The facilitative effects of shrub on induced biological soil crust development and soil properties

Both planting sand-fixation vegetation and inoculation of cyanobacteria are effective pathways to form induced biological soil crusts (IBSCs) and achieve desertification reversal. Nonetheless, available information on the combination of vegetation plantation and cyanobacteria inoculation is insufficient. In the sand-fixation experimental area of Hobq Desert, IBSCs and underlying soil along two shrub canopies gradient were investigated to reveal the effects of shrub on IBSCs development and soil properties. Results showed that shrub canopy accelerated the development level of IBSC as indicated by higher crust thickness, DNA content and moss abundance under plant canopy than the surroundings. Soil under plant cover contained finer particles, higher carbon and nitrogen content, and more bioavailable dissolved organic matter (DOM). Interspaces between two plants which accounted for about 12% of the variation in soil characteristics and crust developmental indicators, might be more conducive to the growth of IBSCs and soil accumulation than other exposed microsites. Both Salix psammophila and Artemisia ordosica have a positive effect on IBSC development and soil quality. Our study indicates cyanobacteria inoculation combined with optimized sand-fixing shrub plantation might be promising in soil formation and desertification control.