Survey on the grassland conditions and biomass in Nagqu County of Tibetan Autonomous Region

The survey on the grassland condition and 6 typical forages in Nagqu County was conducted during the growing season from May to August in 2007 by measuring the vegetation coverage, aboveground biomass, moisture contents in grasses and soil, rodent damage degree. The results showed that Kobresia tibetica was the best in terms of growth and yield. The soil moisture, proportion of poisonous grasses, rodent damage degree, grassland degradation degree and soil fertility were significantly different among sampling sites. The biomass was positively related to the precipitation, air temperature and soil temperature. The quality of K. pygmaea was better than K. tibetica and Androsace umbellata was the most poorest in terms of the contents of crude protein and crude fat.