Outdoor living wall systems in a developing economy: A prospect for supplementary urban food production?

Green wall systems have greatly advanced over the past few decades and hold important potential for the future in light of predicted urban population growth, densification, and climate change. This article provides a brief background to living walls, followed by a summary of the advantages and disadvantages of the four types of systems that are currently available in South Africa. It makes use of a case study review of three recently implemented edible living walls in Gauteng to reflect on the challenges currently experienced and the future potential benefits, with specific focus on system resilience, economic feasibility, and edible plant possibilities. Interviews were conducted with clients and client representatives, contractors and/or designers on each project. The findings suggest that living walls have indirect commercial value through customer experience and satisfaction, as well as educational value. Should the scale, economic feasibility and resilience of living wall systems be enhanced, they can improve urban food production. The article concludes that this could be achieved in the Global South by using simplistic technologies with lower cost living wall infrastructure systems. When deployed on a large scale, with climate-tolerant indigenous and edible plants in exterior systems, productivity will be improved.

A Review of Urban Green and Blue Infrastructure from the Perspective of Food-Energy-Water Nexus

Small scale urban green-blue infrastructure (indicated as GBI hereafter) comprises huge underexploited areas for urban development and planning. This review article aims to highlight the relevance and knowledge gaps regarding GBI from the perspective of the food–energy–water (FEW) nexus, these being key resources for the survival of human communities. In particular, this review was focused on publications on urban ecosystem services (positive effects) and dis-services (negative effects) associated with different GBI typologies. The review proved that GBI can contribute environmentally, socially, and economically to FEW security and urban sustainability. Yet, such positive effects must be considered against ecosystem dis-services tradeoffs, including urban food production, commonly connected with heavy water and energy consumption, specifically under dry climate conditions, and sometimes related to an excessive use of manure, pesticides, or fertilizers. These conditions could pose either a risk to water quality and local insect survival or serve enhanced mosquito breeding because of irrigation. Up to now, the review evidenced that few nexus modeling techniques have been discussed in terms of their benefits, drawbacks, and applications. Guidance is provided on the choice of an adequate modeling approach. Water, energy, and food are intrinsically associated physically. However, depending on their management, their tradeoffs are often increased. There is a need to minimize these tradeoffs and to build up synergies between food, energy, and water using a holistic approach. This is why the FEW nexus approach offers good insights to address the relation between three important individual resource components of sustainability.

HEAVY METALS IN FOOD CROPS: IDEAL SOURCES AND ROLES OF URBAN AGRICULTURE IN FACILITATING THEIR CONSUMPTION- A REVIEW

The qualities of agricultural soil and water are diminishing continuously due to the rigorous anthropogenic activities currently stocking the soil with a lot of toxic chemicals including heavy metals. Heavy metals are highly persistent and non-biodegradable, control of their contamination is very tricky to handle. Their presence in soil and water is detrimental to food crops and humans. Various sources of heavy metals contaminants and the role of urban food production on human heavy metal contamination were discussed.Heavy metals have their way into the soil and food crops through wastewater irrigation and production in contaminated soil. The habitual heavy metals contamination sources for food crops are wastewater irrigation, abuse of agrochemicals, production in the contaminated field, atmospheric deposit when foods are exposed to contaminated air, and unethical mining activities. Agricultural soil in urban and peri-urban areas are heavily contaminated with heavy metal due to various anthropogenic activities. Wastewater irrigation intensify the contamination by supplying the soil with more heavy metals. The heavy metals are passed to food during production and subsequently to humans after consumption.

Introduction to the Special Issue “A Systemic Perspective on Urban Food Supply: Assessing Different Types of Urban Agriculture”

The production of food within cities through urban agriculture can be considered as a nature-based solution and is argued to be an important response to the current COVID-19 pandemic as well as to climate change and other urban challenges. However, current research on urban agriculture is still fragmented, calling for a systematic and integrative assessment of different forms of urban agriculture and the drivers and constraints for their effective realization. In this context, the Special Issue presents conceptual and empirical research articles from around the world on the impact and implementation potential of various types of urban agriculture. The studies of this Special Issue cover a broad range of impact and implementation dimensions, asssessment methods and geographical backgrounds that can support future studies to develop a systemic perspective on urban food production.

SUSTAINABILITY AND DEVELOPMENT OF AQUAPONICS SYSTEM: A REVIEW

The world is facing soil, air and water pollution problems which may arise the soil degraded, global warming, food shortage and droughts. For our future generations we have to develop sustainable environment technologies. Many studies have addressed some scientific aspects and have been limited focus on the commercial implementation based on urban food production industrial-scale production in rural areas small scale farming is developed in different countries for education and decoration inside buildings. We must encourage the sustainable small farming as indoor fish farming which is the farming of the new millennium aquaponic is a structure of closed-loop combine the elements of hydroponics and aquaculture which could contribute the addressing these problems. This system emphasis on improvement through management and integration of the living components and the bio filter system. From trickling bio filters and plant uptake of aquaculture wastewater results in improved water and nutrients use efficiency and conversation. The challenge to sustainability centers on balancing the aquaculture system environment for the optimum growth of these organism’s maximum production outputs and minimize effluent discharges to the environment emission and might develop the future application of aquaponic for food security.