| Due to the negative impact of industrialization and urbanization,the problem of heavy metal pollution in urban soils in China is serious,among them,cadmium?Cd?is one of the heavy metals with relatively serious pollution.Cd is highly mobile and migrated and spreaded in the environment around the city,affecting plant growth and threatening human health.It is the responsibility of landscape architects to solve urban soil pollution problems,restore plant landscapes,and eliminate negative spaces within cities.The degree of soil pollution is analyzed by engineering techniques,and different schemes are formulated according to different pollution levels to repair,reduce or eliminate heavy metal pollutants in the soil and restore soil service functions.Under the guidance of landscape garden theory and methods,the use of resistant garden plants for plant landscape construction and the establishment of a stable ecosystem.This experiment took cadmium pollution as an example,and divided soil pollution into light,moderate and severe,and conducted research separately.The research results mainly include:The pot experiments were carried out with Sedum,Oxalis corniculate L.?Oxalis?,Calendula officinalis?Calendula?,Buxus sinica?Rehd.et Wils.?cheng subsp.sinica var.Parvifolia M.Cheng?Buxus?as test materials,and 11mmol kg-1 oxalic acid?OA?was added to the soil contaminated with mild Cd to explore the intercropping of enriched plants-landscape plants to repair the impact of urban mild Cd contaminated soil.The results showed that the addition of OA significantly increased the biomass of Oxalis and Buxus,while the Calendula showed toxic symptoms.The addition of OA decreased the accumulation of Cd in the three landcsape plants,and the accumulation of Cd in the sedum was significantly increased.Compared with the control group,the Cd content in the soil increased significantly after OA treatment.In summary,the treatment of 11mmol kg-1OA can promote the repair of mild Cd contaminated soil with the system of Sedum-Oxalis and Sedum-Buxus intercropping system.Used bentonite,dead pig biochar and corn stover biochar,the soil culture test was carried out at 5%application rate to investigate the effect of different passivating agents on the passivation effect of urban moderate Cd contaminated soil and the growth of Tagetes patula L..The results showed that the treatment of dead pig biochar increased the biomass of Tagetes patula L.,and significantly reduced the accumulation of Cd in the body.The corn straw biochar inhibited the growth of Tagetes patula L..The treatment of dead pig biochar effectively reduced the bioavailability of Cd in soil.And the effect of increasing the content of mineral elements such as K and P in the soil is most significant.In this experiment,the addition of 5%dead pig biochar has the best effect on optimizing soil physical and chemical properties,promoting the growth of Tagetes patula L.and reducing the effective Cd content in the soil.In the process of Cd contaminated soil remediation,the restoration model and test results of the pot experiment were applied to the soil restoration and landscape construction of Xiaodanshan Park?Shangyu City,Zhejiang Province,China?,and the formula for making soil-free bricks was found.Different levels of pollution use different methods of repair to reduce or even remove heavy metal pollution from the soil and to build plant landscapes.In the design of plant landscape,taking the restoration of the ecological environment as the core,taking into account the ornamental nature of the landscape,restoring the landscape service function of the park,and creating a livable living environment.The research content of this paper combines engineering technology and landscape design to provide innovative repair ideas for the repair of heavy metal contaminated soil in cities.It can effectively remove broken land and decay in the city,promote the construction of livable environment and the city's Continue to develop. |
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