1. Plant growth-promoting microbes improve stormwater retention of a newly-built vertical greenery system
- Author
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Long Xie, Xi Shu, D. Johan Kotze, Kirsi Kuoppamäki, Sari Timonen, Susanna Lehvävirta, Department of Microbiology, Department of Agricultural Sciences, Helsinki Institute of Urban and Regional Studies (Urbaria), Helsinki Institute of Sustainability Science (HELSUS), Fifth Dimension - Vegetated roofs and walls in urban areas, Ecosystems and Environment Research Programme, Teachers' Academy, Biosciences, Sari Timonen / Research Group, Environmental Sciences, and Faculty Common Matters (Faculty of Biology and Environmental Sciences)
- Subjects
ROOFS ,Environmental Engineering ,Rain ,LOW IMPACT DEVELOPMENT ,INFRASTRUCTURE ,Vegetated roofs ,Management, Monitoring, Policy and Law ,RHIZOBACTERIA PGPR ,Urban stormwater management ,MANAGEMENT ,Water Movements ,Waste Management and Disposal ,11832 Microbiology and virology ,Microbial inoculation ,WATER RUNOFF ,Vegetated facades ,TRANSPIRATION ,Water ,URBANIZATION ,General Medicine ,PERFORMANCE ,Plants ,11831 Plant biology ,Beneficial microbes ,Field experiment ,SOIL - Abstract
On-site decentralized urban stormwater management has gained significant momentum in urban planning. Recently, vegetated roofs have been recommended as a viable decentralized stormwater management system and nature-based solution to meet the challenge of urban floods. However, as another type of unconventional green infrastructure, vertical greenery systems (VGS), also known as vegetated facades, have received much less research attention. Even though some researchers suggest that stormwater management by VGS is comparable to that of vegetated roofs, empirical evidence to substantiate this claim is limited. In this study, we conducted rain simulations on newly-built vegetation containers with water storage compartments. These vegetation containers were designed to be incorporated into a VGS specifically for stormwater management. We tested variables that could influence water retention efficiency and evapotranspiration of the containers under field conditions, i.e., inoculation of plant growth-promoting microbes (PGPMs) (Rhizophagus irregularis and Bacillus amyloliquefaciens), different substrate types (sandy loam and reed-based substrate), simulated rain quantity, natural precipitation, substrate moisture, and air temperature. The inoculation of PGPMs significantly reduced runoff quantity from the vegetation containers. Meanwhile, the well-ventilated sandy-loam substrate significantly reduced the remaining water in the water storage compartments over 1-week periods between rain simulation events, achieving high water-use efficiency. The selected microbes were established successfully in the containers and promoted the growth of 2 out of 5 plant species. R. irregularis colonization responded to substrate type and host plant species, while B. amyloliquefaciens population density in the substrate did not respond to these factors. Environmental conditions, such as antecedent substrate moisture, air temperature, and natural precipitation also influenced the efficiency of stormwater retention and/or evapotranspiration. In conclusion, this study provides instructive and practical insights to reduce urban flood risk by using VGS.
- Published
- 2022