Seasonal Dynamics of Soil Seed Bank in the Lower Reaches of Tarim River

The typical severely degraded regions due to irrational utilization of water and land in the lower reaches of Tarim River were chosen as a study area. By using the germination method in the experiment on germination of soil seed bank,the dynamics of basic characteristics,density,and species of soil seed bank were analyzed.Vegetation restoration in the areas was also discussed in terms of potential role of the soil!seed bank.Results show that without taking the effect of graze into account,seasonal dynamics of the soil seed bank is quite obvious and density and species abundance of the seed bank in March is lower than that in August.In terms of species composition,annual herbaceous plant is dominant in March and the seeds of Populus euphratica Oliv and Tamarix L almost appear in August.With the aggravated degradation,density and species abundance of the soil seed bank decrease significantly.To activate the soil seed bank is feasible theoretically for vegetation restoration in the lower reaches of Tarim River,for density and species abundance of soil seed bank is further larger than those of standing vegetation.Taking account of vegetation restoration and regeneration,our study suggests that the best time for water transferring should be from August to November.