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Procucing sufficient shrub biomass to improved soil fertility without compromising crop yield in simultaneous agroforestry system is a challenge in semi-arid conditions due to resource competitions, particularly moisture. However, manipulation of planting time and spacing of shrub components in relay intercropping system may minimize competition and improve crops yields; but little information is available on this approach. This Study assessed effects of these treatments on Tephrosia biomass yield and maize yield after months at Gairo using a split-plot experiment with planting time (0, 2 and 4 weeks after maize) and intra-row spacing of Tephrosia vogelii (0, 30, 60 and 90 cm) as main and minor plot factors, respectively. For each level of spacing, monoculture plots of Tephrosia were established for evaluating maize effects on shrub yield. After eleven months, Tephrosia biomass in monoculture plots was 2-6 times higher than relay-intercropped plots possibly due to inter-species competitions. During this time, monoculture plots were superior to relay-intercropped plots in terms of mineral nitrogen and Tephrosia treatments improved soil organic carbon and mineral nitrogen contents over sole maize. Relay intercropping without fertilizations improved maize yields percent over control in second and third seasons, indicating facilitation effects of the shrub component. The study concludes that appropriate design of Tephrosia-maize relay intercropping may enhance sustainable maize production in land-scarce semi-arid areas.