Abstract: Soil legacy effects arising from the individual or interactive impacts of environmental stressors and plant diversity on subsequent plant growth through the modification of soil properties remain poorly understood. To address this knowledge gap, a two-phase experiment (comprising a regulation phase and a feedback phase) was conducted. This study specifically examined how soil legacies generated by single or combined drought and salinity-alkalinity stresses, alongside monoculture versus mixture plantings of forage species, affect the growth and subsequent drought tolerance of maize (Zea mays L.). In the regulation phase, four common forage species were cultivated under four distinct monoculture regimes and one mixed-species treatment. These plantings were subjected to three stress conditions: drought, salinity-alkalinity, and their combination (drought + salinity-alkalinity), with the objective of screening species-specific responses to these stressors. During the subsequent feedback phase, maize was grown in the soils conditioned in the previous phase, under both well-watered and drought-stressed conditions. Key growth parameters were measured to assess legacy effects. The results revealed that under drought stress applied during the regulation phase, the mixed-species treatment yielded significantly greater aboveground and root biomass compared to the monocultures, demonstrating a clear overyielding effect. The aboveground biomass in mixtures reached 5.79 t·hm⁻², a value approaching the 5.81 t·hm⁻² observed in non-stressed monocultures, underscoring the compensatory role of species complementarity in maintaining biomass production under stress. In the feedback phase, under non-stress conditions, a significant interaction was observed between the prior plant diversity treatment and the type of stress applied during the conditioning phase, which subsequently influenced maize biomass. Under drought conditions in the feedback phase, the soil legacy derived from the mixed-species planting significantly enhanced maize aboveground biomass, root biomass, and the root-to-shoot ratio, thereby improving the crop's overall drought adaptive capacity. In summary, mixture planting fosters increased plant diversity, which shapes a more resilient soil environment. The legacy effects of this environment can effectively buffer subsequent crops, such as maize, against the detrimental impacts of abiotic stresses like drought. These findings offer valuable theoretical and practical insights for enhancing crop resilience in semi-arid regions through the optimization of planting strategies that leverage positive soil legacy effects.