Economic performance of FAO-56 crop coefficient and Allen & Pereira approaches for irrigation scheduling in super-high-density olive orchards

Increasing pressure on water resources in Mediterranean agriculture requires irrigation scheduling strategies that optimize both water-use efficiency and farm profitability. While the FAO-56 crop coefficient approach is the most widely used method for estimating crop water requirements, the Allen & Pereira approach offers a more dynamic and less empirical alternative that may be particularly suitable for automated irrigation management. This study evaluates the economic performance of these two irrigation scheduling approaches in a super-high-density ‘Arbequina’ olive orchard under commercial field conditions in southern Spain during the 2023 and 2024 growing seasons. Productive, water-use, and economic indicators were calculated, including revenues, production costs, economic margins, profit, and economic water productivity. In addition, a sensitivity analysis was conducted to assess the effects of increasing water prices and the automation of irrigation scheduling through the Isadora + decision-support system. The Allen & Pereira approach generated significantly higher irrigation, labour, and total production costs due to its greater estimated irrigation requirements and management complexity. However, no significant differences were observed between approaches in yield, revenue, gross margin, net margin, profit, or economic water productivity. Sensitivity analysis showed that economic differences between methodologies became significant only under high water-price scenarios (> €0.80 m⁻³). Furthermore, automation through Isadora + markedly reduced management costs and virtually eliminated the economic differences between methodologies. These results indicate that irrigation scheduling profitability depends more on the economic context than on the estimation method itself and highlight the potential of digital decision-support systems to facilitate the adoption of advanced irrigation scheduling approaches without compromising farm profitability.