Using soil seed bank in summer and previous autumn to restore vegetation in arid mining area

Objective Based on the actual situation of arid mining area in western China, this study explored the availability and constraints of soil seed bank in topsoil resources in the area, selected effective utilization models, and provided theoretical basis and technical reference for vegetation restoration in mining area.

Method The topsoil in the low-disturbance area around the Xinxing Mining Area in Wuhai City, Inner Mongolia of northern China was stripped in October of the previous year (autumn) and June of the current year (summer), and three factors including soil thickness, reseeding amount and daily irrigation amount were used, three horizontal orthogonal experiments were conducted to study the effects of soil seed bank germination in topsoil in different seasons, and combined with ecological and economic benefits, a combination of technologies suitable for vegetation restoration in arid mining area was selected.

Result (1) The number of plants germinated in the soil seed bank in October was (83.72 ± 10.88) plant/m², and a total of 20 species appeared. The number of plants germinated in the soil seed bank in June was (44.83 ± 8.96) plant/m², and a total of 13 species appeared. The soil seed bank density and species richness in autumn were higher than those in summer soil seed bank. (2) Irrigation had the most important impact on soil seed bank germination in autumn, followed by soil covering thickness, and finally reseeding. The three factors had basically the same impact on soil seed bank germination in summer. (3) The soil thickness factor had a significant impact on vegetation coverage and community height species richness of the two groups of soil seed bank (P < 0.05). The amount of irrigation had a significant impact on the number of plants germinated in two groups of soil seed bank, vegetation coverage and community height (P < 0.05). In both sets of trials, the reseeding factors did not simultaneously produce significantly different indicators.

Conclusion The optimal combination of implementation plans for vegetation restoration in dumpsites in arid mining areas is: using topsoil stripped off in autumn, with a covering soil thickness of 2 cm, a reseeding amount of 50 grain/m², and a daily irrigation volume of 2 L/m². This conclusion can provide technical reference for future vegetation restoration in mining area.