Analysis And Evaluation On Ecological Efficiency Of Vegetation Restoration In Yanghe Sandy Land, Hebei Province

Desertification is one of biggest environment questions in the world, which also is the the main manifestation of desertification in the north of our country. In recent years, the sandstorm occured frequently, which has do a great harm to ecological enviorment. Yanghe sandy land is one of the important dustsources of Beijing and Tianjing sandstorm source, located at Zhangjia kou area, Hebei province. To combat the wind sand disaster, in recent year this area has made ecological construct cosmically and gained favorable effects. this paper take Huangyangtan sandy land as example, based on a mass of research and observation, mainly research and evaluate the ecological efficiency which include soil wind erosion soil quality and soil water spatial distribution rule of vegetation restoration measures. The main research conclusion is showing as following:(1) The result of research on soil wind erosion shows that arbor forest belt has a better wind breaking and sand blocking benefit. The P.allbavar. pyramidalis forest belt built in 2001 has a best wind breaking effect, in the leewardside of the belt and forest has a better function of reducing wind speed than the windward side. The roughness most greatly achieves 36.4cm by Platycladus orientalis forest belt, for shift sandy land 458.85 times. The sand accumulation in shift sandy land is most; the following in turn is P.allbavar. pyramidalis forest belt, grassland fencing three years and Salix gordejevi.(2) The result of research on soil soil quality shows that the vegetation measure the soil particle composition by the coarse sand (1-0.25mm) and the fine sand (0.25 -0.05mm) primarily. The aeolian sandy soil clay (< 0.001mm) and the physical property clay (< 0.01mm) thecontent has the increase compared to the shift sandy land, the grassland under the fencing pattern is the highest, next is the bush forest land, the arbor forest land is lower. The content of organic matter and Total nitrogen by arbor forest land is higher, compared to the pure forest, the soil nutrients content in mixed forest(3) The result of research on soil water spatial distribution role shows that the grassland have good water sources holding effect,the high soil water content apeared in 0-5 0cm layer which distributed lots of plants;the soil water content of P.allbavar. pyramidalis and Elaeagnus angustifolia forest is higher in the layer 0-40cm which distributed plant roots, along with the layer become deeper and deeper, the soil water appear exhausted trend. Soil water content of shrub stand is situated between the two, in the deep layer the change of soil water content is gently.The seasonal change of soil water in sandy land has close relation with the preicipation. The max.all appear in July, the mix. Of shift land appeared in June. the plots with vegetation restorated measure appeared in August.(4) The result of research on ecological efficiency of eco-mat shows that eco-mat measure can control the sand quickly, reduce the soil temperature change range, increase the soil available K content and soil weight content, prolong the using time of vegetation to precipation.