Biomass allocation of Miscanthus sinensis and Panicum virgatum response to different water conditions

Energy plants are suitable to be planted in semiarid Loess plateau with huge potential production capacity. However, Loess plateau is famous as fragile ecological environment which limited production capacity as water deficit. In order to explor highyield energy plants with watersaving, the dry matter distributions of Miscanthus sinensis and Panicum virgatum under different soil moisture(75%, 55%, 35% of field moisture capacity) were studied. The results showed that the root biomass, shoot biomass and total biomass were significantly affected (P0.05) by both moisture contents and species. The biomass of M. sinensis was significantly higher (P0.05) than that of P. virgatum for all treatments. The biomass of both species significantly decreased (P0.05) with the decrease of soil moisture content. The soil moisture contents had significant effects (P0.05) on rootshoot ratio of P. virgatum whereas it has little effects on that of M. sinensis. With the lower moisture content, P. virgatum could strengthen the absorption of water and nutrients with more root number and higher rootshoot ratio. For root biomass, shoot biomass and total biomass of the both energy plants, there was no significant difference between control and the treatments with 75% and 55% of soil moisture capacity. M. sinensis and P. virgatum could use water more efficiently under 55% soil moisture capacity.