Effects of Different Types and Depths of Substrates on Sedums’ Growth and Temperature Reduction for Extensive Green Roof in Taiwan

• Main Authors: TSAI, SZ-CHENG, 蔡斯丞
• Other Authors: CHANG, LI-SHIN
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/37edr5

碩士 === 逢甲大學 === 景觀與遊憩碩士學位學程 === 107 === Nowadays, the temperature in the urban areas of Taiwan has increased year by year. According to the research, the green roof can increase the urban green coverage and reduce the heat island effect. The extensive green roofs are suitable to use on general building due to the low roof load, low maintenance and management, and low-maintenance demand. Sedum plants were drought tolerance and vitality, but in Taiwan the plants’ roots are easily to die due to high temperature and heavy rain in summer. Therefore, the objectives of this study were to find what kinds of the substrates were suitable for growth of Sedum plants and what substrates depth and irrigation frequency should be used for a sedum green roof in Taiwan. The results could be applied to the promotion and construction of Sedum on extensive green roof in Taiwan. In this study, we selected three kinds of the drought-tolerant Sedum, Sedum linear Thunbg, Sedum mexicanum and Sedum sarmentosum, three types of substrates, red brick substrate and soil-less substrate, and soil-amended substrate, two depths of substrates, 7.5 cm and 15 cm, and the irrigation and none–irrigation maintenance as dependant variables for the research. In addition to the green coverage changes of the planting, the temperature of the slab, surface layer of a pot and bottom of a pot of each treatment were recorded. The results show that among three substrates, the green coverage rate of Sedum plants in soil-amended substrate was the best for succulent plant growth. In summer, the temperature of the bottom of a pot for soil-amended substrate treatment was the lowest, In other words the cooling effect was good. Comparing the two substrate depths, the green coverage rate of Sedum plants with 15 cm depth soil grew better than those with 7.5 cm deep substrate. For green coverage of none-irrigation Sedum was not worse than that with irrigation, in some seasons even better. The temperature of the bottom of a pot with irrigation was lower than that with none-irrigation so the cooling effect is good. Sedum linear Thunbg and Sedum mexicanum will recommend to be used for rooftop greenery since they are easy to survive. However, the growth of Sedum sarmentosum was the worst and the mortality rate was high during the experiment. It is recommended to use 15 cm-deep soil-amended substrate for cultivation of sedum in the future while constructing extensive sedum green roofs so good cooling effects could be expected. Sedum can also be cultivated none–irrigation so it could reduce the regular maintenance fee and efforts.