Volume 11 Article informations Assessment of radial variation of soil properties in an olive tree – barley/common vetch agroforestry system under low-input conditions in a Tunisian semi-arid climate after three cropping seasons Hanen Guesmi, Hamouda Aichil, Ghayda Bendhafer, Youssef Fouad, Safia Menasseri, Hatem Chaar Abstract Tree-based intercropping system is a great example of agroecology that a growing body of research has suggested as a solution to several environmental problems, among others, losing soil fertility. We aimed to assess the effect of intercrops and the distance from the tree canopy on active carbon, soil organic carbon, total nitrogen, C/N ratio and available phosphorus in samples collected at 0-30 cm layer in an olive tree – barley/common vetch agroforestry system. In this experiment, the measured soil parameters varied significantly and linearly with distance from tree canopy except for C/N ratio. The highest means were recorded near by the tree olive canopy (0m). In the middle (4m) of the interrows, the studied soil parameters recorded the lowest contents. With vetch and barley-vetch intercrops soil carbon and soil measured nutrients recorded the highest means compared to barley and fallow. We conclude that the tree component in agro-ecosystems, sowing nearby tree rows did not alter soil nutrient availability mainly with legume and mixture of legume and grass species. In a short scale time intercrops showed no significant changes in soil quality mainly with barley. Thus the choice of intercrops and the continuity of TBI system practice remain impotent to show significant change in a long-term scale.