| As an urban green infrastructure,Rain Garden is one of the effective ways to optimize and solve urban waterlogging.Its ecological function has been widely proved.Among them,soil health is one of the important factors that determine the quality of rain garden construction.In this paper,six rainwater gardens with similar environmental characteristics in North China were selected as research samples.Soil samples were collected in three functional areas,including rainwater garden runoff area,buffer zone and water storage area,in spring and summer.The soil physical properties such as soil texture and soil moisture content,soil physiology such as soil acidity and alkalinity and soil organic matter were determined by experiments,and the characteristics and their changing laws were analyzed.According to the physical and chemical characteristics of soil,they were from plants,soil and vertical.Three aspects of structural composition propose the construction and management strategy of rainwater garden,which provides relevant reference and basis for rainwater garden design.This study analyzed the soil physical characteristics of rainwater garden.The physical properties of soil generally show that spring is better than summer.In the soil texture,the sand texture is relatively stable compared to the loam and clay.The soil particle size changes only 1% to 5% of the sand,5% to 22% of the loam,and 9% to 14% of the clay.Clay will show an increasing proportion of sand particles under the scouring of rainwater;in terms of soil moisture content,the trend of different functional zones is generally the runoff zone <buffer zone<water storage zone,the optimal soil moisture content of each functional zone of rainwater garden The change of soil water content is small,only 0.5%~3.5%,while the lower soil moisture content is relatively large,ranging from 0.9% to 10.6%.Soil chemical characteristics in rainwater garden.Soil chemistry generally shows that spring is greater than summer.In soil pH,the pH value of rain garden soil showed a phenomenon of spring more than 0.5 in summer,but the pH value of soil in each functional area changed very little.In terms of soil organic matter,it showed spring more than 10~20g/kg in summer,spring water storage.The area is higher than the runoff area and the buffer zone,and the variation range is about 1~16g/kg.In summer,the water storage area is smaller than the runoff area and the buffer zone,and the variation range is 2~10g/kg.The strategy of construction and management of rainwater garden is put forward in this study.In the aspect of rainwater garden plants,the construction and management strategies of rainwater garden are given from plant species selection,plant allocation and late plant management.For example,nitrogen-fixing plants should be selected in runoff area,hydrophilic plants should be selected in clay buffer area,and plants with strong barren resistance and waterlogging resistance should be selected in water storage area.In two aspects of management,the construction and management strategies of soil are put forward,such as mixing sand with clay and poor drainage soil,soil fertilization is an effective way to supplement soil organic matter;in vertical structure of rainwater garden,construction and management strategies are given respectively from three aspects: site gradient,vertical structure composition and late maintenance,including seepage control materials in site regularly.Change or clean up,maintain the ecological stability of the site environment and so on. |
