Research & reports

Anne-Kristin Løes, Sebastian Eiter, Tatiana Rittl · Environmental Sciences Europe · Europe

Using soil data from ten peri-urban case farms near Oslo and Bergen, Norway, this study estimated how quickly potentially toxic element (PTE) concentrations would rise in soil under intensive application of compost or digestate from food waste, composted garden waste, or horse and poultry manure applied annually to meet a theoretical carrot crop's nitrogen, phosphorus and potassium demand. Under this intensive fertilization scenario, Norwegian soil quality limits for PTEs would be reached within 20-85 years, faster in soils with more organic matter, with limits reached first for copper and zinc, both essential micronutrients. The urban waste-based fertilizers were also found to be poorly balanced in macronutrients, with rates covering potassium demand leading to high phosphorus and nitrogen surpluses. The study concludes Norway's PTE regulations are stricter than the EU's and do not support recycling organic matter and nutrients from urban waste.

Myeong Seok Jeong, Mina Lee, Chaw Su Lwin, Kwon-Rae Kim · 한국토양비료학회지 · Korea (Jinju)

This study investigated heavy metal concentrations in soil and crop leaves from 23 urban gardens in Jinju, Korea, to assess suitability for cultivation. While average concentrations of As, Cd, Cr, Cu, Ni, Pb, and Zn generally did not exceed Korean guidelines, the Geoaccumulation Index indicated ongoing contamination by Cd, Cu, Pb, and Zn. A significant amount of Pb was introduced into some soils from the atmosphere, and continuous monitoring for heavy metals in urban garden soils is required for food safety.

Leigh Whittinghill, Major Ballard, Anju Chaudhary, Smriti Kandel, Caitlin Mullins, Pradip Poudel · HortScience · United States

This study analyzed runoff water quality from four different nutrient management treatments (conventional fertilizer, organic fertilizer, low-compost + organic fertilizer, and high compost) in raised beds and small plastic pool container plots in the United States. Water samples, collected monthly, were analyzed for pH, conductivity, color, turbidity, nitrate-nitrogen, ammonia-nitrogen, total phosphorus, and potassium. While significant differences existed between raised beds and container plots, these did not translate to meaningful water quality differences for most variables, except for nitrate-nitrogen. The conventional fertilizer treatment showed greater or more variable nutrient leaching than other treatments.

Michele D’Ostuni, C. Stanghellini, A. Boedijn, Leonardo Zaffi, Giuseppina Pennisi, Francesco Orsini · Sustainable Cities and Society · Netherlands (Amsterdam)

The feasibility of using urine and greywater streams as nutrient solutions in a theoretical model of Building-Integrated Agriculture in Amsterdam was evaluated. Results showed it is feasible to use urine and greywater as nutrient solutions; however, treated urine had higher macronutrient concentrations than literature fertilizer recipes, requiring dilution with increasing amounts of greywater to match N or P concentrations. Consequently, P deficiencies in plants or excessive N concentration were found in the final wastewater-based nutrient solution.

Jiangxiao Qiu, Hui Zhao · EDIS · Global

This overview identified eight ecosystem services generally attributed to urban agriculture, including food production, microclimate regulation, stormwater retention, and social-cultural values. However, the study found that quantitative evidence for many of these ecosystem services, especially intangible ones, is scarce. It suggests that while urban agriculture could be integral to green infrastructure, further consideration is needed for types, technology, management, and potential tradeoffs.

Iván Nocua, Karen del Pilar Galindez, J. Cordero, Astrid Del Pilar Ardila Bernal, Julián Serna, Omar David Guzmán, Cristian Fernando Camargo Muñoz, Mauricio Parra‐Quijano · Agronomía Colombiana · Colombia (Bogotá)

An urban garden was established within a greenhouse at the Universidad Nacional de Colombia, Bogotá campus, to investigate the effects of weeds and compacted soil in a biointensive approach. Over a two-month measurement period, 13 weed species were identified, with Veronica spp. being the most represented, and Poaceae family plants predominant within the orchard. While soil properties improved with the biointensive method and organic material addition, the presence of weeds highlights challenges and limitations in establishing urban gardens.

Bethaney Turner · · Global

This chapter explored human-soil relations in urban home and community gardens through ethnographic fieldwork. While biodiverse soil offers direct health benefits, the presence of contaminated, toxic soils, prevalent in lower socio-economic neighborhoods, was shown to expose inequities in access to safe gardening sites and hinder the realization of potential therapeutic benefits. It argues that the therapeutic benefits of gardens are best realized when humans cultivate attentive relationships with myriad multispecies companions.

