| The vegetation diversity and the soil fertility quality restoration are the key factors for vegetation construction and eco-environmental sustainable development in Liupan mountain. To meet the requirement of eco-environmental construction, the fields with different successional ages in Liupanshan forest area were chosen to explore the changes in vegetation diversity and the soil fertility quality in different restoring ways. Simple correlation,canonical correlation analysis and path coefficient analysis were used to analyze the relationships of species diversity with vegetation coverage types, soil fertility factors. The evaluation system of soil quality evaluation and the vegetation coverage types which effectively improve vegetation diversity and soil quality preliminary was established. The goal of the present research was to demonstrate the mechanisms for vegetation rehabilitation and soil quality care in Liupan Mountain forest area,and enrich the theory and method for soil quality management. The results obtained were summarized as follows:â… . The result indicated that:Liupan mountain area lies in the south forest grassland belt of temperate zone grassland,the vegetation types are divided into meadow grassland and defoliate broad forest ,there are 7 vegetation-type groups,32 types and 88 formation groups,113faculty,382category788 species through statistic, analyse and classification for vegetation.There are Hua mountain pinecone forest,Pinus forest,Larix prinnipis forest,Quercus mongolica forest,Populus dowidiana forest and so on.â…¡.Improvement of environmental quality was reflected on the relationship between community succession and diversity which accelerated succession course of vegetation restoration. In the early stage of forest building, abundance index was only 0.505,diversity index 0.776 and evenness index 0.416. After 50 years,the indices of oasis environment for abundance,diversity and evenness are 0.861,1.241 and 0.761,respectively.There are difference along different succession community types,but the difference is not markedness in Liupan mountain area.All in all, evenness index in the late stage of succession is greater than ones in the early and middle courses of succession. Along the succession gradient, the change for species diversity is obvious.â…¢.In the course of succession, there were significant differences on soil chemical properties. The content of soil organic substance was highest in broadleaf and coniferous mixed forest, while lowest in coniferous forest. Broadleaf forest has the greatest organic carbon variability than other forest usage types,while the content of coniferous forest is lowest in the surface layer. The ranking of the organic carbon content of aberrance coefficient is as follows:Secondary grassland >Broadleaved and coniferous mixed forest >Coniferous forest>Coniferous mixed forest from1 to 10cm layer,and Broadleaf mixed coniferous forest>Broadleaf mixed forest>Secondary grassland>Coniferous forest>Coniferous mixed forest from20 to 40cm layer.Soil nitrogen was shown as Secondary grassland>Broadleaf mixed forest>Coniferous forest>Broadleaf mixed coniferous forest>Coniferous mixed forest. From the change of aberrance coefficient,it indicated that,broadleaf mixed forest and coniferous mixed forest had acute variety in the soil profile,but Secondary grassland was relatively slow. There were different degree along different soil availab types basically. Soil available phosphate content was highest in broadleaf mixed coniferous forest(0.55mg.kg -1), while lowest in coniferous forest (0.42mg.kg -1), though the difference is not significant.The present studies indicated that along the vegetation succession,the community structures changed accompanied by the disciplinary changes of total nitrogen,available phosphate and organic matter,and the important values of tree layers increase.â…£. Larix prinnipis should be considered in priority in order to restore vegetable beneficial as soon as possible in recovering and rebuilding vegetable in the future in hilly-gully region of Loess plateau. Natural community should be sealed and enabled coverage to raise gradually,at the same time,plants in herb layer should be not disturbed and promoted to develop ecology benefit. Man-made forest should be remade in order to emerge recession of community and forestation failure.By building soil quality evaluate systerm,we got following ranks: broadleaf mixed coniferous forest>broadleaf mixed forest>coniferous forest> coniferous mixed forest> secondary grassland,in other word,arbor holt has import effect on resume amend of soil,thereinto,broadleaf mixed coniferous forest is the first,broadleaf mixed forest second and secondary grassland last.The models on the vegetation reconstruction in the upland and ravine regions of northwestem proposed in this study could be used in guiding the ecological reconstruction in those similar regions.
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