Research & reports

Rattan Lal · · Global

A book chapter addresses rising food and nutritional insecurity from rapid urbanization in Sub-Saharan Africa, South Asia and elsewhere, noting that 55% of the world population currently lives in cities, projected to reach 70% by 2050. It states that as much as 10-20% of food consumed could be grown within city limits, but that careful planning is needed to reduce risks from soil contamination, plastic pollution, and reuse of grey/black water and city-waste compost. It identifies rooftop gardens, multistory glass buildings, and soil-less methods such as aquaculture, hydroponics and aeroponics as modern forms of urban agriculture, and discusses barriers including land tenure and research priorities for scaling up.

Joan Casanelles-Abella, Monika Egerer · Frontiers in Sustainable Cities · Global

A perspective article discusses biodiversity conservation in cities as often afflicted by "suboptimal" situations where human needs and nature's needs are imbalanced or in conflict. In human-dominated landscapes, land use intensification often replaces large habitat patches critical for metapopulation stability with smaller, isolated patches, a pattern Island Biogeography Theory predicts will reduce biodiversity; this may be most extreme in cities experiencing rapid population growth and infrastructure densification, where small urban green spaces, balconies, home and allotment gardens, small forest patches and green walls, become the primary compensatory interventions for retaining habitat. However, under certain conservation frameworks (land-sparing vs. land-sharing, the SLOSS debate), such small, scattered urban green spaces may be predicted to produce suboptimal or even detrimental biodiversity outcomes if their size and isolation prevent them from sustaining viable population sizes. The article notes this "ecology of suboptimals" framing risks a futile perspective on nature conservation in densifying cities, while also considering how rethinking urban environments in light of this situation might be approached.

Daniel Etim Jacob, Imaobong Daniel Jacob, Koko Sunday Daniel, Pius Agaji Oko · Sustainable Food Connect · Global

A paper arguing that recreational planning in the Global South is constrained by Western models prioritizing ornamental aesthetics over local socio-ecological crises, producing metabolically inefficient and exclusionary landscapes, and proposing an "Agro-Blue Commons" (ABC) framework integrating food production, sustainable water management and communal leisure. The framework was tested through a qualitative meta-synthesis of four prototype cases in Lagos, Mumbai, Rajasthan and Nairobi, purposively sampled to represent diverse biomes and climate-vulnerable informal settlement types, evaluated with a Multi-Criteria Assessment focused on metabolic circularity, governance polycentricity and socio-spatial accessibility. Results show that integrating food, water and leisure together with polycentric stewardship increases urban resilience and reduces resource dependency, while the paper states that systemic change requires addressing institutional inertia and insecure land tenure to prevent speculative displacement of marginalized communities.

Patrick Sobotka · reposiTUm (TU Wien) · Austria

Set against growing urban populations, housing shortages, and ecological and social challenges, this TU Wien thesis is a design study exploring housing that supports urban agriculture through integrated vertical farming. Its aim was to develop a hybrid housing concept combining sustainable timber construction with vertical farming, using a modular timber structure intended to offer ecological benefits, short construction times, and the ability to add stories later without sealing new land. The project centers on compact apartments for young adults, students, and couples, drawing on literature review of sustainability, timber construction and vertical farming, plus analysis of selected reference projects, to produce a design concept. No quantitative evaluation results are reported.

Sasha Gillies-Lekakis, Heidi Zogbaum · International Journal of Cuban Studies · Cuba

Cuban historiography is typically divided into pre-1959 and post-1959 periods, but land-use practices show continuity across both. Two hundred years of export-oriented sugar planting left Cuba dependent on food imports, first from the United States and later the Soviet Union. After 1991, Cuba had to find ways to feed itself on land depleted by two centuries of monoculture. The introduction of permaculture — first developed in Australia and suited to urban agriculture — helped Cubans address some of these food supply problems, making Cuba a world leader in permaculture practice.

