The Wind Tunnel Simulation Research On The Protective Measures Of Farmland In Desert-Region

Currently, the desertification crisis have been existed throughout the world .It reduces the space of the human survival and development,causes serious degradation of the land productivity and strengthenes the whole the deterioration of the ecological environment.The causes of land desertification and sand-dust disaster is soil wind-erosion ,the area of soil wind-erosion is more than half of tolal area in our country , which mainly distribute in northwest ,north and northeast of country .The soil wind-erosion of northern dry-farming land is most seriously. The occurance and development of farmlands soil wind-erosion is affected by climate , soil properties and tillage methods. The climate of north is drought ,farm land is make up of sand particles.The surface soil of farm land is easily eroded by wind , because ploughing and cultivating break the structure of soil, and ecological environment of the north is bad ,wind speed is fiercely in winter and spring , which caused occurance of soli wind-erosion in this area. So it is very important that how to change traditional tillage model and set up protection measurement which can keep soil moisture implement and control sand .In conclusion , Strengthening control soil wind-erosion in the north is quite significant to improve environment ,promote regional economy of sustainable development and reduce sandstorms.Based on Wind tunnel and PIV system to analyze different protection measure(shelter-belt , stubble mulch , winter wheat , film mulching) and combined-measures , it can draw reasonable protection measure , reduce the degree of sand calamity and resolve problems about coordinative development of Eco-environment Construction and regional economy .The research conclusion are shown as follows:1.All the single protection measures(shelter-belt,stubble mulch,winter wheat, film mulching) can reduce the quantity of wind erosion and protect farm lands. Shelter-beltB(3strips shrubs in the middle of 2 lines trees ,the height of tree:8m,tree desity: 3×4m, the height of shrubs:1.5m,shrub desity:0.5×2m) is the most valueable shelter-belts pattern. Tubble mulch4 is the best pattern , vertical film mulching(the direction of film mulching is vertical with wind direction) 2.The protective benefits of combined-measures are better than single protection measures. Shelter-beltB combined tubble mulch4 , shelter-beltB combined winter wheat and shelter-beltB combined vertical film mulching are optimal protection measures in all combined-measures. So we should popularized those measures to protect farm land in the sand drift areas in north Shaanxi province.