Effects of nitrogen level and harvest time on biomass yield and energy characteristics of switchgrass

The study evaluated the effects of nitrogen application level and harvest time on the productivity and energy characteristics of switchgrass in saline-alkali soil of Yellow River Delta in China. The results demonstrated that nitrogen could significantly increase the biomass of switchgrass. The highest yield of switchgrass was obtained at the fertilization of 200 kg N·ha-1(P0.01). The biomass, ash, nitrogen and lignocellulose contents of switchgrass showed a significant response to the harvest time(P0.05); As the harvest time delayed, the content of lignocelluloses increased, and it reached the highest in winter and the optimal nirtrogen level was 100 kg N·ha-1. However, the ash content and nitrogen content showed a downward trend by delaying the harvest time. Therefore, our study suggested the high quality switchgrass will be obtained when harvest in winter and with the fertilizer application of 100~150 kg N·ha-1 in the Yellow River Delta .