Project objectives and expected results

Olive cultivation is the basic tree cultivation in the Mediterranean basin and dominates its rural landscape. The importance of olive farming and the associate industry is relevant in Europe: approximately 75% of the more than 3Mt of olive oil produced in the world comes from the EC. With more than 4.8 Mha of land use, olive is the first tree crop in Europe. The importance of olive farming transcends the mere numbers of commodity produced or land use; the tree is a Mediterranean sclerophyll typical of semiarid environments, whose physiological traits allow its cultivation over large dry areas of southern Europe, which rarely admit any other alternative crop due to water shortage. The long-term adaptation to the Mediterranean climate grants to the olive tree one of the highest water use efficiencies (the amount of biomass produced per unity of water used) among all the crops cultivated in southern Europe. Moreover, olive farming represents the main and often unique livelihood for rural population of the southern side of the Community, with a notable contribution to raise the financial conditions and to stabilize the populations of otherwise very depressed rural regions, historically source of emigration towards urban areas.
Apart from the purely economic aspect, olive farming has a heavy social and environmental significance, which contribute to the sustainability of this agro ecosystem. Olive farming systems provide habitat for birds and many other animals (from mammals to reptiles), and contribute to the preservation of natural resources through the maintenance of soil, the reduction of rainfall’s losses and the carbon sequestration. In particular, for the last point, the assessment of the carbon exchange of olive groves is an open challenge that, due to the extension of land covered, is well worth to be faced.
These systems are therefore of enormous ecological and economic importance for most countries of the Mediterranean basin and this must be considered when drawing up any regional development policy.
During the last decades, the olive farming industry is experiencing an intensification process that carried along some radical changes in its thousands-year-old agronomic practices that are moving from low-input traditional plantation (with few or no chemical inputs) to intensified traditional plantation, managed under an intensive and highly mechanized system.
The introduction of irrigation boosted the production per land area; as an indirect consequence the traditional groves are being replaced – where possible – with very productive high density (400-600 plants/ha) or even super high-density hedgerow trained systems (1000-1600 plants/ha), the last ones adapted to mechanical harvesting for costs reduction.
The increase in the invested surfaces and in their density of plantation led to the first environmental risk caused by intensification: the irrigation water demand is putting the naturally scarce water resources of olive growing areas to an edge.
Another risk associated with olive farming is soil erosion: in tree crops, even under high plantation density, a significant fraction of the soil is vulnerable to the action of rainfall and runoff. Many studies point to the use of cover crops during the rainy season as the more effective way to reduce the risk of soil loss in olive groves. Nevertheless, and despite the effort of policies from local to European level, the adoption of cover crops has been scant, due technical problems due mainly to competition for water and nutrients.
Olive farming and olive oil industry also produce a number of by-products, namely residues from pruning, pomace and vegetation waters from oil mills that are always treated as wastes, while there is a strong need to ideally move these materials from the category of wastes to dispose of to that of by-products that can generate benefits. The use of these materials as sources of energy is pushing a relatively novel industry in the olive growing areas.
The current forecasts of climate change will likely worsen this picture, and in a way that is difficult to address quantitatively. Recent studies pointed out that since cultivated area of olive tree is limited to specific climatic niches, temperature and rainfall changes will put its cultivation at greater risk. Much evidence indicates that, during the last two millennia, the extension of its cultivated area changed and the climate was the main variable driving this process. Accordingly, climate change is expected to produce a large impact on olive tree distribution, where Southern Mediterranean region may become unsuitable for its cultivation because pf the joint effect of higher temperatures and reduced soil moisture while other regions, nowadays too cold, may become viable for olive tree cultivation following the warming trend.
Yield quality may be affected as well, since environment together with the cultivar is the factor with the highest impact on fruit and oil quality. Climate change is therefore raising serious concerns about possible variations caused by increasing temperatures and reduced rainfall, which are highly likely to be detrimental to fruit quality.
All that considered, given the economic importance of this cultivation, along with additional ecosystem services provided, it would be of primary interest to include actions to predict the impact of climate change on olive cultivation in order to define adaptation/mitigation strategies and to support long-term investment decision making. The most important expected results of this study are as follows:
1) Yield performances under different climate scenarios
2) Increase the accuracy of process-based olive tree model to predict olive yields in response to higher temperature and [CO2];
3) Explore scenarios of olives production, in relation to various agro-management options and presence of biotic/abiotic stressors; 3) Evaluate quality of products and by-products under climatic scenarios;
4) Develop adaptation techniques in accordance with stakeholders;
5) Optimization of agronomic design.