Activating effect of different precipitation conditions on a soil seed bank in an arid mining area

In recent years, with the gradual westward shift of the national coal development industry, increasing attention has been paid to the ecological restoration of arid desert mining areas. However, under the background of water scarcity in arid mining areas, research on the activation of soil seed banks (especially persistent soil seed banks) under natural rainfall conditions is still scarce. The Xinxing open-pit coal mine in Wuhai City, Inner Mongolia, was considered as the research object. Using the method of germination test under artificial rainfall, the germination process of the persistent soil seed bank around the mining area under different rainfall gradients, and the activation effect of different daily and annual rainfall on the soil seed bank were studied. The results show that: 1) The activation effect of different daily rainfall on the soil seed bank is different. With the increase of daily rainfall, the number of activated soil seed bank species and the number of seed germination both increase first and then decrease. Among them, the number of seeds germinated by 5 mm daily rainfall is the largest. The number of species germinated in 10 mm daily rainfall is the largest. 2) Different plant seeds have different response states to different daily rainfall. Eragrostis minor and Artemisia frigida with the largest number of seed germinations can be activated in 3～20 mm daily rainfall, while seeds of shrubs such as Reaumuria songarica and Oxytropis aciphylla need to be activated above 10 mm daily rainfall. 3) Within the designed annual rainfall range, the number of activated seeds accounted from 20.67% to 68.52% of the soil seed bank's seed reserves, and the number of activated species accounted from 25.00% to 62.50% of the total number of soil seed bank species, both of which showed a trend of increasing first and then stabilizing. Under different annual rainfall gradients, the germinated species composition and community structure of the soil seed bank are significantly different.