Abstract Olive crops cover a substantial area of agricultural land, particularly in dry areas with a high desertification risk, where their understory represent an important room for plant communities. Their management is therefore essential for the maintenance of the complex functions and services the vegetation provides in these agroecosystems. In southern Italy (Apulia), we selected conventionally managed and organic olive plots. The organic plots had never been ploughed for more than ten years. We compared soil properties, the species and functional trait composition of the plant community in the understory, and intraspecific trait variability (ITV) of five dominant species as an indicator of the stress source for plants. Under the organic management, the plant community had a higher cover, with strong dominance of Avena fatua , and was overall dominated by species with a higher specific leaf area, and the soil had a higher C content, which reduced the level of desertification. ITV generally showed lower environmental stress for plants in organic plots. They had higher stature, higher SLA, lower leaf area, and lower leaf mass, but – unexpectedly – they also had a higher leaf dry matter content (LDMC). Absence of ploughing of the olive plots supported the formation of an understory with high cover, where traits suitable for between-plant competition rather were more common than those for drought stress. This also promoted soil formation through carbon accumulation. Organic farming therefore seems to be a suitable option for lowering the desertification risk of olive cultures/plantations.
Migliorino et al. (Fri,) studied this question.