A framework for assessing the circular economy potential in the water and agriculture sectors in Türkiye through the water-energy-food-ecosystem nexus

The growing need for agricultural production and the consequences of climate change necessitate new paradigms for sustainable resource management such as the Water-Energy-Food-Ecosystem (WEFE) nexus and the circular economy approach. The WEFE nexus promotes a holistic perspective to improve resource management and economic outcomes by emphasizing the interconnectivity of its components. The circular economy framework complements the WEFE Nexus by promoting the efficient use and reuse of resources across its interconnected components. This study proposes an integrated framework for preliminary assessments of water and agriculture sectoral potentials in water reuse and bioenergy production at a macro scale. This framework includes priority assessments using multidimensional criteria through the developed Circular Agriculture Priority Assessment (CAPA) index, which provide actionable insights targeted policies, strategic investments, and research to provide water, food, energy security and maintaining of ecosystem health in Türkiye. The results indicate that Türkiye's annual resources include 22.5 million tons of crop residue, 93.8 million tons of animal manure, and 2594 hm³ of urban wastewater, which could meet 10 % of agricultural water needs through reuse and produce 12,908,772 MWh of bioenergy, covering 4.16 % of residential electricity demand. However, only 14.6 % of this energy potential is currently exploited. The CAPA index highlights certain provinces for targeted policies, strategic investments, and research initiatives. By providing a multidimensional evaluation of circular agriculture strategies within the WEFE nexus framework, this research contributes to advancing sustainable resource security and improving decision-making in agricultural production systems.