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

Abstract

In twenty-first century buildings, green roof systems are envisioned as great solution for improving Environmental sustainability in urban ecosystems and it helps to mitigate various health hazards for humans due to climatic pollution. This study determines the feasibility of using five domestic organic wastes, including sawdust, wood bark, biochar, coir, and compost, as sustainable substrates for green roofs as compared to classical Sri Lankan base medium (fertiliser + potting mix) in terms of physicochemical and biological parameters associated with growing mediums. Comprehensive methodologies were devised to determine the thermal conductivity and electric conductivity of growing mediums. According to preliminary experimental results, the most suitable composition for green roof substrates comprised 60% organic waste and 40% base medium. Sawdust growing medium exhibited the highest moisture content and minimum density magnitudes. Biochar substrate was the best performing medium with the highest drought resistance and vegetation growth. The wood bark substrate had the highest thermal resistance. Growing mediums based on compost, sawdust, and coir produced the best results in terms of nitrate, phosphate, pH, and electric conductivity (EC) existence. This study provided a standard set of comprehensive comparison methodologies utilising physicochemical and biological properties required for substrate characterization. The findings of this research work have strong potential in the future to be used in selecting the most suitable lightweight growing medium for a green roof based on stakeholder requirements.

Influence of cultivar and fertilization treatment on the yield and leaf nutrients content of apple (Malus domestica Borkh.)

“…As a perennial crop, apple requires balanced nutrition for growth, optimum yield, and quality of fruit. An optimum supply of nutrients from the soil to the plant system also aids pathogenic resistance, and the longevity of vegetation [ 4 ], and increases the stability and quality of seedlings [ 5 , 6 ]. The key micronutrients for sustainable growth of apple plant species are include B, chlorine, copper, Fe, Mn, molybdenum, sodium, selenium, and Zn, which are required in minute amounts [ 7 ].…”

“…The fruit tree does not consume a large portion of the nutrients given, which might contaminate the soil and groundwater [ 12 ]. Throughout the years, usually unregulated, the excessive, and continuous use of mineral fertilisers has resulted in a significant negative impact on the production efficiency and quality of apple fruits, as well as the physicochemical and biological properties of soil [ 4 , 13 , 14 ].…”

Key Barriers and Feasibility of Implementing Green Roofs on Buildings in Malaysia

“…A green roof can be described as a structural system incorporating different layers (such as waterproofing, drainage, soil, and vegetation) installed on top of a standard roof. The two main types of green roofs are extensive and intensive [6,9,10]. Extensive green roofs offer several advantages over intensive ones, including lower capital and maintenance costs and reduced water requirements.…”

“…Similarly, in subtropical and tropical regions, the implementation of green roofs offers a compelling scenario that intertwines environmental benefits with unique challenges stemming from the distinct climatic and ecological characteristics of these areas [6]. In these warm and often humid climates, the adaptation of green roofs can significantly transform urban landscapes while improving environmental problems [12,13] and addressing critical sustainability concerns, such as incorporating recycled waste materials into the design [3,10]. Green roofs provide a promising solution for temperature regulation in subtropical and tropical regions, where temperatures consistently lean toward the warmer spectrum.…”

“…The presence of vegetation acts as a natural insulator, helping to cool indoor spaces and reducing the reliance on energy-intensive air conditioning systems. As a result, green roofs contribute to improved energy efficiency [7,14,15] and promote more sustainable urban development [10]. Moreover, green roofs effectively combat the urban heat island (UHI) effect [7,16] that often plagues subtropical and tropical cities.…”