Research & reports

John Taylor, Sarah Taylor Lovell, Sam E. Wortman, M.K. Chan · Renewable Agriculture and Food Systems · United States (Chicago)

In Chicago, semi-structured interviews and plant inventories were conducted with 59 African American, Chinese-origin, and Mexican-origin households regarding ecosystem services and tradeoffs in their home food gardens. A total of 387 plant species were identified; gardens of African American households were rich in ornamental species, while those of Chinese-origin households had a depauperate flora. Shade trees and a developed shrub layer were absent from most gardens, suggesting a tradeoff in ecosystem services favoring food production. Only 9.6% of the inventoried species were native to the Chicago area.

Valerie Chiykowski, Guhan Chendurnathan, Jun S. Lee, Lius Daniel · cIRcle (University of British Columbia) · Canada

This project at the University of British Columbia's Student Union Building (SUB) aimed to reduce contamination in post-consumer organics bins using visual prompts. While the intervention successfully decreased both the percentage weight and level of contamination, the overall weight of compostable waste also decreased post-intervention. The study suggests considering confounding factors like a sustainability fair during baseline data collection and improved bins, and proposes an infrared sensor-based audio prompt system for future efforts.

Andrew Hursthouse, T. E. Leitão, Annette Voigt, Avigail Heller, Béatrice Bechet, Paulo Brito da Luz · HAL (Le Centre pour la Communication Scientifique Directe) · Europe

This chapter overviews factors influencing the chemical, physical, and biological status of soils, water, and the biosphere in urban allotment gardens. It highlights that urban garden soils, water, and biosphere are affected by pollution due to their location in city centers or suburbs, with traffic infrastructure and industrial zones widely identified as impacting soil and water quality. Concerns over long-term risks from pollutant transfer (mainly metals) from soil to plants in these uncontrolled environments have been widely publicized.

M.P Dr. Enny Zulaika · · Indonesia

A study using Azotobacter isolated from eco urban farming land at ITS, Indonesia, tested resistance and bioaccumulation of mercury (HgCl2) via selective media isolation, streak resistance testing and atomic absorption measurement, analyzed by ANOVA and LSD at the 5% level. Three isolates (A5, A6, A9) tolerated HgCl2 up to 20 mg/L, and at 5 mg/L exposure the highest bioaccumulation efficiency was recorded for A5 (89%) and A9 (87%).

Anjar Lulu Sakinah · · Indonesia

Mercury is a highly toxic and hazardous heavy metal, and bacteria able to live in mercury-contaminated habitats — mercury-resistant bacteria, including Azotobacter — are known to exist. This study aimed to obtain superior Azotobacter isolates resistant to mercuric chloride (HgCl2) from land at the ITS (Institut Teknologi Sepuluh Nopember) Eco Urban Farming site — land where mercury contamination was present — and to determine mercury reductase enzyme activity as a bioreductant converting Hg2+ to Hg0. Isolation used selective Azotobacter agar media, resistance was tested by a slant-agar streak method containing HgCl2, and mercury reductase activity was analyzed using the MRA method and spectrophotometry at 340 nm. Ten HgCl2-resistant Azotobacter isolates were obtained; isolates A5 and A9 tolerated 10 mg/L HgCl2 with optimal growth and relatively high mercury reductase activity, showing a reduction capacity of ≥3 mg/L and a reduction efficiency above 70% at an HgCl2 concentration of 5 mg/L.

M. G. Dahiru, Onaiwu Idahosa Enabulele · · Nigeria (Kano)

Microbiological and physicochemical parameters of urban wastewater from the Jakara Canal in Kano were analyzed to assess its potential for irrigation. Mean fecal coliform counts ranged from 64.43 ± 63.20 MPN 100/ml to 216.85 ± 350.16 MPN 100/ml, increasing along the canal. All physicochemical parameters were within FEPA and WHO/FAO acceptable limits, but conductivity needed monitoring to avoid salinity.

Rosangela Medeiros Hespanhol · Confins · Brazil (Natal)

This study analyzed the trajectory of farmers from AMIGS (Association of Friends and Producers of Vegetables Residents of Sitio Gramoré and Adjacencies), a significant vegetable supplier in Natal, Brazil, who have been transitioning from conventional to organic production since 2012. The organization of farmers through the association and partnerships with companies and institutions were crucial for enabling this change, reducing dependence on intermediaries through direct sales at ecological fairs. However, problems related to the individual acquisition of inputs and conflicts with farmers still using conventional systems were observed.

David Mkwambisi, Andrew J. Dougill, Philip Antwi‐Agyei, C. P. Chabvuta · CABI eBooks · Malawi

Research in Lilongwe and Blantyre, Malawi, assessed urban agriculture's potential to improve soil quality, crop yields, and livelihoods. Preliminary evidence showed urban waste could address food insecurity and soil nutrient benefits, but several constraints in waste management were identified. City authorities are not proactively utilizing organic municipal waste for soil quality and agricultural production benefits.

