Research & reports

Raquel Yurie Hioki, Moacir Roberto Darolt · Archives of Veterinary Science · Brazil (Curitiba)

This study, conducted in Curitiba, Brazil, and its metropolitan area, aimed to discuss the risks and benefits of legalizing urban poultry farming. Through interviews with key informants, challenges were identified across sanitary, legislative, and commercial areas, urban chicken breeders, and bird management. The main challenges cited were sanitary and environmental risks, mistreatment, irregular slaughter, and neighborhood disturbances, which could be addressed through activity regulation, registration of farms, technical monitoring, and implementation of pilot projects.

Anne-Louise Fritz, Ramia Jannoura, René Beuschel, Christoph Steiner, Andreas Buerkert, Rainer Georg Joergensen · Chemical and Biological Technologies in Agriculture · Africa

This 2-year study in semi-arid Ouagadougou and sub-humid Tamale, West Africa, measured the effects of biochar and N fertilization on soil microbial biomass carbon, fungal ergosterol, and functional diversity. Sole biochar addition did not affect soil chemical or biological properties, but biochar with N fertilization increased microbial respiratory response. N fertilization decreased soil pH by 1.1 units in both cities, and a pH of 4.7 led to reduced microbial biomass carbon and ergosterol contents in Tamale. An N fertilizer-induced decline in soil pH below 5 should be avoided, as it decreased microbial biomass carbon and microbial functional diversity.

Paulien C. H. van de Vlasakker, Karin Tonderski, Geneviève S. Metson · Frontiers in Sustainable Food Systems · Global

A review of empirical peer-reviewed studies (2000-2021) on nutrient losses to water from soil- and ground-based urban agriculture. Of 241 publications screened for a stated concern with nutrient losses to water, 20 were retained, but only seven had actually measured losses to water. Of four experimental studies, three measured leachate losses under different garden management practices; of 16 real-world studies, only four quantified losses to water as leachate, with measured average losses ranging from 0.005 to 6.5 kg/ha for phosphorus and 0.05 to 140 kg/ha for nitrogen. Thirteen of the 16 non-experimental studies provided input and harvested-crop data allowing nutrient balances to be calculated; despite wide value ranges, most studied gardens showed nutrient surpluses (inputs exceeding crop harvest) for nitrogen and phosphorus but not potassium, identified as a risk factor for losses to water, though large surpluses were not always linked to higher leachate losses. The review concludes that more field studies measuring actual losses to water, and documenting contextual factors, are needed to determine whether urban agriculture can contribute to a circular economy without causing nutrient-related water quality impairment.

James D. Blount, Leah E. K. Lenoch, Faith A. Fitzpatrick · Journal of Great Lakes Research · United States

A study of Apple Creek, Wisconsin (119 km²), a Great Lakes tributary like many others subject to Total Maximum Daily Load (TMDL) targets requiring reductions of 51.2% in suspended sediment and 64.2% in total phosphorus. From August 2017 to October 2018, an integrated stream sediment budget and fingerprinting study quantified upland and stream-corridor sources of suspended sediment and sediment-bound phosphorus. Phosphorus concentrations varied among source groups and fluvial sediment types, with higher concentrations in suspended sediment and cropland soils. Eroding streambanks accounted for 100% of the TMDL model's (SWAT) suspended sediment load but only 20% of the total phosphorus load; fine-grained streambed sediment equated to roughly three years of modelled suspended sediment load but only one-third of the total phosphorus load. The two primary sources of fine-grained streambed sediment were streambanks and cropland, with the relative streambank contribution increasing downstream and with watershed area. The relative proportion of suspended sediment varied by season and streamflow, but weighted for representative streamflow, cropland and streambank erosion accounted for 54% and 23% of suspended sediment respectively. Urban land was a source in the upper watershed, but its signature was sequestered by a mid-watershed detention basin, and contributions from construction sites were higher in fall 2018, likely corresponding to increased activity following a wet spring.

