Study On Effects And Mechanism Of The Integrated Controlling Sand Hazard To Highway In Otindag Sandy Land

The experimental plots was on the two sides of provincial highway throw Otindag Sandy Land in Inner mongolia.mainly.The primary sand-barrier materials are Salix gordejevii Y.L.Chang et Skv. and Salix microstachya Turcz.It was studied that the stability and resisting wind effect of the preservation system composed of sand-fixation belt with semi-buried checkboard sand barrier and shifting-sand-stop belt with high-banded wicker sand barrier , and the differences of plants gowth in enclosed belt along the two sides of the road by wind observation and investigation in the field.The movement of wind and sand in the plant communities in the earlier spring was tested,The objetive was to form an earlier stage protecting belt for the plants emergence and growth and to testablish the sand-resistant stable plant communities. It was the vital fuctional belt which accomplish permanent ecological protection in the preservation system.1.After determine the wind spead of two group of high-banded wicker sand barrier with different density,15,18,21,24 and 27sticks per meter and 15,25,35 and 45sticks per meter in drifting sandy land and semifixed sandy land,and studying the wind spead variety, resisting wind effects and roughness degree of the high-banded wicker sand barrie, coming to a conclusion that the density of 24～25 sticks/meter and 4 meters between two sand barriers are appropriated for high-banded wicker sand barrier.2.Sand-fixation belt with 1.2m×1.2m semi-buried checkboard sand barrier,ground roughness degree reached to 10.8902cm,and resisting wind effect reached to 43.29%, It have changed the structure of sand flows, lowered the sand-transportation rate.3.Sand barriers composed of sand-fixation belt and shifting-snd-stop belt, Its resisting wind effect reached to 54.4%,76.5%,64%,62.3%,and ground roughness degree reached to7.56cm,12.1cm,12.5cm,5.94cm in gentle-sand land, excavation section, powerful blowing territory, wind erosion pit at the two sides of highway respectively.the shifting-snd-stop belt stop the sand within 23 metres width in the front of 50 metres wide shifting-snd-stop belt.4.Salix gordejevii, Caragana microphylla, Hedysalum laeve, Agropyron desertorum, Melilotus, Artemisia, Astragalus adsurgens,their survival rate and preserving rate are 90.4% and 93.9% respectively.The third year after planted, Salix gordejevii, Hedysalum laeve growth height are 147cm and 182cm,they are highest tlayer in the community. Artemisia, Astragalus adsurgens,Caragana microphylla growth height are 43～58cm, they are the middle layler in the community.Agropyron desertorum growing 32cm height ,it is the lowest layer in the community.5.In the enclosing belt,the new plants reach to above 10 spieces,plants density reach to 26 individul plants/m~2,the coverage increased 12.3%.6.Wind spead varieties in the fixing-sand plant communities are nonlinear entirely,especialy at 60cm and 20cm height in the communities , wind velocity decrease exponentially(R~2≧0.91)or decreasse according to power function[R~2≧(0.70,0.97)] or polynomially(R~2=0.98).In the bigest wind season at winter and spring, resisting wind effect of the communities decrease from 60% to 25% with the gradient increasing from 12°to 26°,roughness degree decrease from 14.4cm to 1.4cm correspondingly.