Status and perspectives for rice irrigation in the Mediterranean Basin

Abstract

Rice is cultivated on approximately 1,000,000 ha in the Mediterranean area, with production concentrated in Egypt, Italy, Türkiye, Spain, Grece and Portugal. In these areas, rice is traditionally established by wet seeding and cultivated under continuous flooding (WFL), which requires larger volumes of water compared to other irrigation practices. The aim of this study is to benchmark irrigation methods alternative to WFL across sites representative of the rice agro-ecosystems producing areas of 5 of the main rice-producing countries. For each site, WFL and one or more alternative methods, selected and adapted to site-specific conditions, were implemented and monitored for at least two years. The alternative methods included: alternate wetting and drying (AWD), dry seeding and delayed flooding (DFL), water input/output reduction (WIR), hybrid irrigation (HYBRID), sprinkler irrigation (SPRINKLER), surface drip irrigation (DRIP), and subsurface drip irrigation (SDI). The results suggest that AWD, DFL and WIR, which are easy-to-implement flooding techniques, increase water productivity (WP) and preserve yield production. Both SPRINKLER and HYBRID showed a higher increase in WP (by about 50%) while maintaining or even increasing yield production, but at the cost of changes in irrigation management and investments for equipment purchases (limited in the case of HYBRID and greater for SPRINKLER). DRIP and SDI increasing WP by more than 100% but, sometimes, yield was significantly reduced. Additionally, pressurized irrigation methods, and especially DRIP and SDI, showed the need for careful consideration of site conditions (during system design and management) to avoid yield losses.