Effects of irrigation volume and density on growth performance and above/underground biomass of Elymus nutans

Appropriate irrigation volume and density are the key factors for managing pasture. A pot experiment was carried out to determine the effect of three irrigation volumes (35%～40%, 60%～65%, and 75%～80% of saturated soil moisture) and three densities (20, 35, and 50 plants per pot) on growth performance and above/underground biomass of Elymus nutans. The results of this study showed that there was an increasing trend in the aboveground and underground biomass, tillers per plant, and root volume with increasing irrigation volume. The plant height and the ratio of aboveground biomass to underground biomass first increased and then decreased as irrigation volume increased. With the increase of plant density, tillers per plant and aboveground biomass per plant decreased, but the density had no significant effect on aboveground and underground biomass, plant height, root volume, and the ratio of aboveground biomass to underground biomass. The interaction of irrigation volume and plant density only had a significant (P < 0.05) effect on the biomass of individual plants but had no significant effect on the biomass of the plant population. These results will provide useful information for the establishment and management of E. nutans pastures in alpine pastoral areas of China.