Potentials of the microalgae inoculant in restoration of biological soil crusts to combat desertification

The world is presently faced to the many calamities, mainly the increased and rapidly developing environmental changes, soil degradation as an example of such environmental problems which is correlated with the destructive effects of the sandstorms. Biological soil crust (BSC), a main component of soil, has various environmental functions including reduction in the erosion by increasing soil stability and providing a sanctuary for the growth of the taxa and vascular plants communities. Destruction of BSC, which naturally can be recovered slowly in a long time processes, contributes to the desertification and other environmental catastrophes. Therefore, accelerating the BSC recovery both the quality and the quantity of the crust development, especially in the desert areas, is of the prime interest. Recent advances in the BSC restoration have provided an immense potential for emulating the natural restoration methods mainly through providing soils with inoculant. This paper reviews the present restoration-based procedures for the biological soil crust restoration practice. The main landmarks are presented and highlighted including strain(s) selection and development, mass biomass production, inoculum preparation, soil inoculation, soil augmentation, nurseries, and crust succession monitoring and control. The review also introduces several successful case studies in the USA and the Republic of China. Thereafter, the paper briefly documents the future directions of the research and technologies. Development of a restoration system through the application of the microalgae inoculant is an encouraging aspect for accelerating the BSC recovery of the arid and semi-arid areas. However, further researches will help to establish and consolidate the potential of the microalgae cells and their application in desertification programs in large scales and in accordance with principles and requirements mandated by economic standards.