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Accueil du site → Doctorat → Espagne → 2016 → Response of maize and olive to climate change under the semi-arid conditions of southern Spain.

Universidad Politécnica de Madrid (2016)

Response of maize and olive to climate change under the semi-arid conditions of southern Spain.

Gabaldón Leal, Clara

Titre : Response of maize and olive to climate change under the semi-arid conditions of southern Spain.

Auteur : Gabaldón Leal, Clara

Université de soutenance : Universidad Politécnica de Madrid

Grade : Doctor of Philosophy (PhD) 2016

Résumé
Global climate projections indicate an increase in atmospheric CO2 concentration causing for Mediterranean regions an increase in both mean and maximum temperatures, an average decrease in precipitation and an increase in the temporal and spatial variability of extreme events related with rainfall, such as droughts. All these changes in many areas within Andalusia region (southern Spain) would have a direct impact on the agriculture, a critical sector with great social and economic importance. This Thesis is a further step in the knowledge of the impact assessment that climate projections may have on agriculture in the region. To achieve this purpose, two ensembles of regional climate models (ENS-EOBS and ENS-Spain02) with a bias correction in temperature and precipitation were used in order to reduce the uncertainty linked to the use of climate models. Crop development, growth and yield under these climate conditions were simulated using crop models previously site specific calibrated and validated. The assessment of these impacts aims to be useful for decision-making, allowing exploring the potential of adaptation measures to maintain or even increase the yield under future climate conditions. In this Thesis the impacts of climate change on two crops of great importance in Mediterranean regions were evaluated. On the one hand, the maize crop, a reference irrigated crop under semi-arid conditions, which was analyzed in the first two chapters of the Thesis. On the other hand, the olive, crop extensively cultivated in Andalusia, the main olive oil producer region in the World, that was analyzed in Chapter 3. Chapter 1 describes the impacts and adaptation to climate change for maize cultivated in five locations of Andalusia. For this purpose experimental data obtained from irrigated maize (FAO-700 cycle) under not limiting conditions of water and nutrients were considered. With these data CERES-Maize model under the DSSAT platform was calibrated and validated. For the consideration of climate data several sources were used ; for the observed climate, data from the Agro-climatic Information Network of Andalusia (RIA) was used and for the simulated climate, data from an ensemble of twelve regional models (ENS-EOBS) with a bias correction in temperature and precipitation over the original European project ENSEMBLES was used. The results for the end of the 21st century project a reduction in the maize crop cycle length causing a decrease in the duration of the grain filling period and then, a decrease in yield maize and irrigation requirements. In addition, the stomatal closure caused by the increase in CO2 concentration, could lead to an increase in the water use efficiency. To reduce the negative impacts on maize crop, in this Thesis some adaptation measures were evaluated. Thus, some proposed adaptations were to advance the sowing date 30 days earlier than current and to change the maize cultivar seeking to increase the grain filling period and its efficiency.

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