The PRIME Index: Prioritization of cultivated Regions IMpacted by drought in agriculturE

The agricultural sector is particularly affected by drought events due to its direct dependency on precipitation and evapotranspiration. Droughts represent the foremost threat to food security, leading to reduced crop yields and, in severe cases, complete crop failure. A comprehensive understanding of drought is therefore essential for effective risk management and the strategic planning of water resource conservation in both the short and long term. Within the framework of the CASTLE project, this research combines the Standardized Precipitation Evapotranspiration Index (SPEI) at multiple time scales, computed from 1951 to 2024, with crop harvest data to identify Italy’s most drought exposed agricultural hotspots. By integrating these datasets, the study establishes a foundation for the development of targeted adaptation strategies for water management in the agricultural sector. We conducted an initial assessment of agricultural drought across Italy using the SPEI signal at a 6 month timescale, which highlights a significant increase in the number, duration, and intensity of drought events, indicating progressively drought-prone conditions. Building on this, we perform a crop-specific SPEI analysis over the 74-year observation period, identifying the years in which drought conditions coincided with the harvest season. The findings reveal a sharp expansion in the overall extent of drought-affected regions over the past two decades, underscoring not only an intensification and increased frequency of drought events but also a widening geographic impact. These findings are synthesized into the novel “PRIME Index,” which quantifies agricultural drought susceptibility by considering both crop area extent and crop economic value. This index enables the precise identification of regions at the highest risk of agricultural drought, providing a powerful tool for prioritizing interventions and safeguarding agricultural production in Italy.