城市高架桥底困难绿地改良——以深圳市丰盐路高架桥底绿地为例

Improvement of difficult green space under urban viaduct,taking the green space under Fengyan Road viaduct in Shenzhen City as an example

以深圳市丰盐路高架桥底困难绿地为研究对象,利用自主研发土壤改良剂改良原土,并栽植3种常用的耐阴植物鸭脚木(Heptapleurum arboricola)、红背桂(Excoecaria cochinchinensis)和八角金盘(Fatsia japonica),分析其适应性,筛选适生植物。结果表明,改良后的土壤pH值从8.3降至7.6,容重从1.42 g·cm-3降至1.27 g·cm-3。土壤有机质、速效养分和相关土壤酶活性有显著提升(P≤0.05)。适生植物筛选发现,鸭脚木栽植4个月后成活率维持在98%以上,盖度由57%提升到87%。八角金盘栽植4个月后成活率为80%,盖度无显著提升。红背桂栽植2个月后的成活率和盖度分别降至22%和14%,4个月后则分别只有18%和8%。分析根系性状发现,鸭脚木的扎根深度和根系生物量要显著高于红背桂和八角金盘(P≤0.05),红背桂根系生物量最低。鸭脚木在丰盐路高架桥底绿地表现最佳,可结合土壤改良技术进行进一步推广。

The study focused on the difficult green space under Fengyan Road viaduct in shenzhen city,using self-developed soil amendments to improve the soil quality,and planting three commonly used shade plants,namely Heptapleurum arboricola,Excoecaria cochinchinensis,and Fatsia japonica,to analyze their adaptability.The results showed that the soil pH decreased from 8.3 to 7.6,and the bulk density decreased from 1.42 g·cm-3 to 1.27 g·cm^(-3) after soil improvement.There was also a significant increase in soil organic matter,available nutrients,and related soil enzyme activities(P≤0.05).According to the adaptable plants selection test,the survival rate of H.arboricola remained above 98%after 4 months,and the coverage increased from 57%to 87%.The survival rate of 4-month F.japonica is 80%,with no significant improvement in coverage rate.2 months after planting,the survival and coverage rate of E.cochinchinensis decreased to 22%and 14%,respectively,while after 4 months,they were only 18%and 8%,respectively.Analysis of root traits revealed that the rooting depth and root biomass of H.arboricola were significantly higher than those of E.cochinchinensis and F.japonica(P≤0.05),with E.cochinchinensis having the lowest root biomass.In general,H.arboricola performed best in the green space under Fengyan Road viaduct,and can be furtherly promoted in combination with soil improvement techniques.