Assessing the decoupling dynamics between agricultural growth and water footprint through a spatiotemporal analysis of strategic crops in Iran

Achieving economic growth without exacerbating water stress is a fundamental challenge in arid regions worldwide. Despite the importance of the relationship between agricultural value added (as a measure of the sector’s( and water consumption, this link has not been sufficiently quantified under conditions of severe water scarcity. This study combines the Tapio decoupling model with water footprint analysis to assess agricultural water-use dynamics across Iran’s diverse bioclimatic zones over the period 2009–2022. By distinguishing between green water (rainfall) and blue water (surface and groundwater), a more precise understanding of the drivers of water-use efficiency is provided. The results reveal significant spatial heterogeneity in decoupling patterns. Northern semi-humid provinces, particularly Mazandaran, exhibit favorable decoupling trends due to the dominance of green water consumption (green-to-blue water ratio greater than 1), which reduces pressure on groundwater resources. Potato production in Mazandaran achieved strong decoupling(where the decoupling index falls between negative infinity and zero, (:-infty:) < DI < 0) in 57.1% of the study period. Similar patterns are observed for onion and wheat in hyper-arid provinces such as Hormozgan and Yazd, with Yazd showing strong decoupling in 71.4% of the period. The Decoupling Stability Index further indicates that regions facing severe climatic constraints tend to exhibit relatively greater stability in decoupling patterns, reflecting adaptation to ecological limits. In contrast, water-abundant regions have experienced weak water governance due to the unsustainable expansion of agricultural land. Khuzestan, Mazandaran, and Fars provinces, with DSI values of 0.26, 0.22, and 0.21 in wheat production, respectively, are in an unfavorable stability condition, posing potential risks to long-term food security. While Fars and Yazd show instability in potato and onion production, respectively, Sistan and Baluchestan and Hormozgan emerge as more stable alternatives. These findings support a multidimensional policy framework that emphasizes the strategic reallocation of cropping patterns toward more sustainable regions—an approach that can reduce pressure on depleted aquifers while maintaining national agricultural output.