Research & reports

Xiaona Li · Nongye huanjing kexue xuebao · China

A study measuring dioxin-like compound (PCDD/Fs) concentrations in 23 surface soil samples collected from different areas of Baiyin City, China, using HRGC/HRMS (high-resolution gas chromatography/high-resolution mass spectrometry). The concentration range of 2,3,7,8-PCDD/Fs was 0.42-8.56 pg I-TEQ/g, averaging 2.28 pg I-TEQ/g. By land-use type, concentrations averaged 3.37 pg I-TEQ/g in industrial areas, 1.31 in urban areas, 1.01 in agricultural areas, and 0.85 in background areas, following the order industrial > urban > agricultural > background. Higher-chlorinated isomers were the dominant contributors to total toxic equivalency (TEQ) in most samples.

Mamadou Ndiaye, S. Niang, H.‐R. Pfeifer, Raffaele Peduzzi, Mauro Tonolla, Y Dieng · Irrigation and Drainage · Senegal

Lettuces grown at two urban agricultural sites (Pikine and Patte d'Oie) near Dakar, Senegal, and sold in local markets were tested for microbial contamination linked to irrigation water. Salmonella spp. positivity was 6% at Pikine and 7% at Patte d'Oie farm sites, with lettuces irrigated by shallow 'Ceanes' groundwater most contaminated at both sites (8%), compared to wastewater irrigation (4% at Pikine) and well water (5% at Patte d'Oie); at market, Salmonella was isolated at every marketplace surveyed, with higher rates around Patte d'Oie (9% at Grand Yoff, 11% at Dalifort) than around Pikine (4% at Zinc, 2% at Sham) or the control site Rufisque (2%), and lettuces washed with Ceanes water before sale were more contaminated than those rinsed with tap water. Reusing wastewater for irrigation is presented as an alternative to animal manure, with the microbial contamination risk significantly reducible by washing vegetables with tap water before sale.

G. M. Hettiarachchi, Sabine Martin, A. David Rae, Phillip P. Defoe, Dennis Presely, G. M. Pierzysnki · · United States

Using a newly established urban community garden in Kansas City as a case example, this study examines the challenges of converting brownfield sites — abandoned or underutilized properties where environmental concerns impede redevelopment — into community gardens. Soil at the site was found to contain mildly elevated levels of lead (Pb) and detectable levels of DDT/DDE (an organochlorine pesticide). Based on an evaluation of soil properties, safety and corrective measures were proposed and implemented to reduce both direct (soil-to-human) and indirect (soil-to-plant-to-human) exposure for gardeners and their children, and field test plots with three crop types showing different contaminant-uptake patterns were established to evaluate site-specific soil amendments for reducing lead bioavailability.

Nicola Silvestri, E. Bonari · CINECA IRIS Institutial research information system (University of Pisa) · Italy

Focusing on the area around Lake Massaciuccoli in Tuscany, Italy, this paper discusses the relationship between the management of peri-urban agricultural land — the transition zone between city and countryside — and the lake's eutrophication problem. It argues that proper management of the extensive agricultural areas within this heavily anthropized territory could contribute significantly to resolving the lake's eutrophication through management and structural interventions, while noting that partially reorganizing existing agricultural models carries both cost and difficulty.

Mark Matsa, Thomas Marambanyika · Journal of Environmental Extension · Africa

A study assessing concentration levels of lead (Pb), cadmium (Cd) and sulphides (SO2) within and around Gweru's sole official waste dumpsite in Zimbabwe. Harsh economic conditions in the city have driven further expansion of urban agriculture on open spaces, with residents growing staple food crops such as maize and sweet potatoes for subsistence on numerous plots surrounding the dumpsite; the study states that ingesting crops grown near the dumpsite is likely to put residents' lives at risk. Soil sampling points along transects on and around the dumpsite were randomly selected using ArcView GIS, with sulphide concentrations measured by Leco machine and lead and cadmium by atomic absorption spectrometer. Independent t-test results showed the concentration levels of the three pollutants were significantly elevated from one sampling point to the next, within and around the dumpsite.

Zhigang Wei · Journal of Qingdao Agricultural University · China

A comprehensive survey of agricultural structure and layout in Qingdao, China. It states the sector has achieved transformation and upgrading, with growing agricultural industrialization and increasingly optimized layout of agricultural areas approaching cluster-scale planting and breeding industries. However, it reports that further adjustment of planting structure faces major bottlenecks due to limits on arable land and food security: the traditional small-scale fish-farming model seriously restricts further development of animal husbandry and aquaculture, and fluctuating agricultural product markets combined with a lack of competitiveness are affecting the agricultural industry's layout. It concludes that crop structure needs further adjustment, that production should be scaled up, specialized and standardized, and that urban agriculture should be emphasized to expand agricultural functions.

