The Coupling Effects of Using Coal Fly-Ash and Bio-Inoculant for Rehabilitation of Disturbed Biocrusts in Active Sand Dunes

Active wind-borne sand dunes, which lead to covering of fertile soils and agricultural fields, are one of the main problems in desertified lands worldwide, and stabilizing them poses a significant challenge. Such sand dunes may be naturally stabilized by biocrusts (biological soil crusts). One of the main restraints of biocrust development is the typical lack of fine particles in sand dunes. A possible artificial source of fine particles is coal fly-ash, which is the by-product of power stations and comprises of particles having a diameter of less than 100 µm. This study tested the influence of the coupling effects of coal fly-ash and bio-inoculant of filamentous cyanobacteria, isolated from natural stabilized sand dunes nearby, on the soil surface of active sands for increasing resistance to wind erosion. Boundary-layer wind tunnel experiments were conducted in experimental plots within a greenhouse for examining the effects of adding coal fly-ash and bio-inoculant to active sands. The biocrust development was evaluated via several physical and bio-physiological variables. In all the physical measurements and the bio-physiological variables, the treatment of “sand + inoculum + coal fly-ash” showed significant differences from the “sand-control”. The combination led to the best results of surface stabilization in boundary-layer wind tunnel experiments, with the lowest sand fluxes. The filamentous cyanobacteria use the fine particles of the coal fly-ash as bridges for growing toward and adhering to the large sand particles. The cumulative effects of biocrusts and coal fly-ash enhance soil surface stabilization and may allow long-term sustainability.