Study On Vegetation Restoration And Evaluation Of Their Ecological Function On Two Main Types Of Bare Slope In The North

Restoration of uncovering slopes is a long-term and complex ecological project to reduce soil erosion,and to desertificate and improve the deteriorating ecological environment.This paper basing on the principles of restoration ecology and theory of sustainable development,classified the uncovering slopes of semiarid areas systemically from the basic research on restoration of uncovering slopes,and researched on the photosynthetic characteristics of shrub community,and the patterns and biomass of root system on the artificial uncovering slopes with artificial restoration.This paper talked about the uncovering slopes along the Mentougou District in Beijing 109 National Highway and Baihua Mountain scenic highway,and by choosing five vegetation restoration models at the town of Zhaitang and along with Baihua Mountain scenic highway.The author systematically studied the different ecological function of above models,and selected the optimal allocation model.By investigating Fushun Open-pit Coal Mine Western waste dump,the author also researched the evolution characteristics of vegetation and soil in shady and sunny slope where the waste rocks are discharged in different years.The results provide a theoretical basis for vegetation restoration of uncovering slopes in the north semi-arid areas.The main results are:1)Based on the causes and typical characteristics of uncovering slopes,and also other factors,the paper used muti-factor classification.This classification will be systematical.2)Researched on four excellent shrubs in water and soil conservation Vitex negundo var.heterophylla,Ziziphus jujuba var.spinosa(Bunge) Hu,Leapedezabicolor.Turcz,Amorpha fruticosa L.,and investigated roots distribution,the correlation of biomass on the ground and below-ground and the effective root density,The results are as follows:The below-ground biomass of Amorpha in different artificial community is relatively stable,have good mixed sowing performance;there is a strong correlation between on the ground and below-ground biomass of four shrubs,the effective root density of communityⅠis far greater than communityⅡ,Ⅲ. These results illustrated CommunityⅠis relatively reasonable.3)The results of study on net photosynthetic rate of four shrubs on the artificial uncovering slope showed:the changes on net photosynthetic rate and transpiration rate of Leapedezabicolor.Turcz.are both peak curve,water use efficiency on the uphill is lower than downhill and ground;the changes on net photosynthetic rate and transpiration rate of Vitex negundo var.heterophylla are both single peak curve,The difference of water use efficiency is not significant,the changes on net photosynthetic rate and transpiration rate of Ziziphus jujuba var.spinosa(Bunge)Hu are both single peak curve,water use efficiency on the uphill showed double-peak curve,the changes on net photosynthetic rate of Amorpha fruticosa L.is single peak curve,the transpiration rate showed double-peak curve on the uphill and ground,but,on the downhill showed single peak curve,water use efficiency on the ground is higher uphill and downhill significantly.4) On the Baihua Mountain,plant species configuration mode D(Amorpha fruticosa L.is+ Leapedezabicolor.Turcz.+ Vitex negundo var.heterophylla+ Indigofera pseudotinctoria Mats.+ Medicago sativa Linn.+ Dendranthema indicum(Linn.)Des Moul.) is largest on the aspects of index of species diversity,biomass,intercepted amount,the existing volume of litter,water capacity, soil porosity,structure coefficient and aggregate content,and is lowest on the aspects of soil aggregation, degree of aggregation and dispersion coefficient.Results of the evaluation of the ecological functions of the D model with the highest scores,is recommended in the region to promote a local plant-based combined with the plant shrubs and grasses.5) At the town of Zhaitang,model H(Betula platyphylla Suk.+ Juglans mandshurica+ Pinus tabulaeformis Carr.)is largest on the aspects of index of species diversity,biomass,intercepted amount, the existing volume of litter,water capacity,the index of soil anti-scourability and change on soil chemical properties.Evaluation of the H model with the highest scores,is worth promoting.6) On the shady slope in Fushun Western Waste Dump,with the scheduled length of the waste rocks,the number of species from the initial four families and five species increased to 14 families and 29 species.Vegetation from the very beginning of Cynanchum chinense R.Br., AmbrosiaartemisiifoliaL,Puncturevine Caltrop Fruit community turned to the Ulmus pumila L. community.Artificial slope in the proposed restoration of vegetation,drought-resistant elm trees as Ulmus pumila L.,Robinia pseudoacacia L.,Rhus typhina can be configured.On the area of stopped discharge waste rock,Betula platyphylla Suk.,Leapedezabicolor.Turcz.,Amorpha fruticosa L.,prunus armniacaL.,Ziziphus jujuba var.spinosa(Bunge)Hu and Hippophae rhamnoides Linn.can be configured.The results of Analysis of the physical and chemical properties of soil showed on the shady slope the mechanical components and soil bulk density of waste rock will be close to the level of farmland after 18 years.,and on the sunny slope,the above two aspects significantly lower than shady slope,meanwhile compared with farmland,the difference is significant.Soil on the shady and sunny slope,on the aspects of Soil organic content,the effective content of N,P and effective content was lower than the level of farmland.Available K content in the sunny and shady slope was significantly higher than farmland.The comprehensive evaluation of the ecological functions increased with the waste of life increases.The results of comprehensive evaluation on restoration of vegetation on the shady and sunny slopes,shows shady D＞sunny D＞shady C＞sunny C＞shady B＞sunny B＞shady A＞sunny A.