Tous les articles par Eric Duchemin

Urban versus conventional agriculture, taxonomy of resource profiles: a review

Urban agriculture appears to be a means to combat the environmental pressure of increasing urbanization and food demand. However, there is hitherto limited knowledge of the efficiency and scaling up of practices of urban farming. Here, we review the claims on urban agriculture’s comparative performance relative to conventional food production. Our main findings are as follows: (1) benefits, such as reduced embodied greenhouse gases, urban heat island reduction, and storm water mitigation, have strong support in current literature. (2) Other benefits such as food waste minimization and ecological footprint reduction require further exploration. (3) Urban agriculture benefits to both food supply chains and urban ecosystems vary considerably with system type. To facilitate the comparison of urban agriculture systems we propose a classification based on (1) conditioning of the growing space and (2) the level of integration with buildings. Lastly, we compare the predicted environmental performance of the four main types of urban agriculture that arise through the application of the taxonomy. The findings show how taxonomy can aid future research on the intersection of urban food production and the larger material and energy regimes of cities (the “urban metabolism”).

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L’aventure agricole montréalaise : une géopolitique urbaine quid de tensions? – Archipel

Depuis plusieurs années, la question du système alimentaire prend de l'ampleur à Montréal. De nombreuses initiatives en agriculture urbaine (AU) prennent racine dans la métropole par une réappropriation citoyenne de l'espace public. Elles prennent la forme de jardins communautaires et collectifs, ou bien pour innover vers d'autres formes de production alimentaire en milieu urbain (toits verts, jardins à partager, etc.), mais sans toutefois réussir à se pérenniser dans l'espace et le temps. Dans ce contexte, ce mémoire analyse la dimension géopolitique de la production alimentaire présente sur le territoire montréalais. Il aspire à mettre en lumière les raisons, les acteurs et les effets sur la ville de Montréal, spécifiquement sur l'arrondissement du Plateau-Mont-Royal, et d'analyser les interactions externes et internes entre les différents acteurs de l'AU, ainsi que les représentations et dynamiques territoriales qui les accompagnent et les soutiennent. Elle vise donc à mettre en évidence les interactions des acteurs locaux, régionaux et nationaux pour voir dans quelle mesure la question de l'AU est un objet de tensions entre les acteurs par l'interprétation de leurs représentations sociales et territoriales. L'originalité de ce travail réside dans le fait qu'il constitue la première tentative à l'étude d'une géopolitique locale de l'AU. Ce mémoire s'attache à démontrer la pertinence géographique dans son cadre d'analyse et méthodologique. L'analyse fait preuve ici de sa capacité à être opérationnalisé dans une recherche priorisant la méthode géopolitique. Les résultats obtenus permettent d'élargir les connaissances sur la question des potentialités, des acteurs et des représentations de l'AU sur le territoire montréalais et d'ouvrir de nouvelles perspectives sur la matière. La viabilité de l'AU est fonction de la prise en compte des spécificités du territoire, des politiques municipales, des représentations socio-territoriales des différents acteurs, des potentialités et des interactions entre les fonctions économiques, sociales et environnementales d'un territoire urbain. Malgré une forte volonté citoyenne pour l'implantation de projets en AU sur le territoire montréalais, leur viabilité en est toutefois diminuée sans un soutien politique, par l'intermédiaire de politiques municipales, de programmes de subvention à court et long terme, et d'une accessibilité à des espaces cultivables peu dispendieux. Avec l'appui du politique, les projets en AU augmentent leur probabilité à être pérenniser dans l'espace et le temps

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Growing fresh fruits and vegetables in an urban landscape: A geospatial assessment of ground level and rooftop urban agriculture potential in Boston, USA – ScienceDirect

Urban parcels can potentially be leveraged for developing a local urban food system by growing high yield food crops. Here, a remote sensing and GIS-based modeling framework was developed to locate and quantify available area for urban farming, including both rooftop and ground level areas in the city of Boston, MA, USA. Geoprocessing and spatial analysis tools were used to process geographic data layers for zoning, ownership, slope, soil quality, and adequate light availability. Surface slope (roof pitch) was determined for all buildings in the city through the creation of a digital surface map from remotely sensed LiDAR data. Potential parcels from ground level public and private vacant lots and underutilized residential and commercial areas were mapped using publicly available datasets. Approximately 922 ha of rooftop and 1,250 ha of ground level parcels have been identified, representing 7.4% and 10% of the total land area in Boston, respectively. Finally, food yield values for common urban agricultural crops were used to estimate the city’s food production potential from the identified parcels. Despite Boston’s density, the mapped areas have potential to produce enough fresh fruits and vegetables for Boston’s population, while providing both environmental and economic co-benefits. The study outcome was compared with mapping and inventory results from other North American cities.

