Study On Water And Soil Conservation Function And Landscape Evaluation Of 8 Species Of Magnoliaceae Ornamental Plants

With the promoting the construction of ecological cities,landscape plants satisfy people’s aesthetic needs in the urban environment,and also play important ecological benefits.Plant landscape evaluation is the scientific basis and basis for the development and utilization of garden plants.The landscape evaluation research on garden plants promotes and improves the application of landscape plants in urban green space construction.Magnoliaceae plants have high ornamental value and are widely used in landscaping construction,but there is a lack of exploring the landscape value of Magnoliaceae plants from the perspective of water and soil conservation ecological functions coupled with landscape viewing effects.Therefore,this paper selects 8 magnolia species such as Michelia shiluensis,Michelia macclurei,Michelia crassipes,Michelia foveolata,Michelia maudiae,Michelia odora,Manglietiastrum sinicum,Manglietia lucida as the research objects to investigate their litter layer hydrological effects,soil layer water conservation,carry out research on soil conservation function and landscape characteristics,use the entropy weight Topsis method to evaluate the soil and water conservation function of magnolia plants,and conduct landscape evaluation of magnolia plants by AHP analytic hierarchy process,which is helpful for the selection,development and utilization of magnoliaceae plants and the development and utilization of magnolia plants.Landscape optimization configuration in gardens provides basic theoretical basis and scientific guidance.The results of the study are as follows:（1）The variation range of litter accumulation of 8 Magnoliaceae plants was1.18-4.00 t·hm^-2,M.shiluensis had the largest accumulation,M.sinicum the smallest,and M.lucida had a high degree of litter decomposition.The maximum water holding capacity of the litter layer varied from 12.52 to 22.26 t·hm^-2,the effective holding capacity varied from 6.28 to 25.54 t·hm^-2;M.shiluensis has better water holding capacity.The water holding capacity and water absorption rate of the litter and the soaking time have a logarithmic function relationship K=alnt+b,R²>0.96 and a power function relationship V=ktⁿ,R²>0.94,respectively.The water loss and water loss rate of litter and water loss time are logarithmic function relationship Q=alnt+b,R²>0.97 and power function relationship S=ktⁿ,R²>0.93,the water loss process is compared The water holding process proceeds more slowly.（2）The soil bulk density of the eight Magnoliaceae species varied from 1.29 to 1.61g·cm^-3,and the total soil porosity varied from 29.33 to 47.58%.Soil saturated water holding capacity,effective water holding capacity and field water holding capacity were 293.28～475.83 respectively t·hm^-2,28.27～65.06 t·hm^-2and 15.66 to 32.00%.M.shiluensis had the best soil water-holding capacity,followed by M.crassipes and M.foveolata,and M.sinicum was the worst.The soil infiltration rate varied from 0.91to 5.04 mm·min^-1.The soil infiltration time and infiltration rate showed a power function relationship f=at ^b,R ²>0.94.（3）The soil organic matter of different magnolia plants decreased with the increase of soil layer thickness,and the soil organic matter varied from 13.19 to 20.88g·kg^-1,and M.crassipes was the largest.The soil total nitrogen content of the 8 plants fluctuated from 0.96 to 1.22 g·kg^-1,the ammonium nitrogen content was 7.00 to 9.82mg·kg^-1,and the nitrate nitrogen content was 9.51 to 14.20 mg·kg^-1.M.crassipes had good nitrogen fixation.The soil total phosphorus of different plants fluctuated between 0.16-0.22 g·kg^-1,and the soil total potassium fluctuated in the range of11.01-18.81 g·kg^-1.The soil conservation ability of M.crassipes was the best,and the soil conservation ability of M.maudiae was poor.（4）Most of the 8 species of Magnoliaceae in the experiment were broadly oval in tree shape,and most of the plant leaves were obovate and leathery.The bell-shaped flowers of different plants account for most of them,and the flowering period is spring and the flowers are fragrant.The flowering period of M.shiluensis and M.foveolata lasts for three months.The fruiting period of various plants is mostly in autumn,and most of them are green fruits.（5）The soil and water conservation functions of 8 Magnoliaceae plants were evaluated by TOPSIS method.The order of soil and water conservation capacity was as follows:M.shiluensis>M.crassipes>M.foveolata>M.macclurei>M.lucida>M.odora>M.sinicum>M.maudiae.The AHP analytic hierarchy process was used to evaluate the landscape of different species of Magnoliaceae.The comprehensive evaluation value of landscape benefits from large to small was as follows:M.shiluensis>M.crassipes=M.foveolata>M.odora>M.lucida>M.macclurei>M.sinicum>M.maudiae.The difference method was used to classify the landscape into five value grades:I,II,III,IV,and V.The comprehensive evaluation value of grade I is>2.23,grade II is 2.05-2.23,grade III is 1.86-2.05,and grade IV is 1.68-1.86,V level≤1.68.M.shiluensis has the highest comprehensive evaluation value,which is grade I.M.crassipes and M.foveolata are both grades II,and the comprehensive evaluation value is relatively high.The comprehensive evaluation value of grade IV is high,including M.sinicum,M.lucida,M.macclurei;M.maudiae is grade V,and the comprehensive evaluation value is average.In summary,M.shiluensis,M.crassipes and M.foveolata have better ecological functions of soil and water conservation and landscape effect.In the landscaping process of Magnoliaceae landscape plants,M.shiluensis,M.crassipes,M.foveolata and other tree species can be prioritized and allocated reasonably.Plant species to achieve the optimization of landscape aesthetics and ecological effects.