Conclusion
An appropriate proportion of gravels in the soil can improve the
availability of soil water and promote plant growth, but the lower TN
and SOC contents in soils with 30% and 50% gravel content also limit
the plant growth. In addition, the introduced and domesticated plantsFestuca elata and Medicago sativa had better short-term
ecological restoration effects than native plants Elymus
dahuricus . However, if Festuca elata plus Elymus
dahuricus were mixed with different species and niche plants, the same
life history strategy and similar soil resource requirements would
enhance the competitiveness of plants for nutrients and water in gravel
soils. With the participation of ecologic niche plants, the ecological
factors of each component have a relatively reasonable proportion, which
can make the space complimentary. Gravel soil can increase the
availability of water and nutrients, and promote the community yield in
the short term. Therefore, in the process of ecological restoration on
the Qinghai-Tibet Plateau, TN and SOC should be added for coarse soil
textures with high gravel content, and ecologic niche plants should be
mixed to achieve an ideal ecological restoration effect.