Plant diversity and its relationship with soil enzyme activities and nutrients under different reclamation treatments in open-pit coal mining area

The objective of this study is to investigate the variations in plant diversity and its correlation with soil enzyme activity and nutrient indexes in an open pit coal mining area under different reclamation treatments. The present study focused on the reclamation land of Hippophae rhamnoides and Amorpha fruticosa in the Hedaigou mining area as the research site. By employing various analytical methods, we investigated changes in plant diversity, differences in soil nutrient content and soil enzyme activities, as well as the significant relationships among four restoration treatments (inoculation (I), inoculation + green fertilizer (IG), inoculation + green fertilizer + weathered coal (IDG) and non-inoculation control (CK)).The results showed that the plant community structure and composition in the reclamation area were relatively simple, and the common plant species among the plots with different restoration treatments were mainly Poa annua and Elymus dahuricus. Although the whole reclamation area was still in the early stage of vegetation restoration, there were significant differences in plant diversity indices among different restoration treatments. Compared with the control treatment, the Shannon-Wiener index of Hippophae rhamnoides and Amorpha fruticosa samples under I treatment was significantly increased by 81.61% and 42.70%, respectively, and that under IDG treatment was significantly increased by 54.02% and 31.46%, respectively. Comprehensive comparison of the soil restoration effect of different reclamation treatments found that I and IDG treatment had the most significant effect on the improvement of reclamation area. The contents of organic matter and total nitrogen and the activities of urease and alkaline phosphatase in soil of treatments by inoculation and inoculation + green fertilizer + weathered coal were more than one times of those treated with control. At the same time, soil nutrients and soil enzyme activities were positively correlated with species diversity, among which organic matter, total nitrogen content, urease and phosphatase activities were the main factors affecting plant community diversity in reclamation area. In conclusion, The application of certain reclamation measures in the process of ecological restoration in coal mining areas does have a positive effect on the increase of plant diversity and land improvement, and this result can also provide more theoretical basis and scientific significance for ecological restoration in coal mining areas.