Study On The Effects Of Plant Sand Barriers On Improving Environmental Factors In Horqin Sandy Land

Based on placing five different kinds of shrub checkerboard in Balinyou district of Chifeng city east of Horqin sandy land, the effect of reducing wind and stabilizing sand has been studied and compared with floating sand. From May to September in 2005, a series of field investigation and experiments have been carried out in trial sites to study the improved effect of plant sand barriers on microclimate change, soil temperature, soil moisture, vegetation rehabilitation and litter mass, and the meliorative effect of all kinds of plant sand barriers has been analyzed and compared by utilizing principal component analysis (PCA) of SPSS.The results show that: 1) the checkerboard has a positive effect on microclimate factors, such as wind speed, air temperature, atmosphere humidity and soil temperature, but not obvious. 2) Soil moisture does not change obviously with soil depth, but which does dramatically with different kinds of checkerboards. Rainfall mainly concentrates on 40cm depth soil underneath the ground. Among different checkerboards, the difference of soil physical-chemical properties are notable, including the soil bulk density, porosity, the saturation moisture capacity of the soil and water holding capacity, pH value, organism, N, P and K. 3) The construction of checkerboard will increase the species composition, diversity index, be beneficial for vegetation rehabilitation and decrease the superiority at the same time. On the view of life form, annual-biennal vegetation and perennial vegetation take the predominance alternately. On the view of species composition, Chenopodium album is dominant firstly, then gramineous and feverfew, finally legumina. 4) Artificial shrub and herbaceous vegetation, become sparsely automatically because of the competition of water, and artificial shrub sand fixation system evolves into the natural herbaceous-dominant ecosystem. 5) Three kinds of checkerboard, including Hedysarum mongolicum, Hedysarum mongolicum+ Salix gordejevii and Caragana microphylla, have obvious spatial variability, others may have the spatial variability less measurement scale. 6) Compared with the microclimate factors, soil physical -chemical properties and the effect of vegetation rehabilitation by using principal component analysis (PCA), the checkerboards of Artemisia halodendron Caragana microphylla+Hedysarum mongolicum and Artemisia halodendron+ Caragana microphylla have more efficient influence on reducing wind and stabilizing sand than Salix gordejevii+ Hedysarum mongolicum and Hedysarum mongolicum.