The study on dynamics of aboveground biomass and nutrients of perennial sowing grassland in a Grain for Green area

Dynamic of the aboveground biomass and nutrients of perennial grassland sown in different time were measured in a Grain for Green area from July 15 to September 18,2008. The result showed that the aboveground biomass initially increased as the plants growing and then dropped during experimental stage, the maximum appeared from August 23 to September 18. The contents of crude protein, crude fat and crude ash decreased, and the contents of crude fiber increased from July 17 to September 18.