According to FAO, the world population will increase by one third between now and 2050 and agricultural production will have to increase by 60% to meet its food demand.
Climate change will make this even more difficult, due to its negative impact on agriculture, leading to spiralling adaptation and higher related costs.
The most immediate impact is the increase in rainfall and temperature variation and associated extreme weather events, such as drought and floods. In the medium-long term, climate change will affect water resources and reduce the availability and safety of water sources in many areas that already deal with water shortages.
Citrus fruit is commercially cultivated in around 80 countries worldwide and the leading production regions include arid and semi-arid regions in the Mediterranean basin such as Spain, Italy, Greece, Egypt, Turkey and Morocco. In these areas, yields heavily depend on irrigation, as rainfall is usually lower than what is needed by the crops and rain distribution throughout the season does not meet crop demands.
Citrus fruit trees are evergreen plants that require water all year round. There are times when water stress can trigger physiological responses that enable plants to cope with water shortage. Researchers from Di3A at the University of Catania, in cooperation with Acireale's CREA and the Department of Geosciences at the University of Padua, studied the effects of water stress on physiological responses, soil-plant water exchanges, crop yields and fruit quality in a grove located in eastern Sicily.
Two situations were compared: (i) full irrigation (T1), where trees were supplied with 100% of crop water demand; (ii) partial irrigation (T4), where trees were supplied with 50% of crop water demand.
Yield, fruit quality and water use efficiency (WUE) of groves supplied with 100% of their water demand (T1) and 50% of their water demand (T4) during seasons 2013 and 2014.
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Results show that, compared to full irrigation, irrigating at 50% of water demand increased orange yields by 20%. Reducing the water volume had positive effects also on water use efficiency.
"Therefore, when water resources are limited, this is an efficient strategy to increase WUE without negative effects on physiological response and fruit development," explained the researchers
Source: Consoli, F. Stagno, D. Vanella, J. Boaga, G. Cassiani, G. Roccuzzo, 'Partial root-zone drying irrigation in orange orchards: Effects on water use and crop production characteristics', 2017, European Journal of Agronomy, Vol. 82, pag. 190-202.
Contacts:
Simona Consoli
Dipartimento di Agricoltura, Alimentazione e Ambiente (Di3A)
Università degli Studi di Catania
Via S. Sofia, 100–95123
Catania, Italy
Email: simona.consoli@unict.it