Jordi Guimera Garcia, Natalie Bray, Yowhan Son, Aleah L. Butler-Jones, Sara Perl Egendorf, Jenny Kao‐Kniffin · Journal of Urban Ecology · United States (New York City)

In New York City, a study investigated plant growth (tomato, pepper, kale) in soils constructed from four municipal composts mixed with sediments from the NYC Clean Soil Bank, to assess the potential for safe urban agricultural soils. While Clean Soil Bank sediments enhanced plant growth when mixed with BRL compost, they also negatively impacted tomato aboveground biomass production by 29% in LES compost and tomato plant height by 18% in QBG compost, indicating variable effects depending on compost properties.

Abrham Kassa Ejigu, Kumelachew Yeshitela · Frontiers in Sustainable Cities · Ethiopia (Arba Minch City)

A study assessed Arba Minch City's governance capacity to integrate resource-oriented sanitation technology with urban agriculture. The findings indicated that the city's capacity is hindered by a lack of systematic monitoring, fragmented policy tools, and inadequate public sector participation. There is no single government body responsible for integration, and a behavioral gap exists among users in adapting to new technologies and recovered organic fertilizer.

Mahbuba Ferdous · Asian Journal of Advances in Agricultural Research · Australia (Armidale)

This case study investigated non-chemical weed management strategies in a small-scale vegetable garden in Armidale, Australia, through observation and an in-depth, unstructured interview with the garden's convener. Growers primarily used mechanical and cultural methods, including mulching, hand weeding, tillage, and grazing, to manage weed infestation. While mulching with wood chips and hand weeding were considered more effective in minimizing weed competition during critical crop development periods, they could not reach a satisfactory level. Further improvements by integrating several approaches simultaneously are needed for more effective and economical weed control.

Issaka Senou · Journal of Applied Biosciences · Burkina Faso

This study assessed heavy metal bioaccumulation in cabbage grown on the Dogona market garden perimeter in Bobo-Dioulasso, Burkina Faso, using a randomized block design with urban solid waste treatments. The results showed high levels of cadmium, copper, and lead in cabbage leaves, with concentrations significantly exceeding WHO standards across all treatments. A critical finding was that consuming this cabbage poses a high health risk to consumers due to significant ingestion of cadmium and lead.

Ane Novianty, Muhamad Nurdin Yusuf, Muhamad Arif Rizki Mauladi · MAHATANI Jurnal Agribisnis (Agribusiness and Agricultural Economics Journal) · Indonesia (Tasikmalaya)

This qualitative study explored the economic and environmental aspects of urban farming activities among 12 farmers in Kelompok Tani Taruna Tani Muara Hurip, Tasikmalaya City, Indonesia. The findings indicate that urban farming activities have not significantly contributed to the income of farmers or landowners, based on the investment ratio. However, environmentally, most farmers practice eco-friendly farming using organic fertilizers.

Aikaterini N. Martini, Μ. Papafotiou, Ioannis Massas, Nikoleta Chorianopoulou · Plants · Greece

Origanum dictamnus, a perennial herb endemic to Crete, Greece, was grown at two cultivation sites in Athens — an extensive green roof and ground level next to a moderate-traffic road — in two substrate types at 10 cm depth, to examine growth along with nutrient content (N, P, K, Na) and heavy metal accumulation (Cu, Pb, Ni, Mn, Zn, Fe) in its tissues. Plant growth was favored by the soil substrate but was also satisfactory in the soilless substrate. Cultivation site affected heavy metal accumulation, with higher concentrations found in leaves and flowers at street level, though no differences appeared in roots. Washing reduced heavy metal concentrations only in leaves grown at street level. Substrate type significantly affected manganese concentration in all tissues and iron concentration in roots, with the highest values in the soil substrate. The species could be cultivated on sustainable green roofs, preferably on a soilless substrate to reduce structural weight, but careful selection of the cultivation site was identified as necessary to minimize contamination with environmental pollutants when human consumption is intended.

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.

Sani Abubakar Mashi, Samuel Yakubu, Sofia Yuniar Sani · Asian Research Journal of Agriculture · Africa

A study in the Kubanni basin of Zaria, Africa, evaluated the quality of wastewater used for irrigating urban agriculture soils. The wastewater contained arsenic, iron, chromium, copper, zinc, manganese, and lead. Although concentrations were generally below Nigeria's permissible limits for irrigation, the study noted the metals' tendency to accumulate in soils, raising concerns about potential heavy metal buildup in irrigated soils and crops.

Myeong Suck Jeong, Mina Lee, Chaw Su Lwin, Kwon-Rae Kim · 한국토양비료학회지 · South Korea

This study investigated heavy metal contamination in urban agricultural soils near railway tracks and an industrial complex in Jinju, South Korea, to ensure food safety. While the average heavy metal values did not exceed soil contamination guidelines, some individual soil samples showed concentrations higher than the guidelines. Furthermore, the geoaccumulation index (Igeo) indicated that several soils were contaminated compared to background levels, with Cu, Pb, Zn, and Sb showing the highest contamination. Long-term monitoring of urban vegetable garden soils is recommended.

