Effects of Ornamental Plant Potentilla fruticosa on Soil Enzyme Activity in Gangue Mountain Under Different Planting Patterns

This study investigated the effects of Potentilla fruticosa planting on plant community succession in a spoil heap, analyzed changes in soil enzyme activities under different planting methods, and explored the relationships between soil enzyme activities and plant community diversity across these planting approaches. This experiment selected Potentilla fruticosa planted under different restoration modes (covered with soil, covered with straw curtain, not covered) in Shuanglonggou gangue Mountain, Tianzhu County, Gansu Province, as the research object. The growth status and activities of soil urease, alkaline phosphatase, catalase and sucrase and their correlation were measured in different repair modes in the untreated waste rock (CK). The results showed that (1) the Simpson dominance index and Pielou evenness index decreased to a certain extent under the condition of plant community analysis; Shannon diversity index decreased in the case of curtain covering, but increased in the other two treatments. The richness index of Margalef increased to some extent, and reached the maximum when the curtain was covered. (2) The activity of soil urease and alkaline phosphatase was the lowest in the plots covered by straw curtain, and the activity was 104.4 μg/d/g and 334.5 μg/d/g, respectively. (3) The change in soil catalase activity was not obvious with the increase in soil depth, and the catalase activity in deep soil reached the maximum of 945.3 μg/d/g in the mulch soil sample. (4) The planting of golden dew had a certain effect on the activity of sucrase in shallow soil, and the maximum sucrase activity reached 15.3 μg/d/g under the condition that the planting of Potentilla fruticosa was not covered. (5) Soil urease activity and soil alkaline phosphatase activity were significantly positively correlated with plant community diversity index, while soil catalase activity and soil sucrase activity were negatively correlated with plant community diversity. (6) The total nitrogen content in the soil shows a significant positive correlation with soil urease activity. While soil alkaline phosphatase activity is significantly negatively correlated with soil moisture content, it shows a highly significant positive correlation with soil total nitrogen content. Furthermore, soil sucrase activity demonstrates a highly significant positive correlation with soil bulk density and soil available phosphorus content. To sum up, the planting of golden plum can promote the ecological restoration of gangue mountain soil, and provide a theoretical and scientific basis for ecological restoration and soil quality improvement in the Qilian Mountain mining area.