| Due to natural and man-made reasons,China’s desert grasslands have been seriously degraded,causing harm to national economic and social development.In order to quickly restore degraded grassland vegetation and reduce the occurrence and development of soil wind erosion,planting Caragana korshinskii in degraded grassland can improve the vegetation growth environment.It is a low-cost and high-benefit method for vegetation restoration of degraded grassland.Taking Caragana korshinskii belt in Siziwang Banner of Inner Mongolia Autonomous Region as the physical model,the simulation experiment is carried out in OFDY-1.2mobile wind erosion wind tunnel of Inner Mongolia Agricultural University.With the arrangement of Caragana korshinskii belt in one row and one belt,the protective effects of Caragana korshinskii belt with different stumping height(20 cm,30 cm and 40 cm)and different porosity(35%,50% and 65%)on surface soil were studied,the influence law of Caragana korshinskii belt stumping on soil wind erosion was analyzed,and the appropriate stumping height and porosity of Caragana korshinskii belt were determined.The research conclusions are as follows:(1)Caragana korshinskii belt has the function of reducing wind speed as a whole.The change of wind speed and flow field behind the belt is complex,and acceleration zone and deceleration zone are formed locally.(2)The change of wind speed behind the Caragana belt is jointly affected by the central wind speed,the height of the Caragana belt and the degree of porosity.Under the same central wind speed and the same stumping height,the wind protection effect behind the Caragana belt is: 35% > 50% > 65%.(3)Caragana belt has different effects on the wind speed in the vertical direction.The greater the central wind speed,the greater the variation of the wind speed profile behind the Caragana korshinskii belt is.(4)For the Caragana korshinskii belt with the same stumping height,the greater the porosity value,the greater the sand collection after the belt,and the ability of Caragana korshinskii belt to resist wind erosion of surface soil is relatively weak.For the Caragana korshinskii belt with the same degree of porosity,the sand collection after the belt decreases with the increase of height,which is much less than that of the cavity experiment.The amount of sand collected behind the 30 cm and 40 cm high Caragana korshinskii belt is similar,and far less than that behind the 20 cm high Caragana korshinskii belt.(5)The height and porosity of Caragana korshinskii belt are important indicators affecting soil wind erosion.From the perspective of soil wind erosion prevention and control,the porosity of Caragana korshinskii belt is 50%,and the surface soil can be well protected if the height of stump is kept at 30 cm. |
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