A Wind Tunnel Simulation Study On The Influence Of Moisture On The Wind Erosion Resistance Of Aeolian Sandy Soil

Soil wind erosion refers to the process of soil and its parent material being separated from the surface by wind,and then transported to other areas by the process of separation and transporting,so as to lose the topsoil.Severe soil wind erosion not only takes away most of the surface particulate matter,causes the loss of fine particulate matter in soil,but also causes the soil fertility and land productivity decline,reduce crop yield,affect the regional agricultural development level,and hinder the sustainable development of the region's social economy and environment.At the same time,soil wind erosion also provides some material sources for dust storms and air pollution,which is harmful to people's physical health and life travel.The experimental results concluded by different researchers are quite comparable in the past research work,mainly because the soil types,experimental methods,experimental process,experimental equipment used in the test has differences.At the same time,the scope of the water content in their experiments is quite different,and the experimental results also have a difference.Furthermore,soil moisture is one of the important factors affecting soil wind erosion.The loss of soil moisture on the wind erosion experiment in wet sand can not be ignored,because the wind erosion of wet sand is a simultaneous process of water drying and soil erosion.Therefore,this wind tunnel experiment is designed 5groups of wind speed and 6 groups of water contentwith aeolian sandy soil inTengger Desertto understand the resistance of wet sand moisture to wind erosion more comprehensively.And here are themain experimental results,(1)The experiment of wind erosion of moist sand shows that power function between the wind erosion rate and water content is the negative power function relationshipwith-2under the same wind velocity.The greater the water content is,the smaller the soil wind erosion rate loses,and the variation of wind erosion rate decreases along with the increase of water content,and gradually becomes stable.(2)Furthermore,the water drying process of sand surface and the process of wind erosion are concomitant in the process of erosion of wet sand,and the loss of soil moisture on the wind erosion experiment in wet sand can not be ignored.When the wind speed is lower than the threshold wind velocitywith moisture content,the loss of sample weight is mainly caused by the water evaporation.However,when the wind speed is greater than the threshold wind velocitywith moisture content,the loss of sample weight mainly covers water loss and sand loss,wherethe loss of water content is mainly in the water evaporation and wind erosion in which water attached to the surface of the sand is carried along with the sand.(3)Under the precondition of the same water content,the relationship between moisture loss rateand wind speed can be described by the positive power function.The greater the wind speed becomes,the greater the moisture loss rate gets.However,under different wind speed conditions,the relationship between moisture loss rateand water content is different.In the case of low wind speed with 7 m/s and 9 m/s,the relationship between moisture loss rate and water content is roughly the positive power function.Under the wind speed conditions of 11m/s,13m/s and 15m/s,the relationship between moisture loss rateand water content is negative power function.(4)According to the results of wet sand critical start time experiment,we can describe the relationship as a positive power function between critical start timeand moisture.The greater the moisture content becomes,the longer the wind resisting time of wet sand gets,the more the time of the start of sand is postponed.The water content of 1.5%by weight is a dividing point,when the moisture content is less than 1.5%,the wet sand particles are basically powerless to resist wind erosion,and the grain of sand will quickly become dry and be eroded.However,when the moisture content is greater than 1.5%,the critical start time of sand erosion is obviously prolonged with the increase of water content.