The Study On The Diversity Of Greening Plants Of Urban Roads And Its Correlation With Soil Factors In Linfen City

The rapid increase of urbanization has led to a series of major practical problems such as population intensive,traffic congestion,environmental pollution and ecological degradation.In order to solve a series of problems brought about by the urbanization process,urban ecological environment will be used to improve the urban living space.And it is especially important to improve the quality of life of the people.Urban road green space and urban soil are important components of urban ecosystem.Studying plant diversity and soil physical and chemical properties of urban roads is of great significance for improving urban environment and promoting sustainable development of urban ecosystems.In this paper,32 roads in Linfen City were used as research objects of plant diversity,and their plant species composition,species richness,frequency,plant community ecological structure and plant diversity were analyzed.19 roads were used as research objects of soil physical and chemical properties.From the aspects of bulk density,total porosity,saturated water content,capillary water holding capacity,saturated hydraulic conductivity,p H value,electrical conductivity,organic matter content and total nitrogen total phosphorus content,etc.The variance analysis of soil physical and chemical properties was carried out by SPSS software.The correlation between soil physical and chemical properties and plant diversity index and soil physical and chemical properties were studied,and the correlation between soil and plant diversity index at different depths was compared.The research results are as follows:(1)There are 36 species of road greening plants within the survey area of Linfen City,belonging to 19 families and 29 genera,of which woody plants account for 32.8% of the total number of 88.9%.There are 8 species of evergreen trees in woody plants,24 species of deciduous trees,16 species of arbor and 16 species of shrubs.In the arbor layer,there are high frequency and richness,such as scorpion,two-ball sycamore,one ball sycamore,poplar,juniper,white poplar,cedar,etc.;in the shrub layer,big leaf boxwood(ball),Clove,mountain peach,crape myrtle,hibiscus,pomegranate,etc.have higher frequency and richness;herbaceous flowers have lower abundance.The ratio of the species of evergreen and deciduous trees in the road greening plants in the survey area of Linyi City is 1:3,and the species ratio of trees to shrub species is 1:1,which is specific to the road green belt,arbor species and shrubs.The species ratio of tree species is between(1:0.5)and(1:8).(2)The road section of Linfen City's roads with two plates and three plates and four belts has the highest application frequency,which is 43.75%;and 34.38% of the road vertical structures are trees + shrubs + hedges,and 28.13% of the roads only have arbor layers.(3)Among the roads surveyed in Linfen City,68.42% of the first-level road greening uses 5 or more plants;50% of the secondary roads use only one type of plant;the third-level roads are composed of a single species.Shannon-Wiener diversity index(H),Simpson diversity index(D),and Pielou evenness index(E)all show the characteristics of the arbor layer < shrub layer.The level of plant diversity increases as the grade of the road increases.(4)The soil bulk density of roads in Linfen City was 2.2.21 g·cm-3,accounting for 42.11%,the soil bulk density was larger,and the soil was tighter;the total soil porosity was <50%,accounting for 42.11%,and the soil saturated water content was <52g.78.95%,soil capillary water holding capacity <45g accounted for 68.42%,soil saturated water content >1 mm/min only accounted for 10.53%,soil total porosity is small,soil water retention,ventilation and water permeability is poor.Correlation analysis of soil physical properties shows that soil bulk density is significantly negatively correlated with soil total porosity,soil saturated water content,soil capillary water holding capacity and soil saturated hydraulic conductivity(P <0.01);total soil porosity The degree was significantly positively correlated with soil saturated water content,soil capillary water holding capacity and soil saturated water content(P <0.01).(5)The average PH value of road soil in Linfen City is 8.53 overall strong alkaline,the average conductivity is 284.03?S/cm,and the average organic matter content is 8.502 g·kg-1 at medium to low level.The average nitrogen content was 0.243 g·kg-1 at an extremely low level,and the average phosphorus content was 0.786 g·kg-1 at the middle and lower levels.Through the significant difference analysis of the chemical properties of soils with different depths,the deep soil is significantly more alkaline than the topsoil;soil conductivity and soil total phosphorus content are not significantly different under different depths of soil;surface soil organic matter content And total nitrogen content is significantly higher than deep soil.(6)Correlation analysis of soil chemical properties showed that soil p H value was significantly negatively correlated with soil conductivity,soil organic matter content,soil total nitrogen content and soil total phosphorus content(P <0.01);soil conductivity and There was a significant positive correlation between soil total nitrogen content and soil total phosphorus content(P <0.01),and positive correlation with soil organic matter content(P <0.05).Soil organic matter content,soil total nitrogen content and soil total phosphorus content showed significant Positive correlation(P <0.01).(7)Through correlation analysis between road plant diversity index and soil chemical properties at different depths,it is found that there is more significant correlation between chemical properties of deep soil and road plant diversity.