Study on Wind Breaking and Sand Blocking Effects of Farmland Shelterbelts in Ulan Buh Desert Oasis

Wind velocity in different farmland shelterbelts in Ulan Buh Desert was observed.The results showed that wind breaking effect varies with forestbelt structure,height and porosity.Wind breaking effect of sparse structure shelterbelt is the best and porous structure takes second place,while the ventilation structure is the worst.On the basis of the same structure,the effect of reducing wind velocity becomes more obvious with the increasing of the height of shelterbelt.Moreover,shelterbelt can reduce the sand-transporting quantity,and the fall rate after the forest is more than the one before the forest.