Study On Characteristics Of Roadside Greenbelts In Datong City

Greenbelts along roadside are the skeleton of urban green space system.They play an important role in improving the ecological quality of the city and in creating the characteristic features of the city.The ecological and aesthetic benefits are not only affected by the types and allocation patterns of greening plants,but closely related to soil fertility in roadside greenbelts.Therefore,the evaluation of the landscape and soil fertility of greenbelts along roadside can help us to grasp the quality of urban road green space and the existing problems,and better predict the changing trend of green space landscape quality and ecological benefits,so as to provide scientific support for the formulation of scientific and rational conservation measures.Taking 18 main roads in Datong City of Shanxi Province as the object of investigation,the species composition,allocation pattern and soil physical and chemical properties of greenbelt plants were investigated.On this basis,the analytic hierarchy process(AHP)was used to construct the landscape evaluation system,and the landscape comprehensive evaluation of the investigated road green space was carried out.The soil fertility of each road was evaluated by Nemerow index.The results showed that:(1)There are four main cross-section forms of greenbelts of road in Datong City,including one-board-two-belt,two-board-three-belt,four-board-three-belt and four-board-four-belt,among which four-board-three-belt accounts for 72.1%.There are six types of green space structure,namely,tree+hedge,tree+small tree+hedge,small tree+hedge,tree+small tree+shrub+hedge,small tree+shrub+hedge,shrub+hedge and shrub+hedge.There are 35 species of greening trees,belonging to 15 families and 24 genera.Among them,20 species belong to 12 genera and 9 species belong to 9 families,and 8 genera and 9 species belong to 5 families and shrubs.Trees are mainly Sophora japonica,Pinus tabulaeformis,Begonia sibirica and Euonymus hupehensis,while shrubs are mainly cloves and plum,while hedgerows are mainly planted with Euonymus microphylla,Berberis purple and Ligustrum aureus.(2)An evaluation system consisting of 11 indicators including overall coordination,vertical structure,horizontal structure,morphology,ornamentality,landscape spatiality,species composition,greening coverage,health status,canopy density and life-form structure of plant landscape was constructed.The weight of each landscape ecological factor was determined by analytic hierarchy process,and the plant health status,plant species composition and life-form structure in the index layer were determined.The vegetation coverage and canopy density have higher weight coefficients.The evaluation results of each road landscape show that there are 4 Grade ?sections,10 Grade ? sections,3 Grade ? sections and 1 Grade ? section.The overall landscape quality of Datong urban road is good.(3)The analysis of soil fertility showed that the average soil bulk density of 0-15 cm of road green land in Datong City was 1.39 g/cm 3,the average PH value was 8.39,and the contents of organic matter,total nitrogen and total phosphorus were low.According to Nemerow index method,there are 6,7 and 5 roads with good,medium and poor evaluation grades respectively,but there are no roads with good evaluation grades.The overall soil fertility of roads in Datong City is poor.