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Gardening as a mental health intervention: a review

The number of gardening-based mental health interventions is increasing, yet when the literature was last reviewed in 2003, limited evidence of their effectiveness was identified. The purpose of this paper is to evaluate the current evidence-base for gardening-based mental health interventions and projects through examining their reported benefits and the quality of research in this field.

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Characteristics and motivations of potential users of urban allotment gardens: The case of Vila Nova de Gaia municipal network of urban allotment gardens

Demand for urban allotment plots has recently increased in Portugal but little is known about the characteristics and motivations of the demanding population, and if and how its characteristics affect its motivations. In this article, we use the Municipal Network of Urban Allotment Gardens (MNUAG)1 launched by the Portuguese municipality of Vila Nova de Gaia for an exploratory Case Study research. Based on the data collected in the MNUAG application forms submitted in the period 2012–2013, we describe the characteristics and the motivations of the population demanding for urban allotment gardens (UAG)2 and run a logit model to find if and how the motivations are influenced by the characteristics. The population of applicants to the MNUAG is quite diverse. It has a balanced gender distribution and an average age of 47 years. Most of the applicants are between 25 and 64 years old, and belong to households with 2–4 members. To supplement family budget, occupation of leisure times, and access to organic farming are its most important motivations, followed by environmental concerns, the practice of physical exercise, and education. Motivations are influenced by the characteristics. This study has identified two groups of applicants with contrasting motivations. Food security is the only significant motivation for the unemployed and low-income applicants. Food safety, health concerns, environmental concerns, recreation, and education are common and frequent motivations among the upper and intermediate professional groups. Results can have future implications on the MNUAG, namely on the UAG location and typology, plot number, and plot size. To meet the demand of all the types of applicants, while fostering social cohesion, the municipality should reinforce its current small UAG structure and add to the MNUAG one or two productive parks.

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Viabilité des microfermes maraîchères biologiques : Une étude inductive combinant méthodes qualitatives et modélisation

L'agriculture urbaine est devenue en moins de vingt ans un sujet d'actualité politique et scientifique. La dimension multifonctionnelle de cette agriculture (souveraineté alimentaire urbaine, contribution au lien social, fourniture de services écosystémiques) est, plus qu'ailleurs, essentielle. Les modèles agricoles orthodoxes s'incorporent imparfaitement à ce cadre et, surtout, prennent difficilement place dans des espaces où la contrainte foncière est très forte. Les solutions à mettre en oeuvre sont donc à chercher en dehors de cette orthodoxie. La permaculture, cadre d'action de fermes déjà existantes, représente une alternative innovante et prometteuse, mais les systèmes et les pratiques qui s'y inscrivent demeurent très mal connus. Ce projet s'intéresse à ces systèmes, en s'appuyant sur une approche de modélisation qui permette de dépasser l'obstacle du faible nombre de situations observables. Il sera conduit en collaboration directe avec les agriculteurs innovateurs, dans une posture revendiquée de recherche-action. L'ambition est de construire un modèle conceptuel formalisé mathématiquement, dont l'exploration aboutisse à un ensemble de « métarègles » pour la définition et la conduite des systèmes maraichers éco-intensifs appropriés au contexte urbain, permettant aussi bien à des scientifiques qu'aux acteurs de terrain de répondre à la question « comment concevoir des règles dans le contexte donné » plutôt qu'à la question « quelles règles appliquer ». Abtract Urban agriculture became in less than twenty years a political and scientific current topic. The multifunctional dimension of this agriculture (urban food sovereignty, contribution to the social link, supply of ecosystem services) is, more than elsewhere, essential. The orthodox agricultural models fit imperfectly this framework and are hardly applied in spaces where the land constraint is very strong. The solutions to be implemented are thus to seek apart from this orthodoxy. Permaculture is the action frame of already existing farms, represents an innovative and promising alternative, but their systems and practices remain badly known. This PhD project is focused on such systems, by leaning on a modeling approach of their ecological and economic viability which allows overtaking the obstacle of the low number of observable situations. It will be led in direct collaboration with innovating farmers, in an asserted posture of research -action. The ambition is to build a mathematically formalized conceptual model, whose exploration leads to a set of meta-rules for the definition and the management of market-gardening systems appropriate to an urban context, allowing as well scientists as practitioners and policy-makers to answer the question "how to design rules in a given context" rather than in the question "what rules are to be applied.

