Study On The Benefits Of Sand And Sand Resistance Of Single Shrub In Ulan Buh Desert

Vegetation measures to control desertification have the most ideal effect on wind erosion control and treatment.In the past,there is a lack of previous research which can directly reflect the benefits of wind and sand resistance of a single vegetation.In response to this problem,this research selected typical single shrub in Ulan Buh desert,using wind tunnel test and laboratory analysis test methods,combined with the determination results of morphological indicators of a single shrub,A detailed study was carried out on the three-dimensional wind speed flow field,sediment transport,sand particle size change and sand erosion characteristics after a single shrub in winter.The size and range of benefit indexes of wind and sand resistance of each shrub were compared and analyzed.In order to provide a theoretical basis for the construction of wind-proof and sand-fixing system in sandy areas.Draw the following conclusions:(1)The height of non-obvious trunk shrubs is smaller than that of obvious trunk shrubs,but the crown width of non-obvious trunk shrubs is larger than that of obvious trunk shrubs.Moreover,the structure of non-obvious trunk shrubs can remain dense when there are no leaves,although the branch length of obvious trunk shrubs is longer,but the growth trend is generally extended upward,while the number of branches of no obvious trunk shrubs is shorter,but the branches are dense and extend to both sides.(2)By comparing the changes of wind speed after 6 kinds of shrubs,it was found that the variation trend of wind speed profile after single shrub was not consistent with that of the control observation point,and there was no obvious change of wind speed profile after trunk shrubs increased at first and then decreased.However,the wind speed profile of the main shrubs decreased at first and then increased and then decreased.It is also found that the advantage of obvious trunk shrubs compared with non-obvious trunk shrubs is that it has a greater effect on the average reduction of wind speed and a wide range of influence.However,there was no obvious effect of trunk shrubs on the decrease of local wind speed.(3)Under the condition of three kinds of wind speed,the amount of sediment transport decreased with the increase of height,and the sediment inhibition benefit of 6 kinds of shrubs decreased with the increase of wind speed.It was also found that the sand inhibition effect of non-obvious trunk shrubs on near-surface was higher than that of obvious trunk shrubs.(4)The distribution areas of four particle size volume percentage contents of sand particles after different individual plants are different,and there are obvious differences in sand particle size percentage content between main shrubs and non-obvious main shrubs.It is concluded that the difference of sand particle size distribution after shrubs is related to the degree of decrease of wind kinetic energy,and the branch growth and length of shrubs will lead to the variation range of sand particle size volume percentage content.(5)There were significant differences in the effects of 6 kinds of shrubs on the surface morphology,among which the surface morphology changed more obviously without obvious trunk shrubs,and the accumulation of sand particles was more obvious.