Abstract:

To study the response of plant seedling growth to the change of precipitation and wind velocity in sandy land, we carried out simulation control experiments by artificial precipitation and wind screen reduction in 40 concrete square pools of 2 m×2 m×2 m during the period of seed germination starting in mid-April 2016. The results showed that: ① Wind velocity, precipitation and interaction of these two treatments had no significant effect on the species richness (P>0.05). The seed germination rates could be increased by 4.9% and 1.3% under the 20% wind velocity reduction and 60% precipitation increment, respectively, compared with those of controlled experiment. The species richness was increased by 7.2% under 20% reduction of wind velocity and 60% precipitation increment;②The seedling density and height fluctuated greatly under different precipitation treatments. A wind speed reduction can significantly promote seedling growth height in sandy land, especially for Salsola collina and Corispermum macrocarpum (P<0.01). Under the condition of natural wind speed, 30% precipitation increment obviously promoted the growth of seedling height, while 60% precipitation increment was contrary. Under the 20% wind velocity reduction, the growth height of Bassia dasyphylla seedlings could be greatly promoted by the 60% precipitation increment.The synergistic effects of the 40% wind velocity reduction and 30% and 60% precipitation increments resulted in a significant decrease in the growth height of the seedlings of Bassia dasyphylla, Salsola collina and Corispermum macrocarpum. ③ The effects of different wind velocity and precipitation treatments on species diversity, including the Simpson index (D), Shannon-Winner index (H) and Pielou evenness index (J), were not significant (P>0.05). In conclusion, the effect of 30% precipitation increment on the species richness during the period of seed germination was significant, wind velocity was the main factor affecting the height of plant seedlings. Under the natural conditions, the increase of seedling height was the maximum under 40% wind velocity reduction. The response of species diversity to the change of wind velocity and precipitation was not sensitive, which indicated that the community structure of the ecosystem was comparatively stable in the Horqin Sandy Land.

Key words: psammophyte, wind velocity, precipitation, seedling growth, Horqin Sandy Land