Ecological trade-offs of water saving irrigation strategies in rice paddy fields. The Ebro Delta case study

ENG- Assessments on the contribution of human activities to global change tend to focus on single processes (e.g., climate change effects through greenhouse gas emissions), usually overlooking potential effects on multiple agroenvironmental issues and trade-offs among them. Flooded rice (Oryza sativa L.) agroecosystems are human made wetlands, playing key roles in global carbon cycling and biodiversity conservation, while also supplying staple food for more than half of the world’s population. Therefore, their agricultural management shapes, simultaneously, the outcomes of all these issues. Water-saving irrigation strategies, introducing dry periods as an alternative to conventional continuous flooding during rice growing seasons, have been developed as climate change adaptation and mitigation practice. Even though these practices can reduce water inputs and methane (CH4) emissions, there is a knowledge gap regarding their potential collateral effects on biodiversity, their temporal implications on CH4 emissions during subsequent fallow seasons, and their effects on overall agroecosystem multifunctionality. We implemented field scale experiments within the Ebro Delta region, an important temperate rice production area in Spain, to assess the effects of implementing irrigation strategies across a water use gradient (i.e., CON: continuous flooding; MSD: mid-season drainage; and AWD: alternate wetting and drying) on these agroecosystem processes