Abstract:oil algae in surface crust of desert in Shapotou were identified and studied over a 10-month period(from May 1991 to February 1992 ). The results showed that 5 genera ofCyanophyta, 6 genera of Chlorophyta and 2 genera of Bacillariophyta occurred at this site. The average algal biomass in soil was 8. 117×10 ̄4 cells/g dry soi. Meanwhile, the physicaland chemical properties of soil in crust were analysed, which included pH, water- soluablecations(K ̄+, Na ̄+, Ca ̄(2+), Mg ̄(2+)). moisture ,electric conductivit...