| The green soil-vegetation system achieves the effects of rainwater emission reduction and pollution reduction through absorption,retention,utilization,infiltration and purification.Therefore,sponge-type green space is an important part of sponge city construction.Shenzhen has established a small number of sponge-type greenfield test demonstrations in Guangming New District and other places,but lacks understanding of the soil seepage characteristics of sponge-type green space,and there is no relevant soil improvement supporting technology as a support.In this study,the sponge-type greenbelt soils in five different functional areas of the first national sponge city construction demonstration zone in Guangming District,Xinming Park and surrounding roads were taken as the research object,and the soil water storage characteristics were analyzed with ordinary green soil as the control.Analysis the difference of water storage characteristics,and exploring the sponge green land soil improvement technology,provide technical support for the promotion of Shenzhen sponge green space construction and sustainable urban development.Research indicates:(1)The soil physical condition of Guangming New City Park is good overall.The soil bulk density of the surface layer(0-10 cm)was 1.06-1.45 g/cm~3,the total soil porosity was45.23-80.99%,the non-capillary porosity was more than 40%,and the capillary porosity of the road planting retention tank was the largest The maximum water holding capacity of0-10 cm soil in Guangming New City Park was 29.06-69.51%,the water holding capacity of capillary was 24.44-63.17%,the water holding capacity in the field was 22.64-62.35%,the soil water holding capacity was generally good;the water holding capacity of the capillary and the field water holding capacity were road vegetative.The retention tank was higher than the other functional areas.The initial permeability and stable permeability of sponge-type green land are generally higher than that of ordinary green land,but there was a large variation in soil permeability coefficient.(2)The 12 improved soil porosity index,water holding index and permeability index were significantly improved compared with unmodified soil(CK),and the minimum weight was 0.98 g/cm~3(CK was 1.09 g/cm~3).The porosity was 52.87-64.06%(CK was40.86%),the maximum water holding capacity,capillary water holding capacity and field water holding capacity were 37.05-56.92%,30.00-53.23%,28.91-51.46%,respectively,and the maximum values were 15.64%,20.22%,27.34%higher than that of unmodified soil.The difference in permeability of different improved soils were obvious.The order of different treatments was T10>T11>T06>T12>T04>T07>T02>T01>T03>T09>T08>T05>CK.When the soil volume ratio was 80%,the addition of fly ash can improve the soil water holding capacity of the improved soil;when the soil volume ratio was 70%,80%,the addition of garden compost can significantly improve the soil permeability.The typical correlation analysis showed that the improved soil capillary porosity index was closely related to permeability and water holding capacity.The cultivation experiment showed that except for T08 treatment,the plants grown on the other 11 improved soils grew well,and the accumulated biomass above the ground was higher than that of the control or the control,but the root growth was poor.Adding fly ash and garden compost was more conducive to plant growth under 80%soil ratio treatmentIn summary,the soil seepage storage characteristics of sponge-type green land in Shenzhen were better and generally higher than ordinary green land,but different sample points has large differences.T12 treatment(80%soil+10%fly ash+10%garden compost+gypsum)was the best way to improve the local soil. |
PDF Full Text Request