Seeking almond cultivars response to irrigation and soil-management systems using eco-physiological behaviour and its connections to productivity

Abstract

Water scarcity is the most limiting factor in many Mediterranean regions, making the implementation of sustainable irrigation and soil-management strategies essential for sustainable production. Almond (Prunus dulcis Mill.) represents the second woody crop in Andalusia (Southern Spain). This study integrates the physiological and yield responses of four almond cultivars (Marcona, Guara, Lauranne, and Marta) grown under different management strategies: two irrigation regimes [full irrigation (FI) and regulated-deficit irrigation (RDI)] and two soil-management systems [cover crop (CC) and bare soil (BS)]; during two monitoring seasons (2024–2025). The net photosynthesis (An), stomatal conductance (gsw), transpiration (E), intercellular CO2 concentration (Ci), and stem-water potential (ΨStem) were monitored throughout the three key phenological stages (vegetative growth, kernel filling, and post-harvest). At the end of each season, the yield (in-shell almonds, kernel, and single fruit weight) was measured for each treatment and cultivars. The RDI reduced irrigation volumes ~ 50% compared with FI, without significant declines in kernel yield, revealing an improvement in water productivity. The cultivar strongly influenced the physiological behaviour, since cvs. Marta and Marcona required higher gsw to reach the maximum An rates. The analysis revealed that gsw exerted the main control over An, particularly during mid-summer and kernel-filling stage, showing its key regulatory role in almond photosynthetic performance under drought conditions. In relation to the soil-management systems, CC did not affect the gas exchange activity and yield, compared with BS. Singularly, the combination of RDI x CC proved fully compatible, encouraging physiological stability without compromising almond yield. Finally, we corroborate that the cultivar selection is crucial, when coupled with RDI and vegetative soil cover, which potentially provides an effective strategy for improvement water-irrigation management and soil health, and therefore, fostering the sustainable almond cultivation in Mediterranean agroecosystems.