Selected Nitrogen and Phosphorus Fertilizer Applications Affect Seed Yield, Seed Yield Components and Roots of Elymus sibiricus

The split-plot experiment was designed to study the effects of different nitrogen and phosphorus application rates on seed yield,yield components and root growth in different growing stages of Elymus sibiricus in Hebei Province.Results indicated that nitrogen fertilizer application affected thousand-seed weight significantly(P0.05).Seed yield reached the highest rate of 592.26 kg·hm-2 with 90 kg N·hm-2 nitrogen fertilizer application.When the phosphorus fertilizer application was 90 kg P·hm-2,seed yield reached the highest rate of 680.61 kg·hm-2.The phosphorus fertilizer improved seed yield by affecting the amount of tillers per unit area,fertile tillers per unit area and spikelets per inflorescence.Without nitrogen and phosphorus fertilizer application,both total length and surface area of root are high while increasing nitrogen and phosphorus fertilizer applications initially decreased then increased both total length and surface area of root initial.Nitrogen fertilizer alone had no significant affect for average root diameter.Root growth was faster from seedling establishment to heading stage and reached its peak in seed maturation stage.