Klaus Lorenz · Soil Science · Global

Urban agriculture (UA) engages approximately 800 million people globally and covers over 67 million hectares of urban cropland. While UA contributes to food security, growing food in urban ecosystems, particularly on degraded urban soils, presents challenges. Past research on UA has focused on social sciences, and although studies on urban soils have increased, many urban areas remain neglected. Further research and dissemination of knowledge are needed on how to maintain or enhance urban soil fertility through soil and land-use management practices.

José Tobias Marks Machado, Jeferson Tonin, Evandro Pedro Schneider · SHILAP Revista de lepidopterología · Brazil

This study, conducted in two schools in Cerro Largo - RS, Brazil, during 2013, performed a post-implementation analysis of ecologically based school gardens introduced through a university extension program. Positive results included the proliferation of similar projects. However, significant difficulties were emphasized in integrating the school gardens with disciplinary education, attributed to existing conservatism in the educational context.

J.S.C. Wiskerke · · Global

This chapter focuses on urban food supplies and the challenges of managing waste flows from urban households and markets in developing countries. Large amounts of municipal solid waste, human excreta, and wastewater are produced, most of which end up in non-engineered landfills or pollute the urban environment. It is noted that these wastes pollute the urban environment, especially in low-income countries with less developed sanitation infrastructure.

Vide Adedayo · Journal of Research in National Development · Nigeria (Lagos)

This study investigated poultry waste management in urban vegetable farms in Metropolitan Lagos from an ecosystem to human health perspective. Using a transdisciplinary approach, community participation, and socio-cultural, physiochemical, microbiological, and clinical information, the research revealed negative impacts and health problems associated with poultry waste management due to poor storage, composting, and packaging techniques. Consequently, adverse effects on users were identified.

Geneviève S. Metson, Elena M. Bennett · PLoS ONE · Canada (Montreal)

This study quantified the role of urban agriculture (UA) in phosphorus (P) cycling in Montreal, Canada, using existing data and surveys of local UA practitioners. In 2012, Montreal imported 3.5 Gg of P in food, with 2.63 Gg accumulating in landfills, 0.36 Gg discharged to local waters, and only 0.09 Gg recycled through composting. UA was found to be only a small sub-system in the city's overall P cycle, contributing just 0.44% of the P consumed as food. Although recycling rates within the UA system are high, the land area dedicated to UA is too small to accommodate all P waste produced on the island.

B.M. Mercado-Borrayo, Silke Cram Heydrich, Irma Rosas‐Pérez, Manuel Hernández Quiroz, Claudia Ponce De León Hill · International Journal of Phytoremediation · Mexico

In a natural wetland in the Mexico City Metropolitan Area — a major supplier of crops and flowers whose canals hold high concentrations of organochlorine (OC) and organophosphorus (OP) pesticides — bioaccumulation of these pesticides was studied in water hyacinth (Eichhornia crassipes), a plant considered a plague but suggested in the literature to have phytoremediation potential. In vivo bioaccumulation differences for OC pesticides were largely explained by their log Kow, while all OP pesticides showed bioaccumulation regardless of log Kow, and the higher bioaccumulation factors of some accumulated OC pesticides could not be explained by log Kow alone, suggesting passive transport into the plant. Translocation ratios showed water hyacinth to be an accumulating plant with phytoremediation potential for all the organophosphorus pesticides studied and some organochlorine pesticides, and an equation for free water surface wetlands with floating macrophytes showed pesticide removal by the wetland with room for improvement through better management.

Ricardo da Silva Claudio, Souto de Sousa J uacute nior Francisco, Ismael de Souza Francisco, da Silva Dias Nildo, Nogueira de Sousa Neto Osvaldo, Cruz Portela Jeane, Cl aacute udia Medeiros Souza Ana, Christina Nascimento Porto Vania · African Journal of Agricultural Research · Brazil

A participatory action-research project in a community garden in Bom Jesus, Campo Grande, Rio Grande do Norte, Brazil, tested irrigating organic vegetables (coriander, chive, tomato, rocket) with reject brine from a water desalination/treatment station. All species irrigated with the saline waste water showed yield losses of 25.30% to 26.7% compared with conventional fresh-water irrigation, though some biomass was still produced, and the project changed residents' views on disposing of and reusing the saline waste.

Nimoh Fred, Ohene-Yankyera Kwasi, Poku Kofi, Konradsen Flemming, Claude-François Robert · Journal of Development and Agricultural Economics · Ghana

A study in Ghana's Shai-Osudoku district investigated farmers' attitudes toward excreta reuse for peri-urban agriculture, surveying 400 randomly selected respondents. A majority of respondents disagreed that excreta are waste and were willing to use them as fertilizer. However, a majority also agreed that excreta can pose health risks, and perceptions on reuse differed among households.