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Specificities of French community gardens as environmental stewardships

Community-based efforts are essential to address urban social–ecological challenges. Here, we focus on French community gardens. Through participant observation and semistructured interviews, this study seeks to provide empirical evidence on: (1) what motivates volunteer gardeners in French community gardens to undertake this activity, (2) what practices take place in the gardens, and (3) which individual and collective processes are associated with gardeners' experiences in the gardens. Through these questions, we aim to understand how these initiatives relate to environmental stewardship. Our results show that environmental, social, and self-motivations are the drivers behind gardeners' participation in the gardens. It seems that involvement in the gardens provides opportunities to fulfill those needs and/or motives through different interrelated processes between the individual with him/herself, the human collective, and nature such as: contemplating nature and benefiting from sensory experiences, having access to environmental education, experiencing individual and collective organization, renewing social–ecological relationships, and facing local challenges. We note that French community gardens provide arenas for new experiences of nature. In addition, even if gardens’ biophysical features and gardening practices allow a series of processes that provide social and ecological benefits and outcomes, these gardens refer to environmental stewardship practices by cultivating relational values. These values provide opportunities for innovative ways of creative conservation, reflecting how care for ourselves extends to care for others, for places, and for nature.

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A Global Geospatial Ecosystem Services Estimate of Urban Agriculture

Though urban agriculture (UA), defined here as growing of crops in cities, is increasing in popularity and importance globally, little is known about the aggregate benefits of such natural capital in built-up areas. Here, we introduce a quantitative framework to assess global aggregate ecosystem services from existing vegetation in cities and an intensive UA adoption scenario based on data-driven estimates of urban morphology and vacant land. We analyzed global population, urban, meteorological, terrain, and Food and Agriculture Organization (FAO) datasets in Google Earth Engine to derive global scale estimates, aggregated by country, of services provided by UA. We estimate the value of four ecosystem services provided by existing vegetation in urban areas to be on the order of $33 billion annually. We project potential annual food production of 100–180 million tonnes, energy savings ranging from 14 to 15 billion kilowatt hours, nitrogen sequestration between 100,000 and 170,000 tonnes, and avoided storm water runoff between 45 and 57 billion cubic meters annually. In addition, we estimate that food production, nitrogen fixation, energy savings, pollination, climate regulation, soil formation and biological control of pests could be worth as much as $80–160 billion annually in a scenario of intense UA implementation. Our results demonstrate significant country-to-country variability in UA-derived ecosystem services and reduction of food insecurity. These estimates represent the first effort to consistently quantify these incentives globally, and highlight the relative spatial importance of built environments to act as change agents that alleviate mounting concerns associated with global environmental change and unsustainable development.

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School Gardens: A Qualitative Study on Implementation Practices

School gardens have beneficial effects on children's dietary behaviors but information on its implementation is scarce. The current study aimed to gain insight in implementation practices of school gardens and in perceptions of key members and children towards a school garden. We conducted twelve interviews involving 14 key members and five focus groups with 38 children from fifth to sixth grade (10-13 years old) in four primary schools in Ghent (Flanders, Belgium). We analyzed the interviews and focus groups in NVivo, using thematic analysis. School gardens were mainly initiated to involve children in nature, not to improve vegetable consumption. Participants were positive about having a school garden, experienced facilitating factors (e.g., adaptability of the garden, having a person responsible for the garden), but also various barriers (e.g., difficulties with startup, maintenance during summer holidays and integration in the school curriculum) and suggested some solutions (e.g., involving external organizations and parents, expanding the garden) and motivating factors for children (e.g., colorful plants, use of gloves). In order to improve implementation and to contribute to children's health, future school gardening projects should take the recommendations of key members and children into account.

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Rooftop farming on urban waste provides many ecosystem services

