Green roof substrates—A literature review

Abstract

Green roofs are becoming increasingly popular in urban construction due to their wide array of benefits for creating a sustainable ecosystem. Many stakeholders invest in green roofs in the 21st century to enhance the environmental quality and mitigate urban ecological pollution. The substrate layer is the most important and critical component of green roof systems. The objective of the review study is to present the important information regarding the required elements that need to be considered for substrate selection of green roofs by critically reviewing the scientifically published articles. Research findings from past studies relevant to green roofs, vegetation and selective substrate parameters were extensively discussed under different topics related to water retention, drought resistance and related physico-chemical parameters. The generalities in past research articles were presented and special focus was provided on specific research articles those presented novelty regarding green roof substrates. Furthermore, the hotspots in all the considered research articles were commentatively identified and the appropriate solutions were evaluated. The critical review of published research articles indicates that most of the research on green roof substrates was conducted in either controlled laboratories or greenhouses and did not provide much importance to actual field tests. Therefore, these research findings are not sufficient to obtain the realistic field outcomes of the research. Future studies on green roof substrates should need to incorporate field experiments along with classical controlled tests by adhering to standard guidelines for assimilating climatic influences in substrates. Few studies have focused on dry climates, and further research needs to be conducted on dry climates due to their high susceptibility to drought and evapotranspiration. This manuscript would be the first review article that mainly focuses on substrates for green roofs, which is a novel aspect.

Feasibility study for estimating optimal substrate parameters for sustainable green roof in Sri Lanka

“…The projection of EC into arithmetic equation facilitates the researchers to find EC magnitudes for corresponding substrates at an arbitrary temperature within the experimental range. This approach resolves the inferences from room temperature fluctuations (Kader et al, 2022), atmospheric pressure (Ono & Mibe, 2015), and related environmental conditions (Figs. 10 and 11).…”

“…Since sawdust (60:40) has exhibited the closest pH value to 7.0, it is recommended as the most compatible substrate species among the selected contenders, in terms of pH. A substrate with a neutral pH of 7.0 is recommended to create optimum conditions for vegetation in substrate (Kader et al, 2022 ). In rational perspective, the substrate with a pH magnitude closest to 7.0 was decided to be proposed as the best growing medium for species in terms of pH.…”

“…The physicochemical and biological properties described within the scope of this experimental study have substantially influenced the results exhibited by each substrate candidates. One of the main defect in terms of green roof related research studies are the lack of field experiments since most of the studies are based on laboratories and greenhouses (Gougoulias et al, 2013 ; Kader et al, 2022 ). This experimental study has provided a feasible solution for this concern by providing a pioneer experimental framework in this article which incorporates physicochemical and biological parameters with 10 types of laboratory and field experiments.…”

“…Saturated media extract (SME) technique is suitable to find the absolute EC of specimens (Huang et al, 2006 ) but consumes a great deal of time (Kader et al, 2022 ). Plug sensors methods are not preferred here since they are highly compatible with homogenous solutions (dos Santos Sousa et al, 2021 ; Visconti & de Paz, 2016 ).…”

Soil Management in Sustainable Agriculture: Analytical Approach for the Ammonia Removal From the Diary Manure

“…The phenomena of organic nitrogen hydrolysis in cattle manure induce ammonia (NH3) production during ammonification (Abendroth et al, 2015). Conventional methods like denitrification are mainly focused on biological treatments to remove nitrogen by converting it into nitrogen gas (Kader et al, 2022). Since this method is not applicable to raw cattle manures, modern methods like Struvite precipitation (Uludag-Demirer et al, 2005), Gas-Permeable membrane (Filho et al, 2018;Vanotti & Szogi, 2010), Alternative Stripping Reactors (Filho et al, 2018), chemical amendments (Kavanagh et al, 2019), by using chemical acidifier, commercial products and agricultural waste (Kavanagh et al, 2021) and biofilter (Shang, et al, 2021) were successfully used in past research to recover ammonia from the extracted solid manures and slurries.…”