关键词: 永定河沙地, 土地利用, 风蚀

Abstract:

The threshold velocity for transportation of sand, roughness, windblown sediment, wind-sand flow structure, soil mechanic composition and wind erosion amount were studied in 4 different land-use types (field land, forest land, wild grass land, flood land) in the Yongding River sand land in Beijing. Conclusions can be drawn as follows. Firstly, the order of wind speed of displace and roughness were forest land, wild grassland, field land, sparse wild grass land, flood land. Secondly, At the wind speed, there are significant differences in sand flux among different ground cover. In the height of 0～20 cm, the height increased while the sediment discharge percent of sand flux reduced. There were significant differences in the sand flow formation in different land use types. Thirdly, mechanic composition of sand particle mainly composed of silver sand in flood land and sparse wild grass land,while others were made of silver sand, particle silver sand and floury sand. Fourthly,the amount of wind erosion and sand sediment was different in land-use types at the same time. Fifthly, some advice was put forward in:improving the vegetation coverage in wind sand prevention and control; changing farming technology.

Key words: Yongding River sand land, land-use types, wind-erosion