Perspectives for improving the future sustainability of olive growing in the Mediterranean area: exploring the effects of intensification and deficit irrigation

Trabajo presentado en el XVI European Society for Agronomy Congress (ESA 2020, "Smart Agriculture for great human challenges"), celebrado en Sevilla del 1 al 4 de septiembre de 2020.Olive orchard represents a key agricultura! system with huge economic and environmental relevance. Future climate is expected to show tendencies to warmer and drier conditions with large regional variability over the Mediterranean. This could threaten the sustainability of such strategic tree crop. This study evaluates the productive and environmental performance of olive orchards under different climate change scenarios and management strategies across the main olive-farming regions over southern Europe using the process-based model OliveCan. Meteorological data over olive tree cultivated area were clustered into 22 sub-climates over baseline period (1980-201 0). Future climate data (2041-2070 and 2071-2100 horizons) of GUF-CCLM4 Regional Circulation Model for RCP4.5 and RCP8.5 scenarios were used. Simulations were performed for low density LD (100 trees ha·1), high density HD (400 trees ha·1) and super high density SHD (1650 trees ha·1) olive orchards. Climate change impacts on the the sustainability of olive orchards regarding productivity and capacity for carbon capture were assessed. lmplication of new planting systems namely intensification and irrigation were also evaluated. Results showed that drier and warmer conditions are expected all over the study area, with the most negative impacts over the driest areas and under RCP8.5. Rainfed low density orchards will be most vulnerable to these expected changes. In particular, over the lberian Peninsula, a decrease in yield up to 28% is expected under rainfed conditions with an increase in its interannual variability of 20%. Meanwhile over the centre of the Mediterranean, yield increased up to 26%. lrrigation requirement for the maximum productivity are expected to increase by 5-27%. Olive orchards responses in terms of yield and Net Ecosystem Productivity (NEP) were highly influenced by deficit irrigation and intensification. Yield and NEP responses to future scenarios in the wettest clusters were more positive than those in the driest ones. Our analysis showed that productivity depends on the balance of water supply, evaporative demand and atmospheric C02. In general, the increase in CO considered in the future scenarios may compensate the negative effects of higher evaporative demand and diminished water supply resulting in an enhancement of water use efficiency and carbon capture potential in olive orchards. Even though findings of this research showed that olive orchards may benefit from future conditions, assessment of management alternatives at local scale will be a must for a better adaptability of olive orchards