Yuki Sampei, Yuji Hara, Akinobu Murakami, Armand PALIJON, Kazuaki Tsuchiya, Makoto Yokohari · Journal of The Japanese Institute of Landscape Architecture · Philippines (Metro Manila)

The nitrogen supply-demand balance in compost and vegetable production on vacant lots in suburban residential districts of Quezon City, Metro Manila, was assessed. Analysis revealed that almost half of the subdivisions faced nitrogen oversupply, while several were in short supply. Current centralized composting facilities may not adequately support a continuous compost recycling system due to their distribution patterns. It was proposed that existing barangay-based policies on organic waste management and urban agriculture require greater flexibility and attention to coordination systems across subdivision boundaries.

Anjar Lulu Sakinah, Enny Zulaika · Jurnal Sains dan Seni ITS · Indonesia

This study aimed to isolate Azotobacter strains from the Eco Urban Farming ITS land in Indonesia that are resistant to HgCl2 and potentially produce mercury reductase enzymes. Ten HgCl2-resistant Azotobacter isolates were obtained, with isolates A5, A6, and A9 showing the highest resistance at 20 mg/L HgCl2. Isolates A5 and A9 were identified as having the potential to produce mercury reductase enzymes.

Yuki Sampei, Yuji Hara, Akinobu Murakami, Armando M. Palijon, Kazuaki Tsuchiya, Makoto Yokohari · Institutional Repositories DataBase (IRDB) · Philippines

This study assessed the nitrogen supply-demand balance in compost and vegetable production on vacant lots in subdivisions and barangays in Quezon City, Metro Manila, using GIS. It found that nearly half of the subdivisions experienced nitrogen oversupply, while others faced shortages. Although cooperation among subdivisions within a barangay could improve nitrogen balance, the current centralized composting facilities were deemed insufficient to support a continuous compost recycling system due to their distribution patterns. The study concluded that current barangay-based policies on organic waste management and urban agriculture need greater flexibility and attention to inter-subdivision coordination across barangay boundaries.

Maxine J. Levin · Soil Horizons · United States

This commentary highlights a growing demand for soil information for green economy initiatives and climate change adaptation over the last 25 years. Despite this, USDA's funding and technical support for soil surveys in urban and nonfarm areas have been inconsistent and, in some places, nonexistent. The author argues for the vital role of modern soil surveys in addressing current needs.

Shogo Mlozi · International NGO Journal · Tanzania

This paper assesses the knowledge of livestock keepers in Dar es Salaam, Tanzania, regarding the climate change effects of their activities. Over two-thirds of respondents did not believe solid waste, liquid waste, and pollution from livestock would affect future climate risks. However, they did perceive chemical pollution and land degradation from urban and peri-urban agriculture (UPA) livestock keeping as having climate change effects.

Aubin Ondo, Pascale Prudent, C. Massiani, Menye Biyogo, Mariane Domeizel, Jacques Rabier, François Eba · Journal of the Serbian Chemical Society · Gabon (Libreville)

An assessment of urban agriculture's impact on soil properties and metal uptake by leafy vegetables in Libreville, Gabon, found strong soil acidification and decreased nutrient/metal concentrations due to agricultural practices. Metal transfer to plants was significant, with amaranth accumulating more metals than other vegetables, though cadmium and lead were not detectable in plant tissues. Amaranth and roselle preferentially concentrated metals in their leaves.

Evaristo Mwaba Kapungwe · Indonesian Journal of Biotechnology (Universitas Gadjah Mada) · Zambia

This study investigated farming practices related to heavy metal contaminated wastewater irrigated farming in two peri-urban areas of Zambia: New Farm in Mufulira and Chilumba Gardens in Kafue. Data was collected by observing crop cultivation activities at field plots along transects in stratified land zones. The results revealed that farming practices were characterized by traditional land management and multiple cropping systems, influenced by agro-ecological factors and the availability of heavy metal contaminated wastewater, which has the potential to contaminate soils and crops.

Jennifer E. Reeves · OhioLink ETD Center (Ohio Library and Information Network) · United States (Cleveland, Ohio)

This two-year study in Cleveland, Ohio, USA, investigated urban soil health via nematode food web analysis and crop productivity via tomato fruit yield in urban gardens. Market gardens showed significantly more soil organic matter, nitrogen pools, and nematode presence than community gardens in both 2011 and 2012. However, despite these differences, there was no significant difference in the total yield of tomatoes per square meter between market and community garden types in either year. Gardens with raised beds had significantly more soil moisture content and soil organic matter than those with flat beds.

Josh Beniston · The Knowledge Bank (The Ohio State University) · United States (Ohio)

An experiment on assessing and managing soil quality for urban agriculture was conducted during the 2011 and 2012 growing seasons on demolished vacant urban lots in Youngstown, Ohio. Soil compaction was identified as a primary constraint, with high bulk density values of 1.79 g cm⁻³ for in-ground plots and 1.55 g cm⁻³ for raised beds. Crop yield data from 2011 showed that both compost-amended and compost + biochar-amended plots had significantly greater crop yields than control plots, with compost + biochar plots achieving the highest harvest index values.