**3.4 Excellent herbaceous plants tolerant to sand burial**

Sand materials accumulate in the area along the Qinghai-Tibet Railway with severe sand damage. Ordinary plant species are easily buried by sand, causing vegetation restoration to fail. Sand burial resistance test was carried out on five native herbaceous plants: *Lolium perenne*, *Festuca sinensi*, *Elymus breviaristatus*, *Elymus nutans* and *Poa crymophila* [12].

The depth of sand burial had a significant effect on the plant height and root length of 5 grasses. At the same time, seeds with a high thousand-grain weight have a high germination rate. At a burial depth of 0–6 cm, the plant height of *L. perenne* showed an upward trend and then a downward trend, while the root length showed an increasing trend. The maximum plant height and maximum root length appeared at the buried depth of 4 cm and 6 cm. The plant height and root length of *F. sinensi*, *E. breviaristatus* and *E. nutans* all showed a trend of first increasing and then decreasing. For the maximum plant height and root length, *F. sinensi* appeared at 1 cm and 2 cm burial depths, *E. breviaristatus* appeared at 3 cm burial depths, and *E. nutans* appeared at 2 cm and 3 cm burial depths. However, *P. crymophila* failed to emerge at a depth of more than 3 cm in the sand. The maximum plant height appears at a burial depth of 0–1 cm, and the maximum root length appears at a burial depth of 2 cm.

Therefore, in the process of vegetation restoration and reconstruction, seeds with good quality and high thousand-grain weight should be selected for the restoration of moderate sand-buried vegetation with a thickness of 1–3 cm in order to increase the rate of seed emergence and increase the rate of seedling colonization. At the same time, *L. perenne*, *F. sinensi*, *E. breviaristatus* and *E. nutans* can be used for vegetation restoration in areas with severe sand damage along the line. *Poa crymophila* can be used for vegetation restoration in mild sand-damaged areas where the accumulation rate of sand material is low.