Abhijeet Das, Satchidananda Mishra · Green Technology Resilience and Sustainability · Global

This study develops a conceptual and analytical framework for embedding circular-economy and zero-waste principles into hydroponic agriculture systems worldwide, using system mapping, resource-flow analysis, and indicator structuring to compare linear, partial-recirculation, and near-zero-discharge configurations. The analysis found that continuous nutrient recirculation and controlled dosing improve resource retention, and that system stability increases when buffering capacities across water, nutrient, and energy subsystems are aligned; capacity balance and feedback control were identified as key determinants, though the work is conceptual, without empirical field validation.

Akhil S Anand, Hannes Pravida, Fredrik Fossan-Waage, Tormod Skorpe Skjolden, Giulia Robbiani, Younes Zahraoui, Emil Wolff Anthony, Jayaprakash Rajasekharan, Sissel Torre, Knut Asbjørn Solhaug, Sebastien Gros · Frontiers in Horticulture · Global

A paper on vertical farming — a controlled-environment agriculture system — examines its potential integration with energy markets. It states that vertical farming's economic viability is constrained by high capital and operational costs, a substantial share of which is energy expenditure, and explores how vertical farms could participate in day-ahead, balancing, and flexibility energy markets by adjusting lighting and climate-control energy use in response to market signals, potentially reducing costs and generating additional revenue. It identifies gaps in understanding of plant responses to variable lighting as a critical barrier to implementation and illustrates these integration challenges through small-scale laboratory experiments.

Agure E, Kihagi GW, Muok EMO, Sorgho R, Danquah I · Journal of Health, Population and Nutrition · ケニア・シアヤ郡

A qualitative study of a home gardening intervention in Siaya county, rural Kenya, undertaken because home gardens are promoted as a climate change adaptation strategy in sub-Saharan Africa but the lived experience of them is less documented. Between September and November 2023 the authors ran two focus group discussions with stakeholders (n = 5) and implementers (n = 8), plus 30 in-depth interviews with male (n = 5) and female (n = 25) beneficiaries, using purposive sampling and semi-structured guides; data were transcribed verbatim and analysed by inductive content analysis mapped along the proposed impact pathways. Participants articulated a good understanding of the trainings and valued them as an occasion for knowledge exchange, and the adoption of tailored garden structures, organic gardening and food preservation created feelings of fulfilment, women's empowerment and family peace. Challenges included water scarcity, ineffective pesticides and long distances between beneficiary households. Perceived benefits were increased income, cost savings and increased dietary diversity.

Md. Nur Alom Sarkar Mithun, Saifur Rahman, Md. Asifur Rahman, Md. Hasan Sabit, Joseph L. Donaldson, Shonia Sheheli · Urban Agriculture & Regional Food Systems 11(1) · Bangladesh (Mymensingh — Kewatkhali and Aqua)

A study of perceived barriers among 100 randomly selected rooftop gardeners in Kewatkhali and Aqua, Mymensingh, Bangladesh, interviewed with a structured protocol between September and November 2023 and analysed with descriptive statistics, rank order, correlation coefficients and multiple linear regression. Every participant perceived substantial barriers. The most prominent concern was the complexity of the technologies involved; neighbours' negative attitudes ranked least significant. Age, rooftop garden area, income, experience, contact with extension media and gardening knowledge were all negatively and significantly related to perceived barriers, with garden area and knowledge the strongest predictors in the regression. The authors argue that research, demonstrations, extension activity and training to build residents' skills and understanding are the way to lower those barriers.

· Wikipedia · Global

This article describes green roofs as roof structures covered with vegetation and growing media that provide stormwater retention, insulation, urban heat island mitigation, and biodiversity benefits. Installation costs vary widely by system type, from $108-248/m2 for extensive systems to $355-2,368/m2 for intensive systems, with long-term economic benefits such as extended roof lifespan and increased property value offsetting high upfront costs.

· Wikipedia · Cuba

This Wikipedia article covers Cuba's 'Special Period' economic crisis following the Soviet Union's collapse. Oil imports fell to about 10% of pre-1990 levels, GDP shrank 35%, and imports and exports both fell over 80%. Agricultural production fell 47%, construction fell 75%, and manufacturing capacity fell 90%, driving the need for agricultural transformation.

