Abstract:
To investigate the activation effect of water-retaining agent on soil seed bank in alpine sandy land in the upper reaches of the Yellow River, natural grassland, mild sandy land, moderate sandy land, severe sandy land, and extremely severe sandy land in Zoige were taken as the research objects, and the species composition and life form were analyzed. By enclousing the sample plots (moderate sandy land, severe sandy land and extremely severe sandy land), and applying different amounts of water retaining agent on the enclosed plots, the changes in the number of sprout species, plant number, plant biomass and community coverage under different water-retaining agent dosages were studied. The results showed that: (1) A total of 26 plant seeds were counted in the alpine sandy land in the upper reaches of the Yellow River in Sichuan, all of which were herbaceous plants, indicating that the families, genera, and species of seeds in this region were relatively concentrated, and the species composition type was single. (2) With the increase of the application amount of water-retaining agent, the number of herbaceous plant species and plants growing in moderate sandy areas was significantly higher than that of the control. The maximum number of germination species and the maximum germination species were reached when 0.25 kg·m
−2 water-retaining agent was applied. The number of plants in the treatment group with water-retaining agent in severe and extremely severe sandy land was significantly higher than that in the control group. With the increase of water-retaining agent applicaiton, the number of plants first increased and then decreased, and the number of seedlings reached the peak when the application amount was 0.25kg·m
−2. (3) In terms of the biomass and coverage of herbaceous plant communities in the sample plot, the biomass and coverage of plants in the application of water retaining agents were generally higher than those in the control plot. Except for the extremely severe sandy land, the biomass and coverage of moderate and severe sandy land reached the maximum when the application rate of 0.25 kg·m
−2, and then gradually decreased. In the activation experiment of soil seed bank in alpine sandy land, the amount of water-retaining agent was 0.25 kg·m
−2, which could meet the germination and growth of plant seeds. Further increasing the application amount of water-retaining agent had no significant effect on the increase of plant biomass, but may actually decreased it. According to the germination of soil seed bank species under the condition of water-retaining agent treatment, combined with the original vegetation in the study area,
Carex setschwanensis,
Leymus secalinus,
Festuca ovina,
Kengyilia rigidula,
Poa pratensis,
C. capillifolia, and
C. sinosupina could be used as reference species for ecological restoration in the study area.