Opportunities and challenges for sustainable rice irrigation in the Mediterranean region

Rice cultivation covers around 1.3 million hectares in the Mediterranean basin, with Egypt, Italy, Turkey and Spain being the main producers. In Europe, Italy and Spain account for 72% of EU rice production, with around 345,000 hectares under cultivation, while Egypt and Turkey account for almost all of the production in non-EU Mediterranean countries, with around 789,000 hectares. In these regions, rice is traditionally cultivated using Wet Seeding and continuous Flooding irrigation (WFL), which requires more water than non-flooded rice cultivation and contributes to significant methane emissions. However, it also preserves unique biodiversity-rich agro-ecosystems. Nevertheless, rice remains a strategic crop for food security, particularly in Egypt, and its consumption is steadily increasing across the Mediterranean region. To address the issue of excessive water usage associated with WFL, the most promising alternative irrigation methods were tested as part of the MEDWATERICE PRIMA-Section2-2018 project in seven case studies conducted under site-specific conditions across five Mediterranean countries (Italy, Spain, Portugal, Turkey and Egypt) between 2019 and 2021. The irrigation strategies were selected with the active involvement of local stakeholder groups. The evaluated techniques included wet seeding and Alternate Wetting and Drying (AWD), Dry seeding and delayed FLooding (DFL), Water Input Reduction (WIR), DFL with enhanced control of ponding water level through automated gates (DFL-aut), hybrid Irrigation (HYBRID), sprinkler irrigation (SPRINKLER), surface drip (DRIP) and Subsurface Drip Irrigation (SDI). These methods were implemented alongside WFL for at least two years, during which time the environmental, economic and social sustainability of each irrigation strategy was assessed. The results showed that AWD, DFL, (DFL-aut) and WIR could improve water productivity (WP) while maintaining yields. More advanced systems, such as SPRINKLER and HYBRID, achieved an increase in WP of around 50%, with yields either maintained or improved. However, these alternatives require changes to irrigation management and the purchase of new equipment, with limited costs for the HYBRID system and greater investment for the SPRINKLER system. The DRIP and SDI methods demonstrated the greatest potential for water savings, more than doubling WP; however, yield reductions were observed when the systems were not carefully adapted to local conditions. For all pressurised methods, particularly localised irrigation systems such as DRIP and SDI, site-specific factors must be considered to ensure proper system design and management and thus minimise the risk of yield losses. Overall, these water-efficient irrigation strategies offer a valuable opportunity to reduce water consumption while sustaining or increasing rice yields in traditional Mediterranean rice-growing areas. Furthermore, they enable rice production to be expanded into new regions to meet rising demand.