· Wikipedia · Global

This Wikipedia article on the Haber (Haber-Bosch) process for industrial ammonia synthesis states that, as of 2018, the process produced 230 million tonnes of anhydrous ammonia per year, and that 'nearly 50%' of the nitrogen found in human tissues originated from it. Ammonia production is said to account for 1-2% of global energy consumption, 3-5% of natural gas production, and 3% of global carbon emissions, while nitrogen use efficiency is typically less than 50%, with farm runoff from excess use disrupting biological habitats. The article also credits the process with supporting global population growth from about 2 billion in the early 20th century to over 8 billion today.

· Wikipedia · Global

This Wikipedia article on nitrogen fixation (the chemical process converting inert nitrogen gas into biologically usable nitrogen compounds) states that, as one legume example, nitrogen fixation by red clover can range from 50 to 200 lb/acre (56 to 224 kg/ha). It states the marine cyanobacterium Trichodesmium is thought to account for 'almost half' of nitrogen fixation in marine systems globally, and that the amount of nitrogen fixed in the ocean is at least as much as on land. It also credits the spread of Haber-process nitrogen fertilizer with helping expand the human population from about 2 billion in the early 20th century to over 8 billion today.

· Wikipedia · Global

The Wikipedia article on compost describes it as a mixture used as plant fertilizer that improves soil's physical, chemical and biological properties, made by decomposing plant/food waste and manure. It requires four elements — carbon, nitrogen, oxygen and water — with an optimal carbon-to-nitrogen ratio of about 25:1. About 20% of landfill waste is compostable material such as food, and composting reduces methane emissions compared to landfilling organic material.

· Wikipedia · Global

A Wikipedia article on terra preta, a fertile anthropogenic dark soil found across the Amazon Basin, formed between 450 BCE and 950 CE and rich in low-temperature charcoal and pottery shards. It notes black carbon content reaching up to 9% (versus 0.5% in surrounding soils), depths of up to 2 meters, a regeneration rate of about 1 centimeter per year, an estimated coverage of 0.1-0.3% (6,300 to 18,900 square kilometres) of the Amazon Basin, and modern biochar-based attempts to recreate it.

· Wikipedia · Global

Soil is a complex three-phase system of minerals, organic matter, gases, water, and organisms that supports plant growth and soil life. A typical soil is about 50% solids (45% mineral, 5% organic matter) and 50% pore space, with microbial density around 10^8 organisms per gram and pore-space CO2 concentrations 10 to 100 times atmospheric levels.

· Wikipedia · Global

Soil compaction is a geotechnical process that removes air between soil particles under stress, increasing density. It is essential as a support layer in construction but reduces water infiltration and root growth in agriculture. The degree of compaction is assessed relative to maximum dry density determined by tests such as the Proctor test; the article presents no specific numeric data.

· Wikipedia · Global

Rainwater harvesting (RWH) is a long-standing technique for collecting rainwater from roofs and other surfaces into tanks or reservoirs, used worldwide for water supply in water-scarce areas, flood mitigation, and cost savings. Frankfurt Airport's system saves about 1 million cubic meters of water per year, Mumbai has mandated RWH infrastructure for new buildings above certain sizes since 2002, and typical UK households can reduce water use by 20-30% through RWH.

Teerlinck J., Dewaelheyns V., Wittemans K., Tzoulas K., Raymaekers P., Cavan G., Steen T., Somers B. · Urban Forestry & Urban Greening · Belgium (Flanders)

A paper on domestic gardens in Flanders, Belgium, examining how gardens are used, what they are composed of, and what stands in the way of climate change adaptation in them — treating the privately-held share of urban green space as an adaptation resource. Note: this entry is written from the paper's bibliographic record and title; see the article itself for its figures and conclusions.

