Research & reports

Julio César García-Colin, Carlos Díaz-Delgado, Humberto Salinas-Tapia, Carlos Roberto Fonseca, María Vicenta Esteller Alberich, Khalidou M. Bâ, Daury García-Pulido · Water · Spain

Using lysimeter data from a golf course in Spain, researchers designed and validated a sustainable urban agriculture drainage system with water reuse (SUADS-WR) based on a daily water balance, estimating reference evapotranspiration via the Penman-Monteith or Hargreaves-Samani methods. Compared with experimental data, estimated irrigation depths were lower than the water actually supplied, and estimated percolation matched measured field drainage. Implementing SUADS-WR allowed harvested water to cover more than 38% of the crop's annual water demand.

Verónica Arcas‐Pilz, Xavier Gabarrell, Francesco Orsini, Gara Villalba · The Science of The Total Environment · Europe

A literature review mapped technologies for recovering nitrogen (N) and phosphorus (P) from urban waste sources for use in urban agriculture (UA), distinguishing (1) food, organic and biowaste sources, for which 7 recovery strategies were identified, from (2) wastewater, for which 11 were identified, and assessed the potential for the metropolitan area of Barcelona. Recovering nutrients through composting and anaerobic digestion of organic waste, composting of wastewater sludge, struvite precipitation and ion exchange in wastewater effluent could, depending on the strategy, meet current and prospective UA phosphorus demand 2.7 to 380.2 times over and nitrogen demand 1.7 to 117.5 times over. Despite this technical potential, the review concludes that current perceptions, legislation and implementation and production costs relative to existing markets do not facilitate the actual application of these nutrient recovery strategies.

Ministère de la Transition écologique · Ministère de la Transition écologique (France) · France

France's Ministry of Ecological Transition's official page on the mandatory source-sorting of biowaste (food and garden waste). Per EU law and France's 2020 anti-waste law, source-sorting became mandatory nationwide for all professionals and households from January 1, 2024. Biowaste is described as making up one-third of unsorted household waste; the government's 'Fonds vert' has supported local authorities' sorting infrastructure since 2023.

Eugenio-Gozalbo M., Ramos-Truchero G., Suárez-López R., Romanillos M.S.A., Rees S. · Education Sciences (MDPI), 12(3):168 · Europe

A study assessing a garden-based teaching unit on 'Food and Nutrition' against a traditional textbook-based unit. The garden-based sequence produced more comprehensive student understanding and better preparation for real-life dietary decisions, representing an educational improvement over traditional teaching.

Tripodi P., D'Alessandro A., Francese G. · Frontiers in Plant Science 13:1031776 · Italy

Integrated genomic and biochemical analysis of heirloom tomatoes linking fruit shape and size to sugars, organic acids, and aroma compounds. Demonstrates heirlooms as germplasm resources for high food quality and sustainable agriculture.

· Frontiers in Microbiology · Germany (Berlin)

Investigated how soil microbial communities shift along an urban gradient in Berlin, highlighting that microbial communities inhabiting urban soils govern nutrient cycling and support of plant communities.

Schittko C. · Journal of Ecology · Germany (Berlin)

Shows that biodiversity maintains soil multifunctionality and soil organic carbon in novel urban ecosystems studied in Berlin.

Rüschhoff J., Hubatsch C., Priess J., Scholten T., Egli L. · Renewable Agriculture and Food Systems · Germany (Leipzig)

A Leipzig case study assessing food self-sufficiency potential, finding that combining organic agriculture, reduced food loss, and a more plant-based diet could reach a mean self-sufficiency level of about 95%.

Ducasse V., Capowiez Y., Peigne J. · Agronomy for Sustainable Development · France (review)

Reviews the suitability of vermicomposting the organic fraction of municipal solid waste, the quality of the resulting vermicompost, and its impact on crops and soil.

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.

Wim van Dijk, J.E. Jansma, J. Broeze, J.J.R. Groot · · Netherlands (Amsterdam)

This chapter focuses on regional resourcefulness for food systems, arguing that urban areas are vital for closing nutrient loops to prevent resource depletion. Two case studies in the Metropolitan Region of Amsterdam (MRA) discuss phosphorus (P) flows, exploring the potential of a circular food system in Almere and quantifying actual P-flows across the MRA. The chapter concludes that a circular City Region Food System is technically feasible but requires a fundamental shift in the organization of food and waste systems.

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).

M.C.G. Haitsma Mulier, F.H.M. Van de Ven, Paul Kirshen · Energy Nexus · Netherlands (Amsterdam), United States (Boston)

This study quantified the Water Energy Nutrient Food (WENF) nexus for three urban farms: a greenhouse in Amsterdam, and a community farm and a container farm in East-Boston. It investigated the water, energy, and nutrient demands of these farms and the availability of resources in urban waters. The study found that the water and nutrient demands (nitrogen and phosphorus) of all three farms could be met by local urban water resources, but energy availability depended on the type of agriculture.

Kimo van Dijk, Lotte Veenemans, Ciska Nienhuis · · Netherlands (Amsterdam)

This report explains the importance of improving sanitation circularity, its link to circular urban food production, and the opportunities and barriers for its realization in Amsterdam. It discusses aspects related to sustainability, environment, quality, agronomy, legislation, health and safety, technology, economics, and awareness. The report provides recommendations for Amsterdam and other cities to stimulate the transition to circular sanitation and nutrient recovery/reuse in urban agriculture, including clarifying legislation and addressing barriers.

