2016 年 7 巻 1 号 p. 97-103
Though a green roof has been implemented mainly in city area due to the mitigation of heat island effect, it can also offer the benefit of energy saving to a building in rural area. A reuse of wastewater for irrigation may be an efficient practice for water conservation, especially in the water-scarce areas. In this study, we assessed the influence of frequent and intermittent saline irrigation on evapotranspiration (ET), dry matter yields (DM) and water-use efficiency (WUE) in crassulacean acid metabolism (CAM) plants used in the green roof program. The CAM plants Sedum kamtschaticum Fischer and Sedum oryzifolium were evaluated with turf grass, Cynodon dactylon. A sharp reduction in ET with an increase in soil salinity was found in CAM plants as compared to turf grass; however, the dry matter yield of CAM plants was higher than that of turf grass at the same amount of cumulative ET. Principle component analysis (PCA) was performed to group the treatments into fewer groups characterized by similar features. CAM plants were categorized by high DM and WUE. These features were expected to make green roof management sustainable because they have low water requirements with keeping the high-density vegetation.