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.

Chandra Sen · Journal of Interdisciplinary Economics · India

This study estimated the impact of air pollution on crop yields in peri-urban areas of Varanasi, India. Phytotoxic gases are known to cause major yield reductions in important crops in developing countries, and in this study all major crops grown in peri-urban Varanasi — paddy, pigeon pea, maize, wheat, and potato — showed yield reductions attributable to air pollution. Air pollution was found to reduce both the yield and the nutritional quality of the produce, and the study calls for similar validation studies in other cities and for efforts to reduce air pollution in the city to improve crop yield and quality.

Adam Shiloh Moates · Culture & Agriculture · Colombia

A case study of clasificadores (urban waste sorters) in Montevideo, Uruguay, focusing on the subset known as clasificadores criadores de cerdos (CCdCs) who raise hogs alongside recycling. CCdCs do not fit the standard urban agriculture model since they do not garden but instead feed collected organic refuse to hogs. Raising hogs in the irregular settlements where CCdCs live is illegal, and very little of the hog meat they produce is consumed by the CCdCs themselves; out-of-town hog farmers transport their "bootleg," trash-fed hogs to legitimate markets to close the legal loop for what remains a clandestine production system. Although clasificadores have recently organized cooperatives and a labor union, the hog-raising activity itself remains illegal and dependent on this informal, off-book market channel.

Cantor, Kelly-M · LA Referencia (Red Federada de Repositorios Institucionales de Publicaciones Científicas) · Colombia (Bogotá)

This study analyzed urban agriculture practiced by forcibly displaced residents and by vulnerable populations living in poverty in southern Bogotá and the Soacha locality, Colombia, using a livelihoods approach and drawing on 20 local actors and public/private institutions that had run urban agriculture programs as its information source. It found that urban agriculture carries symbolic value as a livelihood and occupational alternative, framed around collective wellbeing beyond monetary value, and reflects a struggle by peasant identity to survive within city life—but concluded that it is not an integrally sustainable activity.

Cezary Kabała, T. Chodak, L. Szerszeń, Anna Karczewska, Katarzyna Szopka, Urszula Fratczak · Fresenius environmental bulletin · Poland (Wroclaw)

An analysis of 180 allotment garden soils in Wroclaw, Poland, found that concentrations of Cu, Pb, and Zn (12.5-659 mg Pb kg-1, 38.1-2103 mg Zn kg-1, 12.9-595 mg Cu kg-1) were influenced by industrial pollution sources, organic matter, pH, and macronutrients. Soils in gardens on former housing or industrial areas had significantly higher metal concentrations. Up to 35% of soils in the city zone were excessively contaminated, making them unsuitable for vegetable and fruit production and requiring reclamation.

M.R. Gorham, Tina M. Waliczek, Amy Snelgrove, Jayne M. Zajicek · HortTechnology · United States (Houston)

A pilot study in Houston, Texas, investigated the impact of 11 established community gardens on property crime numbers using 2005 crime data. Statistical comparisons between community garden areas and randomly selected city areas showed no statistically significant differences in the mean number of crime occurrences. The presence of a community garden was not found to be a predictor of a lower crime rate for a neighborhood.

Emma Schroeder, Julie Schneider · · United States (Eagle Heights)

Julie Schneider's 2009 interview discusses her five years at the Eagle Heights Community Garden. She described vegetables grown, organic gardening, rules and restrictions, and tensions with the university, as well as changes in the community gardens since the early 1990s. This interview was conducted for a Master's thesis on the Eagle Heights Community Gardens.

W.-L. Rao, Z.-K. Zhang, Runzhong Li · Plant Disease · China (Kunming)

In June 2007, sweet cherry trees with mottling and mosaic symptoms were observed in a private garden near Kunming, Yunnan Province, China. Twenty-four samples from sweet cherry, sour cherry, flowering cherry, and peach trees in private and community gardens were tested for eight viruses by RT-PCR. Cherry virus A (CVA) was detected in two symptomatic sweet cherry trees, marking the first report of CVA in sweet cherry in China.

Wendy Heiger‐Bernays, Alexa Fraser, Vaughn R. Burns, Kerry Diskin, David Pierotti, K Merchant-Borna, Michael D. McClean, Daniel J. Brabander, H. Patricia Hynes · PubMed · United States

A study characterized urban community garden soils contaminated by timbers, specifically finding elevated levels of polycyclic aromatic hydrocarbons (PAHs) from railroad ties and arsenic from chromated copper arsenate (CCA) treated lumber. Researchers determined the extent of contamination, designed a remediation plan, and assessed the safety of adding city compost as a soil amendment in Boston community gardens. Recommendations for healthful gardening practices were also provided.