Hae Jong Yang, Tae‐Woo Kang, Byungwoong Choi, Soon Hong Hwang, Dongseok Shin, Won-Pyo Park · Sustainability · South Korea

This study verified heavy-metal pollution levels in sediments of an urban-agricultural watershed in the Yeongsan River basin, South Korea, through evaluation of Sediment Quality Guidelines (SQGs), a pollution load index (PLI), and a potential ecological risk index (PERI), and analyzed statistical relationships between pollution levels, land use, and potential pollution sources. Pb, Zn, Cu, Cd, and Hg concentrations were highest at mid-upstream sites, while As, Cr, and Ni concentrations were similar across most sites. Sites showing potential toxicity to benthic organisms relative to SQGs were most frequently observed at mid-upstream, and PLI and PERI evaluations likewise confirmed high anthropogenic pollution and ecological risk there. Mid-upstream sites with high heavy-metal pollution correlated strongly with urban land use — the largest land-use category — indicating links to population density and industrial complexes; statistical analysis confirmed this relationship. The findings indicate that urban areas are highly likely to cause anthropogenic heavy-metal pollution of sediments via point and non-point sources such as domestic sewage and industrial wastewater.

Alba Canet-Martí, Rocío Pineda‐Martos, Ranka Junge, Katrin Bohn, Teresa A. Paço, Cecília Delgado, Gitana Alenčikienė, Siv Lene Gangenes Skar, Gösta F. M. Baganz · Water · Global

This paper examines nature-based solutions (NBS) for urban agriculture (UA) in circular cities, focusing on input/output streams. It identifies that the understanding of I/O streams for different NBS is insufficient to fully leverage their potential for strengthening circularity in UA. The study pinpoints gaps that hinder UA's development as an opportunity within the Circular City framework, emphasizing the need for a broader understanding of food-related urban streams.

Yang Deng · Journal of Hazardous Materials Letters · Global

While rainwater harvesting (RWH) is considered a sustainable irrigation method for urban agriculture, contaminants in rainwater pose challenges to RWH practices due to potential threats to crop, soil, and human health. Based on literature data, principal pollutants such as particles, toxic metals like cadmium, copper, and zinc, synthetic organic chemicals like agrochemicals and polycyclic aromatic hydrocarbons, and waterborne pathogens were identified as likely exceeding irrigation quality criteria. This study identifies challenges, knowledge gaps, and research needs for RWH irrigation, offering a basis for technical strategies.

Isaac Asirifi, Korbinian Kaetzl, Steffen Werner, Courage Kosi Setsoafia Saba, Felix K. Abagale, Philip Amoah, Bernd Marschner · Journal of Environmental Quality · Ghana

A field experiment in northern Ghana assessed health risks from pathogen and heavy metal contamination in urban agriculture, evaluating rice husk biochar, N-P-K fertilizer, and their combinations with untreated wastewater or tap water irrigation. While heavy metals in irrigation water and soil were below FAO/WHO standards, wastewater irrigation caused significant E. coli, fecal coliform, and helminth egg contamination on red amaranth vegetables and in soil. Biochar application did not affect bacterial contamination.

Luciano Majolo, Deibson Teixeira da Costa, Camila Firmino de Azevêdo · Editora Científica Digital eBooks · Global

This study analyzed the application of fresh coffee grounds as a substrate for arugula seed germination, using concentrations of 0% to 25%. All evaluated characteristics, including emergence percentage, seedling length, and mass, showed a decreasing variation with increasing coffee grounds. Fresh coffee grounds applied directly as fertilizer proved inefficient for arugula in the tested quantities.

Mary Njoki Mwaura, Sabina Mukoya-Wangia, Japheth Ododa Origa, O.L.E. Mbatia, Evans Chimoita · Journal of Agricultural Extension · Kenya

A study of 149 respondents in Nairobi County examined urban and peri-urban agricultural practices, finding composting and open field farming popular but not the most profitable. More profitable practices like cattle rearing and mushroom farming were unpopular due to expensive inputs and specialized skills. The study indicates that popular practices are less profitable, highlighting a need for transformation towards controlled environment agriculture with policy support.

