Increasing wind erosion resistance of aeolian sandy soil by microbially induced calcium carbonate precipitation

Wind erosion of aeolian sandy soil can cause serious land degradation and other environmental problems, and thus its prevention and control is very important. However, there has not been a very effective way to prevent this severe wind erosion until now, and traditional measures such as mechanical methods, chemical sand- fixing methods, and agronomic methods also have many disadvantages. The main objective of this study is to evaluate feasibility of microbially induced calcite precipitation ( MICP) as a novel soil- strengthening technique, to cement aeolian sandy soil, and reduce wind erosion risk. For this purpose, aeolian sandy soil was cemented with Sporosarcina pasteurii through MICP technique, and the physical and mechanical properties and wind erosion resistance of cemented aeolian sandy soil were tested. The results show that wind erosion resistance of aeolian sandy soil can be effectively improved by spraying S. pasteurii solution and cementing solution ( equal concentration of urea and calcium chloride mixture) into it from the surface, and the cemented aeolian sandy soil had good wind erosion resistance. Finally, morphology of precipitated CaCO3 crystals was studied using scanning electron microscope, optical microscope, and X- ray diffraction. The calcium carbonate crystals produced in aeolian sandy soil were calcite, and the calcium carbonate crystals had polyhedral, spherical, or flower clusters crystal morphology. The results of this study demonstrate an effective way to use MICP technology to cement aeolian sandy soil and prevent wind erosion, and provide a new way for wind erosion prevention.