Alec Thornton · Development in Practice · Fiji

This article examines the impact of Fiji's squatter-resettlement scheme on the livelihoods of 'farming squatters' engaged in urban agriculture. Interviews with key informants and squatter residents revealed contrasting attitudes and approaches, indicating that the scheme threatens these livelihoods. The article suggests a more participatory process to address the needs of 'farming squatters'.

W. Van Averbeke · Water SA · South Africa (Pretoria)

This study in five informal settlements of Atteridgeville, Pretoria, South Africa, used a pilot study, household survey, and multiple case studies to assess urban farming's contribution to food security and household income. While over half of households participated in urban farming, its contribution to total household income and food security was generally modest. Main constraints included lack of space and limited access to irrigation water.

Pay Drechsel, Liqa Raschid-Sally, Robert Clement Abaidoo · · Ghana (Accra)

Urbanization in West Africa has led to most domestic wastewater contaminating surface water sources. In Accra, Ghana, vegetables on urban markets are highly contaminated, with about 200,000 urban dwellers consuming street food containing raw vegetables from these sources daily. This research explores on-farm risk mitigation options, finding potential to significantly reduce helminth egg counts and bacterial contamination through improved washing practices.

Karin Ahrné, Jan Bengtsson, Thomas Elmqvist · PLoS ONE · Sweden (Stockholm)

This study investigated bumble bees in allotment gardens along an urbanization gradient from inner Stockholm to rural areas. Findings showed that bumble bee diversity decreased with increasing urbanization, from approximately eight species in rural areas to five to six species in urban allotment gardens. Higher variability in the abundance of certain species in the most urban areas suggested a potentially weaker reliability of the pollination ecosystem service in areas strongly influenced by human activity.

Mattia Celio, Christopher A. Scott, Mark Giordano · Geographical Journal · India (Hyderabad)

A study in Hyderabad, India, examined urban water capture and its impacts on pre-existing claims, particularly agriculture. Urban water appropriation often leads to conflict with existing water uses. The findings indicate that the magnitude and direction of impacts from urban water transfer on agriculture vary spatially and temporally, depending on location-specific rainfall patterns, existing water infrastructure and institutions, and farmers' adaptive capacities, including recourse to groundwater.

Liang Wei · Anhui nongye kexue · China (Dingxi)

This study analyzed the advantages, disadvantages, and existing problems in the development of urban agriculture in Dingxi City, China. Strategic concepts and countermeasures were proposed to provide consultation for urban agriculture development in Dingxi City and similar regions.

Remi Adeyemo, F. Kuhlmann · Tropicultura · Nigeria

This paper evaluates the efficiency of resource use in urban food crop production in five districts of two cities in southwestern Nigeria, based on an effective sample of 120 respondents. The analysis showed that urban food crop production is profitable, with an average revenue of N51,294 per hectare and a gross margin of N23,688. However, there was disequilibrium in resource use, with planting seeds and agrochemicals used efficiently, but land and labor used inefficiently, indicating that urban food crop production has not yet attained an optimum level of resource combination.

Rodrigue V.C. Diogo, Andreas Buerkert, Eva Schlecht · Nutrient Cycling in Agroecosystems · Niger (Niamey)

This 24-month study investigated nutrient efficiency and food safety in urban and peri-urban agriculture in Niamey, Niger. Nutrient inputs and offtakes were quantified for 10 vegetable gardens and 9 millet fields, and contamination of irrigation water and selected vegetables with fecal pathogens and heavy metals was determined. Above-threshold levels of Salmonella spp. and Escherichia coli were detected in lettuce irrigated with river water and fertilized with animal manure, and in lettuce irrigated with wastewater, indicating food safety concerns.

Clara Irazábal, Anita Punja · Journal of Urban Affairs · United States (Los Angeles)

This qualitative case study analyzes the destruction of the 14-acre South Central Farm in Los Angeles in July 2006, arguing it was a landscape of resistance against discriminatory legal and planning practices. The study contends that environmental justice and planning ethics provided a substantive rationale for the city to prevent its dismantling. This case highlights a failure in governance to protect community gardens threatened by dismantlement in capitalist societies.

Mark Redwood · Open House International · Global

Urban farmers often produce food on land with limited or no security of tenure, exposing them to the risk of being evicted for more profitable land uses. Without legal status, most forms of credit are inaccessible to farmers, pushing them to the margins. Recent projects suggest that banking systems need to develop a methodology to value informally controlled lands and indicate that advocacy groups can increase security and access to land for urban farmers.