Ahmed Khadra · IGI Global eBooks · Global

This chapter examines the health effects of climate change, specifically focusing on the global issue of fecal peril caused by intestinal parasites. It suggests that water shortages, driven by climate change, increase pressure on water resources, leading to greater use of urban wastewater for irrigation in urban agriculture. Unsafe management and inappropriate wastewater use are likely to exacerbate the transmission of infectious diseases, including those caused by intestinal protozoa and helminths.

Dong BaoCheng, Wei Li, Wenyong Xu · Antibiotics · China

A field experiment in peri-urban agricultural soil in China investigated the effects of partially substituting chemical fertilizer with organic fertilizers like pig manure and sewage sludge on soil quality and antibiotic residues. Organic substitution significantly increased residual antibiotic levels in agricultural soil, with antibiotic sequestration rising by 138.1~332.5%. This indicated that organic fertilizers can promote antibiotic persistence in soil by modifying soil quality, demonstrating a contamination risk.

Francis Mwanza, Erick Komba, Dominic Kambarage · International Journal of Microbiology · Tanzania (Dar es Salaam)

This study in Dar es Salaam, Tanzania, investigated the occurrence, antimicrobial resistance, and genetic relatedness of E. coli isolates from 156 samples of manure, vegetables, and fish. Of these, 36 samples (23.1%) were positive for E. coli, yielding 48 isolates. A significant finding was that 25 (52.1%) of these isolates were resistant to at least one antimicrobial agent, and 12 (48.0%) showed multidrug resistance, indicating a potential microbial health risk to humans through contamination.

Solomon Tulu Tadesse, O. Oenema, Christy van Beek, Fikre Lemessa Ocho · Frontiers of Agricultural Science and Engineering · Ethiopia

This study in Jimma, Ethiopia, from 2015-2050, used an N mass flow model and field experiments to explore manure recycling from urban livestock farms under four scenarios. It found that livestock manures are the main organic wastes in urban areas, and manure production in urban and peri-urban agriculture (UPA) is projected to increase 3 to 10 times. Critically, only 13% to 38% of manure nitrogen will be recycled in croplands, and intensification of urban livestock production greatly increased nitrogen surpluses, indicating a significant environmental tradeoff.

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.

Zachary Burt, C. Shambu Prasad, Pay Drechsel, Isha Ray · Journal of Water Sanitation and Hygiene for Development · India (Karnataka)

A preference-ranking model was developed to understand the acceptance of fecal sludge-derived fertilizer (FSF) in Karnataka, India, by modeling farmowners and farmworkers separately. The study found that farmers willing to use FSF prefer to conceal its origins from workers and their caste group, especially caste-adhering, vegetarian farmowners. Workers were open to FSF if it resembled cow manure, revealing that the waste economy in rural India is shaped by unacknowledged caste hierarchies and practices.

Rafael Carvalho Machado, Sieglinde Kindl Da Cunha · Waste Management & Research The Journal for a Sustainable Circular Economy · Brazil (Curitiba)

This study investigated Curitiba, Brazil's Urban Agriculture Program (UAP) and its decentralized composting strategy, which aimed to close the agricultural loop within city bounds. Despite training 24 urban farmer communities in composting techniques, the program was unable to achieve this goal. The research, based on secondary data review, interviews, and participatory observation, identified cultural barriers and conflicts among actor roles within the UAP that hindered the adoption of composting practices.

Maha Deeb, Peter M. Groffman, Manuel Blouin, Sara Perl Egendorf, Alan Vergnes, Viacheslav Vasenev, Donna L. Cao, Daniel C. I. Walsh, Tatiana Morin, Geoffroy Séré · SOIL · Global

This review examines the use of Constructed Technosols (CTs), mixtures of organic and mineral waste, for green infrastructure (GI) in urban spaces. While CTs have high potential to provide multiple soil functions and contribute to urban greening, urban soils are often physically, chemically, or biologically unsuitable for GI features. The analysis suggests that the composition and structure of CTs should be adapted to available wastes and by-products, as well as future land use and environmental conditions, highlighting the need for careful design to overcome existing limitations.

