Research & reports

Kinga Kimic, Magdalena Błaszczyk · Sustainability · Poland (Warsaw)

This study identified and assessed vegetable cultivation projects submitted to the Warsaw Participatory Budget (WPB) between 2015 and 2023. The research classified projects into six types and evaluated them across social, functional, ecological, and economic dimensions. The results showed that vegetable-related projects in the WPB were decidedly niche, with only 101 initiatives submitted and 31 implemented, primarily focusing on education for children rather than direct food access.

Marta Melon, Tomasz Dzieduszyński, Piotr Sikorski, Beata Joanna Gawryszewska, Maciej Lasocki, Arkadiusz Przybysz · Sustainability · Poland (Warsaw)

The capacity of Family Allotment Gardens (FAGs) in Warsaw, Poland, to provide air-pollution filtration and microclimate regulation was quantified. Particulate matter, air temperature, and relative humidity were measured inside and outside three allotment complexes in autumn 2023. Results showed a moderate reduction in PM concentrations inside gardens (by about 2 µg/m³) and slightly higher humidity (2.1%). However, the cooling effect was weak (less than 0.3 °C), indicating a limited spatial range under autumn conditions.

Ayhan Horuz, Güney Akınoğlu · · Turkey

A Turkish book chapter arguing that agriculture-derived air pollution, compounded by growing industrial and urban pollutant loads, is threatening food production, product quality, and food security by directly and indirectly impairing plant growth and development. It notes that population growth, energy production, transportation, waste management, and biomass burning have substantially increased atmospheric organic and inorganic pollutants, pushing air quality beyond acceptable limits in many regions. The first part evaluates the effects on agroecosystems of tropospheric (ground-level) ozone, PM2.5 and PM10, nitrogen oxides (NOx), sulfur dioxide (SO2), agricultural ammonia (NH3), and volatile organic compounds (VOCs), detailing how tropospheric ozone suppresses photosynthesis causing yield losses in staple crops such as wheat and soybean, and how particulate matter directly and indirectly affects soil and plant health, alongside the effects of acid rain and nitrogen deposition on soil fertility, water quality, and ecosystem balance, assessed against the four pillars of food security—availability, access, utilization, and stability. The second part discusses integrated policy approaches, industrial emission control technologies, and low-emission transport systems at the macro level, alongside agricultural strategies such as precision farming, improved fertilizer management, and innovative production techniques, and the role of green infrastructure in urban planning.

Evangelista et al. · Agronomy for Sustainable Development · Europe

This 8-year case study tracked tomato cultivation in a rooftop greenhouse. Peak yield reached 49 g plant−1 day−1 in the 2023 cycle, but overall yield declined by 31.2% across the 8 years. Best water use efficiency reached 36.8 g/L under reduced irrigation. Solar transmittance dropped from 50.9% in 2015 to 46.4% in 2023 due to polycarbonate degradation, and life-cycle global warming impact rose from a minimum of 0.54 kg CO2eq to 0.94 kg CO2eq in 2023.

Juliane Forßmann, Simon Goebel · Zeitschrift für Flüchtlingsforschung · Germany

An urban gardening project in a residential facility for up to 230 refugees in Germany aims to counteract precarious living conditions. While the garden offers a low-threshold space for knowledge exchange on resource-saving cultivation, biodiversity, and health promotion, this paper also reflects on the project's limits.

Corina Başnou, Geovana Mercado, Åsa Ode Sang, Thomas B. Randrup, Verónica Fabio, Adrián Cabezas, Arnau Lluch, Marc Montlleó, Juan Miguel Kanai, Riccardo Saraco, Olívia Bina, Tom Wild · Nature-Based Solutions · Europe

An overview and guidance for air pollution indicators in nature-based solutions (NBS) for urban green planning and public health were provided, using three case studies in Europe and Latin America. The study noted that approaches including multidimensional indicators in research, planning, and policies are limited, and national standards for some air pollutants are missing with little evidence for health effect thresholds. Findings also indicated that knowledge of pollutant uptake in edible plants can suggest potential human exposure risks.

Mais Jafari, Rolf Morgenstern, Jonas Runte · · Germany

This chapter analyzed the co-creation pathway of Nature-based Solutions (NBS) in the Dortmund Living Lab, focusing on urban gardening, food forests, and biodiversity. It critically illustrated missing dimensions that hinder innovation, such as business opportunities, legal frameworks, and planning conditions. These identified gaps indicate challenges in governance and implementation for social innovation through NBS.

Javier Rodrigo-Ilarri, Claudia P. Romero-Hernández, Sergio Salazar-Galán, María-Elena Rodrigo-Clavero · Sustainability · Spain (Valencia)

This article analyzes the impact of urban sprawl on the Valencia Plain aquifer system from 1990 to 2018 using the Weighted Environmental Index (WEI). Results show urban surfaces expanded by 70% and rainfed agricultural areas declined by over 59%, leading to a 9.2% reduction in environmental value (WEI decreased from 44.80 to 40.68). These changes threaten ecosystem sustainability and reduce the capacity to deliver ecosystem services.

