Seedling Raising and Growth Regulation of Picea mongolica in Arid Desert Areas

Taking seeds annual seedlings of Picea mongolica for test,effect of whether shading or not,different sand-covering depths on their seedlings' emergence rate and conservation rate was studied.Result shows: during the period from seedling emergency to wintering,conservation rate of seedlings of Picea mongolica is 69.04% 17.35% respectively with without shading.The optimum sand-covering depth for seedling raising through direct seeding is 0.5 cm.The seedlings' annual growing regulation indicates seedlings' ground diameter height growth are almost the same.The fast-growing period for height growth is in June,while that for ground diameter is from June 20,both of them become stable in July,and stop in August.During the growing period,both the dry-weight percentages of underground part and above-ground part are continuously increasing.The regression analysis shows the regression equation of the accumulated dry-weight is Y=0.000 2x-8.522 3 for underground part,and Y=-1-0.6x2+0.092 9x-1 877.4 for above-ground part.Correlation analysis reveals that the lowest temperature,soil temperature of 20 cm,15 cm and 10 cm are the key environmental factors effecting the growths of ground diameter height.