Experimental Study On Prevention And Control Of Wind Erosion And Dust Emission By Biological Soil Crust In Bashang Area

The Bashang area in Hebei Province is affected by the strong winds of spring and autumn.The problem of soil wind erosion and dust enission is particularly serious.In recent years,the area mainly relies on the construction of shelter forests to control related problems.Few studies have affected the effects of soil crust on soil wind erosion and dust emission.In this study,the biological soil crust was taken as the research object,and the single-factor experimental design method was used to carry out artificial cultivation of biological crust,wind tunnel experiment and field wind erosion dust verification.The results showed that:(1)The coverage and thickness of algae crust and moss crust were positively correlated with culture time.The optimal measures for short-term rapid culture of algae crust and moss crust were:2 days watering+nutrient solution treatment;long-term culture The optimal measures were 2 days of watering+no nutrient solution treatment;nutrient solution had the greatest effect on biological crust development within 30-60 days of culture period,and water had the greatest effect on biological crust development within 60-90 days of culture period.(2)From the aspect of wind protection,in the height range of 0-10cm,the biological crust has the most significant influence on the airflow velocity.In this height range,it shows the bare wind speed<algal crust wind speed<mossy crust wind speed,when the height>At 10cm,it is expressed as algal crust wind speed<mossy crust wind speed<bare land wind speed.The frictional wind speed of the biological crust increases with the increase of the wind speed,and the aerodynamic roughness decreases with the increase of the wind speed.The aerodynamic roughness of the algal crust is close to the bare ground when the cover degree is>50%.In terms of sand fixation,the ability of soil crust to increase sand increases with the increase of coverage.Compared with bare land,when the crust cover is>75%,the sand-fixing capacity reaches the maximum,algae crust and moss crust.The rate of wind erosion is reduced by 0.47g/m2/s and 0·38g/m2/s,respectively;(3)The particle flux of algal crust reached a minimum under the condition of 10-25%coverage,which was 2722.69mg,1990.32mg,1530.56mg and 1121.75mg,the particle fluxes reached the maximum at 50-75%coverage,7350.23mg,6489.53%,59.8.10mg and 4375.05mg.Moss crusts reached a minimum of 50-75%coverage under the condition of 50-75%coverage,which were 1250·79mg,681.05mg,286.21mg and 161.33mg respectively,and the particulate matter flux at 75-100%coverage The maximum values were reached,which were 2954.86 mg,2102.02 mg,1458.50 mg,and 997.08 mg,respectively.Compared with bare land,the mossy crust emission flux of four kinds of particulate matter can be reduced by 2949.47mg,2206.58mg,2053.93mg and 1614.78mg,respectively.The particulate matter emission flux of algal crust increased by 454.95mg and 505.17mg respectively than bare land.,496.39 mg and 427.14 mg.