Research & reports

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.

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.

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.

Sarah Legg · Figshare · United States (Wyoming)

ACRES Student Farm, a University of Wyoming organization, has grown significantly over six years, providing local produce, CSA shares, composting, and educational opportunities. However, the farm suffers from continuous losses in efficiency and acquired knowledge due to the transient nature of its student management and workforce, leading to unsustainable internal functioning. This project aims to develop a management plan and handbook to address these issues and improve the farm's operational efficiency.

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.

Jenny Calabio, Ma. Luisa Albacete · WVSU Research Journal · Philippines (Iloilo City)

This study, conducted from July 2007 to July 2008 at the Urban Agriculture Demonstration Site in La Paz, Iloilo City, evaluated soil media and ameliorants for container-grown green onion, pechay, and tomato. Pure compost was found to be the best medium for increasing yields. However, the use of IMO and rice hull as soil ameliorants did not increase yields for the three tested vegetables, and rice hull generally reduced pechay yields.

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.

Mirelys Rodríguez Alfaro, Olegário Muñiz Ugarte, Bernardo Calero Martín, A. Álvarez, Francisco Martínez Rodríguez, Teudys Limeres Jiménez, Mercedes Orphee Montoya, Adriana M. de Aguilar Accioly · DOAJ (DOAJ: Directory of Open Access Journals) · Cuba

This study evaluated the heavy metal content of Cadmium, Lead, and Nickel in organic fertilizers (composts from urban solid waste) and substrates, and their effect on vegetables grown in organoponics in Havana and Guantánamo, Cuba. Composts obtained from unsorted urban solid waste and the substrates prepared from them were found to contain heavy metals, especially Cadmium and Lead, above maximum permissible limits. It was concluded that these products should not be used for food production, as these metals translocate to the edible parts of the cultivated vegetables.

Sally Brown, Ingrid Clausen, Mark A. Chappell, Kirk G. Scheckel, M. Newville, Ganga M. Hettiarachchi · Journal of Environmental Quality · Global

Against a background in which the safety of urban farming has been questioned because of possible contamination in urban soils, this study tested whether high-iron biosolids-based composts could reduce the bioaccessibility of soil lead (Pb) and arsenic (As), using two laboratory incubations and a field trial. Pb and As bioaccessibility were assessed with an in vitro assay, and changes in Pb, As, and Fe speciation were analyzed on select samples using micro-X-ray fluorescence mapping and micro-XANES. A compost with iron added to wastewater-treatment residuals (Fe WTR compost), applied to soil at 100 g/kg, decreased Pb bioaccessibility in both laboratory incubations, though results for As were mixed. In contrast, the composts tested in the field trial (with iron added as Fe powder or FeCl) did not reduce bioaccessible Pb and showed only limited reductions in bioaccessible As; these same composts also had no effect on Pb bioaccessibility in the second laboratory incubation. The study concludes that high-iron biosolids compost is effective at reducing Pb accessibility only for certain types of iron-rich materials.

Michael Raleigh · eCommons (Cornell University) · United States (Buffalo)

The City of Buffalo has made progress in accepting urban farming on vacant land, but remains unwilling to take risks in this area. Policies restrict farmers' access to land, long-term security, food diversity (including animals), and sales. To foster urban farming, the City should amend these policies to grant farmers more freedom and could promote farming through a city-wide composting program and a demolition policy requiring vacant lots to be seeded with clover.

Julian S. Yates, Jutta Gutberlet · Environment and Planning A Economy and Space · Brazil (Diadema)

This paper analyzes food waste flows in Diadema, Brazil, through an urban political ecology lens, focusing on integrated organic waste management for composting and urban food production. While presented as a means for positive socioecological change, the process is characterized by conflict and potential exploitation. Broader structural conditions also constrain the system's ability to offer an alternative to existing waste-management models.

Hygin Faust Kakai, Alban Gilles Kakai, Armelle Grey Tohouegnon · VertigO · Benin (Cotonou)

This study in Benin examined urban agriculture and waste valorization in Cotonou, Abomey, and Abomey-Calavi. In Cotonou, overexploitation of sandy, organic-poor soil in market gardening led to soil impoverishment, forcing gardeners to use chemical fertilizers with negative environmental impacts. However, some market gardeners adopted compost use, transitioning to organized organic urban agriculture after a waste management project supported waste valorization. This dynamic was not observed in Abomey, where urban agriculture is practiced in family spaces and public areas, unlike Cotonou's developed sites. Abomey-Calavi, despite rapid demographic growth, was almost devoid of urban agriculture practices.

O. Muñiz, M. Ternero, Álvarez Montero, F. Martínez, T. Limeres, O. Jouber, M. Orphee, Julia Vidan Estevez, B. Calero, F. A. de Alcantara, Adriana María de Aguiar Accioly · Portuguese National Funding Agency for Science, Research and Technology (RCAAP Project by FCT) · Global

This paper situates its topic within the urban agriculture movement, which it describes as having successfully enabled low-input food production in cities, noting that organoponicos — plots focused on producing leafy vegetables and condiment crops in organic substrates — have driven up demand for organic material sources. The title indicates the study addresses the effect of using heavy-metal-contaminated compost on vegetable production, but the available abstract provides only this background context, with no results on contamination or crop impact stated.

J.N. Hogard, Julius N. Fobil, Godfred K. Ofosu-Budu, D. Carboo, Nii‐Ayi Ankrah, Alexander K. Nyarko · · Ghana

This study in Ghana investigated the macro-nutrient content and heavy metal concentrations in solid waste composts to assess their potential for soil fertility amelioration and health implications in urban and peri-urban agriculture. Overall NPK concentration was low, with agricultural waste composts showing higher total N, K, and organic carbon than municipal solid waste (MSW) composts. Heavy metal concentrations for Ni, Zn, Cu, and Cd were generally low and within Australian standards. However, lead (Pb) concentration in mixed MSW composts was significantly high during the dry season, exceeding the Australian limit of 150 mg/kg Pb for unrestricted use. Seasons and composting processes were found to be important determinants of toxic metal concentrations in final compost products.

Erin Foster West · · United States (Minneapolis)

This study explores the interaction between community gardens and public agencies in Minneapolis and Hennepin County, United States. It identifies that despite a large number of community gardens in the Twin Cities Metro Area, there is no comprehensive city policy for community gardening, making land acquisition difficult as vacant land becomes scarce. The research inventories public policies related to land use, water, and compost specific to community gardens, highlighting the need for public agencies to provide essential services.

E. Mensah, Philip Amoah, Pay Drechsel, Robert Clement Abaidoo · CABI Publishing eBooks · Sub-Saharan Africa

This work, presented as case studies from Accra and Kumasi, addresses environmental concerns of urban and peri-urban agriculture. It focuses on waste composting for urban and peri-urban agriculture, aiming to close the rural-urban nutrient cycle in Sub-Saharan Africa.

Lee M · PubMed · Ethiopia

In Ethiopia, urban agriculture faces significant challenges due to government disapproval of public land use for farming and difficulty in obtaining credit. A 1983 survey in Addis Ababa found that 17% of 1352 households produced their own food on less than 25 sq. meters, with 90% of non-farmers citing lack of land. Despite urban agricultural cooperatives demonstrating 70% higher member income, their lack of government legalization prevents access to loans for productivity improvement.