Abstract:

Through the long-term positioning monitoring on aboveground vegetation and soil water contents of 0-40 cm layer in the middle Heihe River Basin from 2008 to 2016，we researched the effects of vegetation height， coverage， density and soil water variations on aboveground vegetation biomass in different desert areas， and confirmed contribution rates of different influencing factors to biomass. We hoped the result can provide the data support to ecological management of desertification in the region. The results showed that the interannual variations of biomass in Longshou desert area fluctuate greatly from 85.8 g·m^-2 to 214.6 g·m^-2. In 2015， the coverage of plants community and biomass were the largest and reached to 33.7% and 214.6 g·m^-2， respectively. The density of community had a great contribution with a rate of 27% to interannual changes of biomass. Then those of the community height and soil water content in 10-20 cm layer were also higher and up to 14%. In Xidong desert area，the interannual variations of biomass were 55.1-109.8 g·m^-2， having small fluctuation range. The community coverage， plant density and height had little effects on the interannual variations of biomass. However， the changes of soil water contents in 0-40 cm layers contributed more than 20% rates to the changes of biomass.

Key words: desert vegetation, biomass, variation characteristics, influencing factors, Heihe River Basin