Ágnes Gagyi · Local Environment · Europe

This paper investigated urban gardening in an East European capital, focusing on institutional resources. The study found a clear relationship between a shortfall of institutional resources and the limited, conflictual promotion of urban gardens as sustainability tools. It argues that gardens' contradictions stem from the privatization of public functions, which has depleted institutions capable of implementing gardens as sustainability tools, instead outsourcing costs to garden communities.

Sergi Ventura, J.R. Armengol Miró, David Camacho-Caballero, Enric Casellas, Ricard Segura-Barrero, Alberto Martilli, gara villalba · Urban Climate · Spain (Barcelona)

This study used the Pseudo Global Warming method and WRF model to assess urban heat adaptation strategies in the Metropolitan Area of Barcelona. Three strategies were evaluated: increasing rooftop albedo, implementing irrigated sedum green roofs, and increasing peri-urban agriculture and urban parks. While increasing rooftop albedo provided the greatest daytime cooling (−1.75 °C), and green roofs and peri-urban agriculture showed moderate regulation, none of the strategies fully counterbalanced the projected 6 °C temperature increase by 2100, indicating a limited capacity of these adaptations under severe warming scenarios.

Ricard Segura, Johannes Langemeyer, Alba Badía, Sergi Ventura, Jaime Vila-Traver, Gara Villalba · The Science of The Total Environment · Spain (Barcelona)

A study in the Metropolitan Area of Barcelona, Spain, investigated the impacts of peri-urban agricultural expansion on the food-water-climate nexus using urban metabolism and atmospheric-biosphere models across four land-use scenarios. While expansion increased food production and irrigation water requirements, replacing natural non-forested and forest areas for peri-urban agriculture was predicted to reduce net ecosystem productivity by up to 18.5% and total carbon stocks by 3.3%. Irrigated peri-urban agriculture potentially reduced near-surface temperatures by 0.7°C, though reductions in the densest urban areas were minimal.

Holger Braun, Dorothee Apfel, Benedikt Rilling, Carsten Herbes · Cleaner and Responsible Consumption · Germany

A study with 44 hobby gardeners in Germany found that substrates are not a major part of gardeners' social interactions, and price is the dominant purchase criterion for substrates, with sustainability not playing an important role. Although basic knowledge about peat is widespread, purchasing substrates is a utility-driven process with mostly passive information behavior.

Jaume Vilasís Pamos, Pablo Aránguiz, Stefhania Lozano, Guillermo Palau Salvador · Revista Lecciones Vitales · Spain (Valencia)

This study examines urban agriculture initiatives in Valencia, Spain, which adopt an agroecological approach to promote sustainable practices like composting. While these collective strategies aim for sustainable agricultural models and contribute to food sovereignty, they face significant challenges, particularly regarding access to water. The initiatives also engage in political action and promote equitable organizational models.

Alberto Matarán-Ruiz, David Fanfani, Josefa Sánchez Contreras, Miguel Ángel Escalona Aguilar · · Central America; Europe

This chapter examines bioregional food systems and territorialization processes in peri-urban agricultural areas, using three case studies from Central America and Europe. It notes that the historical co-evolutionary relationship between cities and surrounding farmlands weakened in modernity due to the global capitalist market, which reduced food to a commodity. The study highlights current problems while exploring how inherited relationships are being revived to adapt urban bioregions to climate emergency and resource scarcity.

Lara Houston, Sara Heitlinger, Ruth Catlow, Alex Taylor · Policy Press eBooks · United Kingdom (London)

Workshops critically experimented with the possibilities and challenges of blockchain as an infrastructure for food abundance and reparative work, using fictional scenarios set in a London transformed into a city farm by 2025. This experimentation suggested that blockchain presents challenges to such restorative and sustainable work. For participants, reparation involved working in the aftermath of social and environmental collapse to bring into being more-than-human-value systems that radically decentered human knowledge and experience.

Silvio Caputo, Victoria Schoen, Chris Blythe · Land · United Kingdom (London)

Data was collected from seven community gardens and one community farm in London, UK, during the 2019 and 2020 growing seasons using a citizen science approach, investigating crop yield, resource inputs, and social benefits. Results showed very mixed levels of crop and social productivity depending on organizational structure and agenda, with no clear pattern emerging. This study suggests that citywide productivity evaluations based on small data samples may not be reliable.

Runrid Fox-Kämper, Caitlin K. Kirby, Kathrin Specht, Nevin Cohen, Rositsa T. Ilieva, Silvio Caputo, Victoria Schoen, Jason K. Hawes, Lidia Poniży, Béatrice Bechet · Landscape and Urban Planning · Europe; United States

The relationship between urban agriculture (UA) and food-energy-water (FEW) nexus policies was analyzed using policy data from five case study cities in Europe and the U.S. (Dortmund, Gorzów Wielkopolski, London, Nantes, and New York City). An analysis of 78 policy documents and a Q-sort ranking by UA policy experts showed that the number, type, and degree of support for nexus policies varied among cities, and few policies (19) incorporated all elements of the nexus. Regulations were considered more effective at ensuring resource-efficient UA than incentives or awareness-raising policies.