Ceccanti F., Bischi A., Desideri U., Baccioli A. · Energy Conversion and Management · 国際比較（トロンハイム・上海・ドバイを想定したモデル計算）

Filling a gap left by studies that assessed vertical-farming energy use and cost-effectiveness with simplified models, this paper isolates how individual input parameters drive efficiency, sustainability and economic viability using a detailed modelling framework with sensitivity and correlation analyses. It evaluates 162 scenarios combining three levels of temperature, photosynthetic photon flux density (PPFD) and CO2 concentration across the socio-environmentally distinct Trondheim, Shanghai and Dubai regions, at two insulation thicknesses. Because of HVAC and dehumidification, crop productivity stays optimal regardless of insulation or external climate. PPFD dominates growth (correlation 0.85), ahead of CO2 (0.36) and temperature (0.22), and also drives energy consumption (0.73). Lowest specific energy consumption coincides with lowest productivity (55 kg/m2), and the cheapest levelized cost of lettuce came at 24 degC, 250 umol/m2s PPFD, 1400 ppm CO2 with insulation (102 kg/m2). Only decarbonised energy systems can support vertical farming without raising CO2 emissions relative to imported lettuce.

Haoqiu Lin, Xun Li · Sustainability · Global

This systematic review synthesizes peer-reviewed literature on various forms of green infrastructure and their mechanisms for mitigating Urban Heat Island (UHI) effects, and the function of urban green spaces (UGS) in reducing the impact of UHI. Important mechanisms, including shade, evapotranspiration, albedo change, and ventilation, were investigated in connection with urban parks, green roofs, street trees, vertical greenery systems, and community gardens. The findings show that green areas, including parks, green roofs, and street trees, can lower air and surface temperatures by as much as 5 °C. However, the efficiency of cooling varies depending on plant density and spatial distribution.

Annamaria Alabiso, Giorgio Buratti, Fiammetta Costa, Matteo Meraviglia, Luciana Migliore, Attilio Nebuloni · · Global

A transdisciplinary research project investigated reusing treated kitchen wastewater for irrigating edible vegetable production in households. The project developed a prototype with an engineered biological filter to reuse dishwasher wastewater for growing vegetables and ornamental plants for domestic use. This approach aims to reduce water and fertilizer consumption, enabling the production of healthy, safe, and local food.

Piaopiao Ke, Beñat Olascoaga, Pasi Kolari, Outi Tahvonen, Sami Haapanala, Tom Kokkonen, Leena Järvi, Markku Kulmala, Anna Lintunen · Urban forestry & urban greening · Finland

A year-round eddy covariance and soil chamber measurement in an urban allotment garden in southern Finland showed it functioned as a net CO₂ source (0.69 kg m⁻² yr⁻¹) despite 77% vegetation cover. High respiratory emissions (4.7 kg m⁻² yr⁻¹) exceeded photosynthetic uptake (4.0 kg m⁻² yr⁻¹), likely due to elevated soil organic carbon (13.4 ± 8.7%) and high soil C:N ratio from management amendments. These findings challenge assumptions about urban gardens as inherent carbon sinks and suggest carbon-smart management practices are needed.

Shanurasab K Nadaf, VR Yadahalli, Bebijan Nadaf · International Journal of Advanced Biochemistry Research · Global

This review explores the motivations and practical strategies for growing food in small urban spaces, addressing challenges like limited space and poor soil. It discusses techniques such as vertical gardening, container planting, hydroponics, and raised beds, along with crop selection and resource optimization. The article also examines challenges, success stories, and the role of technology in making urban gardening accessible.

Chua Siu Ting, Hazreena Hussein · Journal of Surveying Construction & Property · Malaysia (Port Dickson)

This study explored residents' perceptions of social spaces in Port Dickson, Malaysia, during the COVID-19 pandemic, using a mixed-method approach combining photographic documentation and a questionnaire survey. The majority of respondents experienced significant stress during the pandemic due to anxiety, job loss, and livelihood challenges, emphasizing the importance of effective space allocation and varied options within residential neighborhoods. These findings imply that strategically designed social spaces and zoning practices are key to developing self-sufficient communities in residential areas.