Study has been conducted on the vertical distribution of soil microorganism biomass in
stabilized sand dune of the Hobq
Desert, Inner Mongolia, China. The biomass and number of different microbial groups, enzymic activities and fertility factors ( organic matter, total N and P ) in sand dunes were determined.The results showed, the microbial biomass in
stabilized sand dune were more than that of flowing sand dune, total microbial biomass were highest in biological crust of stabilized sand dune. The
vertical distribution of different microbial groups were various, the order of vertical distribution in biomass of bacteria were 0～ 0.5 cm(biological crust)>0.5～10 cm>60～70 cm>30～40 cm>150～160 cm, and the order of biomass showed the aerophile bacteria> spore\|forming bacteria>anaerophile bacteria, the order of vertical distribution in biomass of filamentous microorganisms (fungi and actinomyces) were 0～0.5 cm(biological crust)>0.5～10 cm>30～40 cm>60～70 cm>150～160 cm, the biomass was decreased with depth. Total biomass of soil microorganisms in 0～10 cm was more than other soil layers, their biomass ratio between the stabilized and flowing sand dunes in 0～10 cm showed that bacteria were 4.7 times and filamentous microorganisms were 2.0 times. There are less gap in biomass than in number between bacteria and filamentous microorganisms.\;The vertical distribution of the microorganisms and their activities in sand dunes were related to soil fertility factors.