A Preliminary Analysis of Irrigation Strategies Across Global Climate Zones

Increasing climate variability, more frequent droughts, and growing competition for freshwater resources amplify uncertainty in irrigation water availability and challenge sustainable agricultural water management. Addressing this uncertainty is essential for maintaining crop productivity under changing climatic conditions. This study presents a preliminary, climate-driven assessment of irrigation strategies using numerical irrigation experiments at more than ten climatically representative agricultural sites worldwide.

The site selection is based on the second level of the Köppen–Geiger climate classification, with each site representing a distinct agro-climatic zone characterized by contrasting precipitation regimes, evaporative demand, and seasonal variability. By prioritizing climatic representativeness over dense spatial coverage, the analysis enables systematic comparison of irrigation responses across a broad range of hydroclimatic conditions.

Crop growth and yield responses are simulated using the FAO AquaCrop model, which provides a robust representation of crop water productivity under water-limited conditions. AquaCrop simulations are coupled with multiple irrigation scheduling strategies implemented through the Deficit Irrigation Toolbox (DIT), an open-source probabilistic simulation–optimization framework developed in MATLAB. This integrated modeling approach explicitly accounts for climate-driven uncertainty by evaluating rainfed conditions, full irrigation, and optimized deficit irrigation strategies under stochastic weather forcing. Model outputs include irrigation water demand, yield response, and water productivity, enabling the assessment of trade-offs between production stability and water use efficiency.

The results highlight pronounced climate-dependent differences in irrigation requirements and sensitivity to water availability. In particular, the simulations indicate that deficit irrigation can reduce vulnerability to interannual water scarcity and improve water productivity in arid and semi-arid regions, while offering limited benefits in humid climates.

This preliminary analysis establishes a methodological foundation for a future global-scale assessment of irrigation strategies under uncertain water resources and supports the development of climate-adaptive irrigation management approaches.