Ali Keyvanfar, Arezou Shafaghat, Tan Sze Inn, Sapura Mohamad · DigitalCommons - Kennesaw State University (Kennesaw State University) · Malaysia

This research developed the Sustainable Urban Farming Index Assessment (SUFIA) Model to quantify and evaluate the performance of urban farms' sustainable food production. Applying a critical literature review and Analytical Hierarchy Process (AHP), the model identified reducing air pollution, soil health and water cleaning, and food sovereignty as critical for food productivity. When implemented at Zenxin Organic Farm in Malaysia for validation, the farm earned a Grade C, indicating it is a usable urban farm but requires substantial improvements in areas such as soil health, water cleaning, site design, and community environment.

Maëlle Tripon, Dorothée Boccanfuso, Marie-Ève Yergeau · Cahiers de recherche · Global

This literature review examines urban agriculture (UA) models, their implementation contexts, production needs, and impacts. It highlights that UA faces limitations, particularly restricted access to good quality (unpolluted) soil, water, and air, which can negatively impact productivity. UA can also have negative impacts on ecosystems and human health, such as pollution and diseases, depending on management methods.

John Taylor · Frontiers in Sustainable Food Systems · United States (Rhode Island)

This long-term replicated trial in Rhode Island evaluated the yield performance and soil quality impacts of four small-scale food production systems over three summer growing seasons. While total marketable food yields (2.22 to 2.96 kg m-2) were modest compared to biointensive agriculture (4.64 kg m-2), individual crop yields often exceeded regional and national averages without soil quality loss. The study addresses a lack of experimental research on urban agriculture and provides a framework for normative research, offering more reliable yield estimates for modeling urban production potential.

Noiry Pérez Pompa, Santa Laura Leyva Rodríguez · Sinergia Académica · Cuba

A diagnosis of farms infested by Dichrostachys cinerea (marabú) in urban and suburban agriculture was conducted at Los Téllez farm in Becerra, Las Tunas municipality, Cuba. Soil quality indicators for reddish-brown Fersialitic soils over granitoids were evaluated across four land-use systems: two infested by D. cinerea and two agricultural systems cultivated for 10 years after marabú deforestation. Results showed that D. cinerea systems exhibited the highest soil quality index, based on organic matter, bulk density, and earthworm biomass. Conversely, cultivated systems achieved the lowest accumulation of organic carbon, oligochaete density and biomass, and total porosity.

Martí Rufí-Salís, Felipe Parada, Verónica Arcas‐Pilz, Anna Petit‐Boix, Gara Villalba, Xavier Gabarrell · Frontiers in Plant Science · Spain (Barcelona)

This study investigated a closed-loop crop cascade system in a Barcelona rooftop greenhouse, using tomato leachates to irrigate five successive lettuce cycles. The results showed that low yields (below 130 g per lettuce plant) were obtained when the cascade system was used during the early stage of the donor crop, as the nutrient amount, especially nitrogen, was insufficient for the receiving lettuce crop. Additionally, electrical conductivity values became too high (near 3 dS/m) at the end of the donor crop cycle, indicating limitations in maintaining optimal conditions throughout.

Bruce G. Ferguson, Helda Morales · · Mexico (Chiapas)

The Laboratorios para la Vida action research team in Chiapas, Mexico, trains educators to use school gardens and local food systems as venues for experiential learning. However, teachers face a host of hurdles to successful garden programs, including high teacher turnover, lack of space, and the difficulty of matching garden growth with the national curriculum calendar.

Govinda Prasad Devkota, Sheri Lee Bastien, Petter D. Jenssen, Manoj K. Pandey, Bhimsen Devkota, Shyam Krishna Maharjan · International Education Studies · Nepal

This Participatory Action Research study in Nepal investigated five teachers' perceptions of using urine diversion dry toilets (UDDTs) and human urine as fertilizer in school gardens. Few teachers accepted human urine as fertilizer, considering it impure and expressing unwillingness to use it on crops. Teachers disliked UDDTs due to perceived bad odor and uncomfortable sitting positions, especially for females, and felt urine as fertilizer was unnecessary.