In dryland agroforestry systems, large-scale afforestation for ecological restoration often compromises groundwater sustainability, yet the roles of tree species traits (e.g., rooting depth) and soil-vegetation interactions remains unclear. We conducted a field study on the Loess Plateau, comparing 14 deep-rooted afforestation species (13 trees, 1 shrub) with adjacent shallow-rooted crops (maize, wheat, millet, etc.) across 32 paired sites. Using soil water profiling, root mapping, and tritium tracing, we found that deep rooting (4.8-28 m) reduced soil water storage by 0-2131 mm and groundwater recharge by at least 67.2 % compared to shallow-rooted vegetation. Rooting depth explained 72 % of recharge variation, outperforming climate and soil factors. Moreover, the adverse effect of rooting depth on recharge was strongly modulated by soil texture, as coarser-textured soils weaken this impact by enhancing deep percolation. These findings provide a scientific basis for selecting lowwater-demand tree species (e.g., shallow-rooted Ziziphus jujuba) to maintain groundwater recharge in dryland agroforestry systems. Our results quantify the trade-off between afforestation goals and groundwater security, offering actionable insights for climate-smart land-use planning.