Comparative assessment of agroforestry performances between pea and barley intercropping with olive tree under Mediterranean conditions

Olive-based agroforestry could provide a sustainable solution to improving agricultural productivity and environmental conservation, particularly through intercropping cereal and legume crops with olive trees. However, the deep assessment of agro-physiological indicators between intercropped forage legumes and cereals with olive trees is poorly documented in the literature. The aim of this field research was to assess the performance of olive-based agroforestry systems by analyzing how the main agro-physiological indicators change among two contrasting intercropping arrangements of forage and arable crops. Field trials were carried out during two contrasting growing seasons in a young olive grove under semi-arid climate. To further enhance our understanding of olive-agroforestry performance in terms of growth and yield, multiple agro-physiological parameters were measured in arable and olive monocultures, as well as in the olive-intercropping system with two contrasting intercropping arrangements of pea and barley. The results demonstrated that olive tree canopy significantly stimulated the growth of shoots and roots of intercropped barley, increasing LAI (+ 4 units), shoot dry biomass (+ 56%) and both root depth (+ 19%) and width (+ 26%), compared to barley monoculture. Olive-agroforestry also enhanced barley grain and protein yield (+ 58%) during both seasons. The agroforestry system had additional benefits in improving the vegetative growth of intercropped olive trees by increasing soil nitrogen availability. Our findings highlight also the potential benefits of intercropping olive trees with pea in improving both fruit and oil yields in olive production. Olive-based agroforestry promotes an optimized micro-climate to effectively reduce the impact of drought on intercropped barley and improves resources use by pea under optimal conditions.