Suksaroj T.T.Kowsuvon N.Suksaroj C.Maprasit S.Srisook A.Suriyawongpaisal W.Puttrawutichai S.Samanmit P.Namin N.Mahidol University2026-03-052026-03-052026-06-01Environmental and Sustainability Indicators Vol.30 (2026)https://repository.li.mahidol.ac.th/handle/123456789/115569This research develops a water-centric nexus assessment framework for Thailand's major crops: rice, sugarcane, and cassava, within shared cultivation areas. The framework examines interaction among water use, agricultural productivity, and economic performance, positioning water as the central analytical dimension. A 10-year monthly dataset (2013–2022) from official sources was examined, and farmer interviews confirmed the relevance of variables, cost structures, and adaptive capacity. Applying a system-thinking approach using VENSIM software to construct causal loop diagrams and perform scenario-based analyses rather than full dynamic simulations. The framework integrates three normalized components: water mass productivity, economic water productivity, and water security, into a composite nexus index. Results indicate that sugarcane has the highest water productivity (0.010 tons/m³), followed by cassava (0.004 tons/m³) and rice (0.00031 tons/m³). Sugarcane also demonstrates superior economic water productivity, yielding higher profits per unit of water consumed. Sensitivity analysis reveals that expanding cultivation areas generally reduces water security; however, productivity and water-use efficiency improvements can offset these impacts up to crop-specific land-use thresholds. The sustainable annual expansion rates are estimated at 0.68% for sugarcane and 0.75% for cassava, while rice requires a 0.26% reduction in cultivated area to sustain a positive Water–Economy–Food nexus. Beyond these thresholds, the nexus turns unfavorable. Overall, the findings highlight the importance of demand-side water management, strategic crop allocation, and farmer adaptability in sustaining a stable water-centric nexus. The proposed framework provides a practical decision-support tool for integrated agricultural water management and policy development in Thailand.Environmental ScienceAgricultural and Biological SciencesArticleSCOPUS10.1016/j.indic.2026.1011932-s2.0-10503126380826659727