Concepción Santiago Cubas, Concepción Paredes Gil · Modern Environmental Science and Engineering · Spain

A study on Gran Canaria, Spain co-composted municipal and agricultural plant residues with three manure types — chicken, goat and cow — in an open dynamic windrow system of three trapezoidal piles (1.5 m high, 2.5 m wide, 16 m long), mixed at 37.6% straw, 32.7% manure and 29.7% pruning residue by fresh weight. Temperature, humidity and physico-chemical parameters were tracked through the process. All three piles reached the sanitation threshold required by regulation (≥60°C for at least 7 days) and produced compost suitable for agricultural use.

· Water · Germany (Berlin)

Analyzes the causal relations of upscaled urban aquaponics with the food-water-energy nexus, using Berlin as a case study.

Miriam C. Dobson, Philip H. Warren, Jill L. Edmondson · Sustainability · United Kingdom

This nationwide citizen science project investigated resource demands of urban horticultural production in the United Kingdom using year-long diaries from 163 allotment gardeners. Findings showed an average allotment required 87 annual visits and 139 km of travel. Each kilogram of food produced used 0.4 hours of labor, 16.9 L of water, 0.2 L of topsoil, 2.2 L of manure, and 1.9 L of compost.

Erik van den Elsen, P.F.A.M. Römkens, S.J.E. Verzandvoort, G.W. Korthals, Dorothee Leenders -van Tol, J. Bloem · · Netherlands (Amsterdam)

This report selects relevant soil quality indicators for assessing soil quality in the Amsterdam metropolitan region, specifically for 'urban agriculture' and 'urban green' applications. It notes that while agricultural soil quality indicators exist, specific ones for urban environments were lacking. A case study in Amsterdam's 'Fruittuinen van West' area develops an example for using these indicators in urban agriculture.

Michelle Brener Mizrahi · European Journal of Cultural Management and Policy · Europe

This paper analyzes how Incredible Edible Todmorden (IET), a community-led project, operated notions of sustainability through permaculture and urban farming to focus on community building and its impacts on education and local culture. The paper puts forth the argument that the discursive operationalization of sustainability can produce important effects in community building, education, and local culture at a local level.

Ambrogio Zanzi, Federico Andreotti, Valentina Vaglia, Sumer Alali, Francesca Orlando, Stefano Bocchi · Sustainability · Italy (Milan)

This study aimed to assess the benefits of an agroecological requalification of a dismissed peri-urban area in the South Milan Agricultural Regional Park, Italy. Using I-Tree Eco software, the provision of ecosystem services from planting new hedgerows was simulated over 30 years, showing that the planted area becomes an essential supplier of regulating ecosystem services for neighborhoods, increasing carbon storage and air pollution removal. A notable increase in carbon sequestration was observed at the end of the simulation, demonstrating a replicable methodology and techniques for assessing ecosystem services in urban and peri-urban environments.

Felipe Parada, Xavier Gabarrell, Martí Rufí-Salís, Verónica Arcas‐Pilz, Pere Muñoz, Gara Villalba · The Science of The Total Environment · Spain (Barcelona)

This study investigated the agronomic performance and environmental life cycle impacts of three different fertigation management practices (open, 30% recirculation, and recirculation with a further 15% fresh water reduction) for tomato crops in a rooftop greenhouse in Barcelona. All three practices resulted in similar yields, but the recirculation with reduced fresh water input was the most water-efficient, requiring 48.7 liters per kg of tomato. In terms of environmental performance, the recirculation practice showed the best performance in most impact categories, particularly in marine and freshwater eutrophication, with 44% and 93% fewer impacts than the open management.

Cecilia Herbón, María Teresa Barral, Remigio Paradelo · Applied Sciences · Spain (Santiago de Compostela)

The concentrations of trace elements Cu, Pb, Zn, Ni, Cr, and As were investigated in 55 urban soils in Santiago de Compostela, northwestern Spain. While most soils showed higher trace element concentrations than regional backgrounds, they were not classified as contaminated according to Spanish regulations. However, geoaccumulation index values indicated low to moderate pollution levels in most soils, with Cu, Pb, and Zn highest in city center green areas, and Cr and Ni linked to parent material lithology.

Felipe Parada, Mireia Ercilla‐Montserrat, Verónica Arcas‐Pilz, Elisa López‐Capél, N. Carazo, J.I. Montero, Xavier Gabarrell, Gara Villalba, Joan Rieradevall, Pere Muñoz · Journal of the Science of Food and Agriculture · Spain (Barcelona)

In spring and summer 2018, in a rooftop greenhouse near Barcelona, coir, vegetable compost from urban organic waste, perlite, and a mixture of compost and perlite substrates were evaluated over three consecutive crop cycles of lettuce. This study aimed to assess the use of substrates made from local materials as an alternative for urban agriculture during periods of water supply cuts. Results showed that compost and the mixture yielded similarly to perlite, and organic substrates increased crop resilience to water restriction.

Sovová L., Veen E.J. · Sustainability (MDPI), 12(12):5134 · Europe

A comparative study of food self-provisioning in allotment gardens in the Netherlands and Czechia, drawing on social practice theory. It argues self-provisioning is neither merely a poverty response nor a trend, holding significant potential for food provisioning that can be supported within alternative food networks and urban sustainability frameworks.

Richter S., Haase D., Thestorf K., Makki M. · Urban Forestry & Urban Greening · Germany (Berlin)

First study combining soil and tree carbon stocks for Berlin to estimate its carbon storage potential, finding soils account for more than two-thirds of the city's stored organic carbon.