A study on grassland biomass and their relationships with meteorological factors in the northern slopes of the Mountains Qilian

Based on grassland biomass field investigation and synchronous meteorological data in 2004;we estimated grassland biomass and evaluated the relationships between grassland biomass and meteorological factors in the northern slopes of the Mountains Qilian.The results indicated that the total grassland biomass was estimated to be 490.4 g/m2.The average above ground and below ground biomass were estimated as 42.1 and 448.3 g/m2 respectively.The vegetation coverage had a prominently positive exponent correlation with biomass and soil moisture content of 0~20 cm(P0.05).It implied that biomass and soil moisture content of 0~20 cm significantly increased with the increase of vegetation coverage.Biomass was positively correlated with precipitation and relative humidity and negatively correlated with air temperature,soil temperature and aridity index.However,the relationships among all of them did not reach the level of significance(P0.05).The biomass was significantly positively correlated with soil moisture content(P0.05).Soil moisture content is the key factor influencing biomass in the northern slopes of the Mountains Qilian.