Mahir Yazar, Ece Baykal Fide, İrem Daloğlu Çetinkaya · Journal of Environmental Policy & Planning · Turkey

A 2023 study of climate policies in nine cities in Turkey examined how vulnerable groups and individuals are identified and how land-use policy is developed to address the identified vulnerabilities and climate justice concerns, using policy content analysis and expert interviews. The analysis found critical relationships between identified vulnerable groups, responsive land-use policy and climate justice. While social-aid municipalism-related vulnerabilities dominated districts' climate policies, nature-based solutions (NBS) — especially green infrastructure and urban agriculture — emerged as the dominant climate adaptation approach. However, the way urban vulnerabilities are prioritized in the climate and sustainability plans places less emphasis on intersectionality and infrastructure-related vulnerabilities, and tokenism of justice occurs in the policy documents: the plans do not incorporate vulnerable communities into land-use planning. The study concludes that the complexity of responsive land-use policy requires greater awareness of how to practically support vulnerable communities.

Angelica Mendoza Beltrán, Kelzy Jepsen, Martí Rufí-Salís, Sergi Ventura, Cristina Madrid‐López, Gara Villalba · The Science of The Total Environment · Spain (Barcelona)

This study mapped N2O emissions from peri-urban agriculture in the Metropolitan Area of Barcelona (AMB), Spain. Researchers spatially distributed factors like crop type, fertilizer use, and irrigation, creating N2O emission maps using crop-specific and Tier 1 IPCC emission factors (EFs). The study found that Tier 1 IPCC EFs estimated 15% more emissions (7718 kg N2O-N year−1) than crop-specific EFs (6533 kg N2O-N year−1) for the entire AMB, indicating higher emissions for rainfed crops with Tier 1 EFs and for irrigated horticultural crops with crop-specific EFs. The mapping helps evaluate spatial variability of key factors but carries uncertainties due to downscaling regional data.

Elizabeth Regier, Walter McDonald · Journal of Sustainable Water in the Built Environment · United States (Milwaukee)

This study monitored two bioswales treating runoff from an urban farm in Milwaukee, WI, United States, to assess their hydrologic and water quality performance. The bioswales effectively reduced runoff volume, peak flows, total phosphorus, and high concentrations of total suspended solids (TSS >25 mg/L), achieving a median 98% load reduction across all pollutants. However, they showed mixed results in reducing total nitrogen concentrations and TSS at low influent concentrations (≤25 mg/L).

Angelica Mendoza Beltrán, Roc Padró, María José La Rota-Aguilera, Joan Marull, Matthew J. Eckelman, Jacob Cirera, Annalisa Giocoli, Gara Villalba · The Science of The Total Environment · Spain (Barcelona)

This study implemented an attributional, regionalized, cradle-to-gate life cycle assessment (LCA) to assess 14 environmental impacts of peri-urban agriculture (peri-UA) in the Metropolitan Area of Barcelona (AMB). It found that vegetables and greenhouses, the prevalent peri-UA land uses, had the largest assessed impacts among all peri-UA land uses. European NPK mineral fertilizer production to cover nitrogen demand for these crops drives all impacts. For fruit crops, on-site nitrogen emissions drive marine eutrophication impacts, and for irrigated herbaceous crops, phosphate runoff drives freshwater eutrophication impacts.

Petr Klusáček, Stanislav Martinát, Klára Charvátová, Josef Navrátil · Land · Europe

This study investigated the drivers of de-agrarianization in post-socialist cities, using Brno, Czech Republic, as a case study through qualitative interviews. It found procedural issues in preserving architectural heritage during the redevelopment of a former Cistercian monastery site, often resulting in only fragments being preserved. The research also demonstrated a decline in the use of urban agricultural properties, which are rapidly transformed into new urban environments under intense urbanization pressures.

Ambrogio Zanzi, Valentina Vaglia, Roberto Spigarolo, Stefano Bocchi · Land · Italy (Milan)

This study assessed the sustainability of eight agri-food start-ups in a peri-urban area of Milan, Italy, using the FAO's Sustainability Assessment of Food and Agriculture systems (SAFA) framework. The application of SAFA indicators revealed positive aspects but also some limitations typical of unstructured enterprises.

Friederike Reents · Publication Server of the Catholic University Eichstätt-Ingolstadt (Catholic University of Eichstätt-Ingolstadt) · Germany

This paper analyzes Thomas Kling’s poem „geschrebertes idyll, für mike feser“ as an "allotment garden idyll" within 'new nature poetry'. While Kling skillfully engages with the idyll genre and offers ecological, social, medial, and historical critique, the study finds that he presents a decidedly patriarchal self-image, which contemporary readers would likely find less acceptable.

Sandra Schwindenhammer, Denise Gonglach · Politics and Governance · Germany

This qualitative and participatory case study in Germany examined the governance implications of an emerging technology in urban agriculture that connects wastewater treatment and agricultural production for urban hydroponics. The analysis found that while this technology has the potential to facilitate SDG implementation, it simultaneously creates new sector interlinkages between water and food, leading to policy demands that necessitate more integrated policymaking.