Ionat; id_orcid 0000-0001-9080-2282 Zurr, Oron; id_orcid 0000-0002-2893-5364 Catts · UWA Profiles and Research Repository (University of Western Australia) · Australia

The "Sunlight, Soil & Shit (De)Cycle" project, presented by SymbioticA in February 2022, is a performative experiment exploring agricultural technology (AgTech) and its aim to remove natural elements like sunlight, soil, and organic waste from food production. This project considers whether the precursor to sustainable food systems will be the creation of a metabolic rift, where the means of production grow ever distant from nature. It highlights a critical environmental tradeoff by questioning the separation of humans from nature in technological farming.

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).

Jianyun Nie, Akira Kiminami, Hironori Yagi · Sustainability · China (Shanghai)

This study analyzed the sustainability status of 22 urban leisure farms in Shanghai using the IDEA method. Farms' average sustainability scores were 25.72 on the agroecological scale, 32.5 on the socioterritorial scale, and 46.5 on the economic scale. This analysis revealed that while urban leisure agriculture in Shanghai has high sustainability at the economic scale, its overall sustainability was low, indicating a need for further strengthening.

Jihan Faouzi, Imane Bedoui, Sanae Rezouki, Tarik Moubchir, Aimad Allali, Noureddine Eloutassi, Amal Lahkimi · Ecological Engineering & Environmental Technology · Morocco (Fez)

This study in Fez, Morocco, compared bacteriological and parasitological contamination in urban, peri-urban, and rural irrigation waters, and their transfer to soil and crops (cardoon and eggplant). Investigated microorganisms included total and thermotolerant coliforms, helminth eggs, Salmonella, and cholera vibrio. Results revealed contamination exceeding national and international standards for both types of coliforms in treated wastewater (TWW), wastewater (WW), Oued Fez water, and upstream well water in both winter and summer. This fecal contamination was found in soils and crops irrigated by urban and peri-urban water. Helminth eggs and cholera vibrio were also present in these waters, soils, and crops, with Salmonella detected in TWW in summer. Only the plot irrigated with Oued Bitit water in the rural zone met standards across all three levels of irrigated water, soil, and plants, and in both periods.

Shiyu Cui, Wenbin Liu, Hexian Jin, Yi Qiao, Ying Wang, Dan Liu · Atmosphere · Global

This study investigated the effects of mixed cropping garden plants (Festuca arundinacea, Ageratum conyzoides, Trifolium repens) with Brassica parachinensis on Cr-contaminated soil remediation. While mixed cropping with Trifolium repens resulted in the highest B. parachinensis yield and Cr content below standard in edible parts, mixed cropping with Ageratum conyzoides aggravated Cr pollution in edible parts of B. parachinensis, making it unsuitable for planting.

Muhammad Sarjan, M. Taufik Fauzi, Ruth Stella P. Thei · Unram Journal of Community Service · Indonesia (Mataram City)

This action research in Mataram City during the COVID-19 pandemic introduced Integrated Pest Management (IPM) practices to urban farming groups. Group discussions revealed that while participants were interested in developing fresh vegetables and fruits and found benefits in meeting family food needs, most members were unfamiliar with environmentally friendly cultivation techniques, particularly IPM.

Anna Paltseva, Zhongqi Cheng, Murray B. McBride, Maha Deeb, Sara Perl Egendorf, Peter M. Groffman · Frontiers in Ecology and Evolution · Global

This synthesis paper summarizes current scientific knowledge on lead (Pb) contamination in urban garden soils and provides clear recommendations for assessing actual health risks and limiting exposure. Urban garden soils often contain elevated levels of Pb, mainly from legacy sources, which is a main barrier for urban gardening. Amendments are noted as unreliable for treating contaminated soils to reduce risk, as they do not always make contaminants less harmful.

Monika Egerer, Brenda B. Lin · CABI Reviews · Global

This review evaluated ecosystem services (ES) within urban agriculture (UA) systems and the trade-offs between these services. Urban agriculture provides many benefits and environmental services such as food provision, social cohesion, and climate regulation. However, it was shown that management decisions can create trade-offs between ecosystem services, where an increase in one service may potentially reduce the system's ability to provide another service at a desired level.

Nini Sané, Malick Mbengué, Amandine Laffite, Serge Stoll, John Poté, Philippe Le Coustumer · Water · Global

This study developed a wastewater treatment plant prototype coupled with Moringa oleifera seeds to reduce fecal indicator bacteria and antibiotic-resistant bacteria in domestic wastewater. The prototype alone reduced bacteria by 99.34%. The addition of Moringa oleifera seeds achieved high removal rates for E. coli (36.6–78.8%), fecal coliform (28.3–84.6%), Vibrio cholera (35.3–95.6%), and total flora (32.1–92.4%). For antibiotic-resistant bacteria, removal rates were up to 98% for E. coli and fecal coliform, 100% for Vibrio cholera, and 91.96% for total flora.