seen in the distance. On this day, a visiting group of around 30 agricultural engineers from around the world receives an insight into the operations of Bolschare, the largest olive producer and processor in Portugal. From the roof of the olive mill, we can see hundreds of metres into the distance, with olive trees stretching almost to the horizon, row upon row, tree beside tree. Occasionally, the rows are interrupted by a large oak tree. Cork oaks and holm oaks are protected in Portugal, and the felling of these ancient trunks must be approved by the authorities.

Bolschare's sustainability manager, Diogo Pires, explains that the company aims to leave 15 percent of its total land area untouched for ecological compensation purposes. So far, this figure stands at around 10 percent. Through olive cultivation alone, Bolschare today manages between 5,000 and 6,000 hectares in Portugal and partly in neighboring Spain. The avocado, almond, and hazelnut business is of secondary importance. Indeed, olive cultivation in Portugal has expanded significantly over the past five to six years. In economic terms, Portugal has now become the fifth-largest exporter of olive oil, with a growth in business volume of over 250 percent since 2017, explains Vasco Fitas Da Cruz, professor at the University of Évora and co-organizer of the excursion. This is attributed to improved cultivation efficiency, namely a better olive oil yield per hectare. Nevertheless, there is growing concern about the environmental and social sustainability of intensive olive cultivation in Portugal. Through the current harvest, which extends into November, the country is expected to produce approximately 6 percent of the world's olive oil output. This represents an increase of 10 percent compared to the previous 2022/2023 campaign. Only Spain, Italy, and Greece produce more olive oil.

Portugal's cultivated area has remained nearly constant over the past three years, at around 380,000 hectares, which accounts for approximately 4 percent of the country's total land area. But how is it possible that olive oil yields have been increased so dramatically on the same surface area? For one, more trees are planted per hectare today — up to 400. In older olive groves, planting density varied between 40 and 50 trees per hectare.

Drones assist in detection

In addition, automation has contributed significantly to increasing olive volumes. At Bolschare's plantations, all possible work processes are partially automated. Drones regularly fly over the fields, identifying individual trees and detecting whether their growth is impaired. In such cases, employees know precisely where an irrigation hose might be blocked. Without drone support, inspecting the hoses would be extremely time-consuming, and the trees would sometimes have to suffer prolonged drought stress.

Three drone pilots are deployed for this purpose, explains sustainability manager Diogo Pires. Bolschare tries to use the resource of water as efficiently as possible. "We reuse the water used in pressing olive oil for irrigation," explains Pires. More and more olive rows are covered with grasses in the middle. This is intended to keep the soil cool and reduce water evaporation. Pires continues: "We also want to plant greenery between the trees in the future in order to save water."

GPS navigation to the oil mill

Bolschare currently generates electricity via photovoltaics on the machinery halls and the oil mill, as well as at the stations where water pumps are located throughout the plantation. The trucks transporting the harvest to the mill are guided through the plantation by GPS to find the most time- and energy-efficient route. "They are not yet driving autonomously, because regulations require a driver to be seated in the cab," explains Pires. Incidentally, the harvest used for table olives preserved in brine and that which is mechanically pressed for Vergine or Extra Vergine olive oil are, at least in this mill, identical. "For the extraction of olive oil, the harvest must not be more than 24 hours old," says Pires, as the visiting group sets off through the plantation in two minivans.

Labour is valuable and scarce

The excursion participants share one thing in common: they are all researching and developing methods and technologies for the agriculture of tomorrow. Among them is a work scientist from Switzerland who studies how new technologies affect the labour time requirements of farmers, because the use of such technologies does not in every case reduce the workload or make the work easier. This knowledge is essential for farmers when they are considering purchasing a new machine, growing a new crop, or when the question arises as to whether a partner can work outside the farm, at what capacity, and whether non-family support is needed or not. The Agroscope scientist explains that the shortage of agricultural labour in Switzerland is already a significant challenge today.

Small-scale agricultural landscapes are fit for the future

Next, the group turns its attention to Bolschare's efforts in the area of species conservation. The biodiversity promotion areas are not immediately visible, and wildlife such as wild boar and roe deer do not cross our path on this day. Then the biodiversity promotion area finally comes into view — though not quite as one knows compensation areas from Switzerland. Dry shrubs and grasses grow wild over one another on a modest parcel. Two pallet structures for solitary wild bees line the edge, while several hives for honey bees stand in the center. These areas are not irrigated and therefore appear somewhat bleak. In the temperate regions of the world, shrub-lined parcel edges often gleam green and lush, alive with buzzing and birdsong. This is also the case in Switzerland, where such features are still more frequently present in the landscape than in this plantation.

Danish farmer and agricultural technology professor Claus Aage Grøn Sørensen expresses his conviction that future drone and machine technology will need to handle a great diversity both in the field and on farms. When asked whether Switzerland can benefit from the increasing precision agriculture or whether it prevents family farms from surviving due to costly investments, he responds optimistically. Switzerland's small-scale agricultural landscape could be precisely the one that is fit for the future. According to Sørensen, however, networks are needed for the shared use of smart machinery and innovative technology, so that individual farms face less financial burden.