Seasonal dynamics of aboveground biomass and nutrients of Kobresia tibetica meadow in Yellow River headwater area

Seasonal nutrition dynamics of fenced and grazed Kobresia tibetica meadow in Yellow River headwater source were studied with methods of field investigation and lab analysis. The result showed that the total biomass of grazed and fenced meadow decreased from August to the next April and the natural biomass loss were 46.2% and 49.6% respectively. The natural loss rates were 5.1% from January to April and 5.9% from April to May in fenced grassland. After grazing, the factual utilization rate of grazed grassland was around 48.4% of the total biomass of fenced grassland in April, and 24.4% of that in August. The contents of crude protein and crude fat decreased from August to the next January in the grazed grassland, while the crude fiber content increased. The nutritive type of meadow was NC in summer and C in winter.