Growth Characteristics and Ecological Value Of Olea Europaea Cultivars in Abandoned Mine Slags

Mine ecological restoration is an important means of improving the ecological environment of abandoned mining areas, and the selection and configuration of plant species plays a critical role in the restoration outcomes. This study aims to investigate the effect of mine slags of different types on the growth performance and survival rate of Olea Europaea cultivars, providing a scientific basis for mine ecological restoration. The results indicated that there were significant differences in the physicochemical properties of the mining soils: clay slag had a near-neutral pH (6.856), with an organic matter content of 13.848 g·kg⁻¹; In comparison, the gravel slag was acidic (pH 5.678) ,with a slightly higher organic matter content (16.481 g·kg⁻¹). However, the heavy metal content (e.g., mercury, arsenic, chromium, cadmium, and lead) in gravel slag was generally higher than that in clay, which probably affected the plant growth and ecological restoration negatively. The growth performance of different cultivars varied significantly, ‘Arbequina’ showing the best performance with seedling height (108.67 cm), total growth (58.67 cm) and crown width (92 cm, east-west length, 85 cm, south-north length), thus it could be a primary restoration species for high-erosion-risk areas, ‘Arbosana’ and ‘Koroneiki’ being supplementary. Additionally, the slag type significantly affected the survival rates of cultivars: the survival rate of ‘Arbosana’ was 80.60% in clay slag and 89.312% in gravel slag, that of ‘Arbequina’ was 82.60%, 80.03%, that of ‘Arbequina’ ‘Koroneiki’ was 82.70%, 83.08%, respectively. In conclusion, O. Europaea L. cultivars demonstrates advantageous performance in mine restoration and are suitable as primary restoration species, while ‘Koroneiki’ could be identified as a supplementary cultivar. The effectiveness of mine ecological restoration can be significantly improved by optimizing zonal planting strategies and enhancing management measures, offering a feasible solution for vegetation recovery in similar mining areas.