Key Climate Factors in Species Introduction for Ecological Reconstruction of the Dump Site of Shenhua Baorixile Open-pit Mining

Shenhua Baorixile Open-pit Mining is located in the second zone of Chinese drought-tolerant zone. In this zone, dump site ecological restoration is hard because of cold, large temperature difference between day and night, and short frost-free period. In the ecological restoration process, it is important that select the right introduction species based on local climate and site conditions. Comprehensive environment requirements of plant growth and climate characteristics of the dumping sites in the research area such as cold injury, active accumulated temperature and wind field are key factors that influence plant introduction, plant growth and seeding. Some climatic characteristics affecting plant introduction and growth were statistically analyzed by studying the climatic characte-ristics of the dump site of Shenhua Baorixile Open-pit Mining from 2011 to 2019 as well as the diversity of native plants in black clay topsoil and humus topsoil in the research area and the effective accumulated temperature of main vegetation growth. As the analysis confirmed, the annual minimum temperature in the research area was -42~-35 ℃, the average annual frost-free period was 130 days, the average annual effective accumulated temperature was 2 391.8 ℃, and the average annual effective growth days was 157.11 d; according to the growth characteristics of Kochia scoparia (L.) Schrad and Salsola collina Pall, which are mainly local plants, the evaluation index for introduced species was established, namely active accumulated temperature requirement < 2 100 ℃, minimum plant temperature tolerance < 5 ℃, perennial plant root freezing temperature < -40 ℃, germination temperature >10 ℃, and ave-rage growth period of about 90 days.