Urban farming, especially on rooftops, is a popular and growing topic in both the media and the scientific literature, providing a genuine opportunity to meet some of the challenges linked to urban development worldwide. However, relatively little attention has been paid to date to the growing medium of green roofs, i.e., Technosols. A better understanding of the influence of Technosols and the link with ecosystem services is required in order to maximize the environmental benefits of urban rooftop farming. Between March 2013 and March 2015, a pilot project called T4P (Parisian Productive rooftoP, Pilot Experiment) was conducted on the rooftop of AgroParisTech University. Urban organic waste was used, and results were compared with those obtained using a commercial potting soil, based on yield and trace metal concentrations, substrate characterization, and the amount of leaching. An assessment of the ecosystem services expected from the Technosols was undertaken in terms of the output of food (food production and quality), regulation of water runoff (quantity and quality), and the recycling of organic waste. Indicators of these ecosystem services (e.g., yield, annual loss of mass of mineral nitrogen) were identified, measured, and compared with reference cases (asphalt roof, green roof, and cropland). Measured yields were almost equivalent to those obtained from horticultural sources in the same area, and the Technosols also retained 74–84% of the incoming rainfall water. This is the first quantitative analysis of ecosystem services delivered by urban garden rooftops developed on organic wastes, and demonstrates their multifunctional character, as well as allowing the identification of trade-offs. An ecosystem services approach is proposed for the design of soil-based green infrastructure of this kind and more generally for the design of sustainable urban agriculture.

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Cartographie des jardins individuels à Longueuil (Québec, Canada)

En collaboration avec plusieurs partenaires, le Laboratoire sur l’agriculture urbaine (AULAB) travaille sur un projet d’évaluation de l’agriculture urbaine comme infrastructure verte de résilience individuelle et collective face aux changements climatiques et sociaux. Planifié sur trois ans (20176-2020), ce projet de recherche servira à outiller les acteurs sociaux québécois d’un guide d’évaluation sur les bénéfices de l’agriculture urbaine quant à l’insécurité alimentaire, la justice alimentaire et la résilience individuelle et collective pour l’alimentation, le tout dans un contexte de changements climatiques.

Le travail présenté dans le cadre de ce billet a été réalisé par Léa Brenneval de l’École Nationale des Travaux Publics de l’Etat, qui était en stage à AULAB à l’été 2017. Le stage  a été réalisé sous la supervision de Eric Duchemin, Directeur scientifique et formation de AULAB, avec la participation de Hien Pham, professeure à l’UQAM et Collaboratrice à AULAB.

Résumé : Dans le cadre d’une recherche l’équipe du Laboratoire sur l’agriculture urbaine (AU/LAB) a cartographié par Image satellite la présence de jardins individuels sur une première zone de 20,5 km2 du Territoire de la ville de Longueuil. Cette cartographie a été jumelée par des visites de terrain afin de valider l’identification effectuée par l’analyse des images. Cette zone d’étude couvre 18% du territoire de la ville de Longueuil. Continuer la lecture de Cartographie des jardins individuels à Longueuil (Québec, Canada) 

Agir pour les agricultures des aires urbaines : Guide d’aide à la décision

Cet ouvrage cherche à donner des outils de compréhension et d’action aux professionnels publics et privés (collectivités locales, entreprises, aménageurs, urbanistes, paysagistes, agriculteurs,…). sollicités sur ce sujet dans leurs métiers, il s’agit pour eux de partager une approche et un vocabulaire communs. À cette fin, le guide est organisé en trois grands chapitres : « Comprendre l’histoire » dresse le portrait de l’agriculture des aires urbaines en France, en présentant l’historique récent des relations entre la ville et l’agriculture, ainsi que la diversité des initiatives et les enjeux actuels. « Agir dans le Cadre des projets urbains » présente les facteurs clés à prendre en compte pour intégrer différentes formes d’agriculture urbaine dans l’espace et le temps urbains, avec les leviers d’action associés. « Agir dans le Cadre des politiques publiques » s’intéresse à la construction d’une stratégie agricole et alimentaire cohérente des collectivités urbaines, en décrivant notamment une démarche et en approfondissant des thématiques à mobiliser.

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Urban Gardeners’ Motivations in a Metropolitan City: The Case of Milan

Urban gardening (UG) as a component of urban agriculture (UA) has reached popularity during the last decades. This growing interest depends on several factors including the different functions that have been attributed to UG over the years, operating from the economic to the social, health and cultural levels. While multifunctionality of UG is well documented, only a few studies investigated individual gardeners' motivations, which can be subjective and heavily affected by the local context in which it takes place. The paper aims to detect some peculiar features of Milan city gardeners, in order to highlight the motivations of their activity through an innovative and replicable approach based on multiple correspondence analysis (MCA) and hierarchical clustering analysis (HCA). The analysis has been applied to the Milan case study, in the North of Italy; the results suggest a great importance of the social component of UG, and trace some different gardeners' profiles.

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Home-grown: Gardens, practices and motivations in urban domestic vegetable production

Food production is of symbolic and practical importance in sustainable cities. Vegetable gardening in public spaces and community gardens is better understood than the same activity on private residential property. In suburbanised western cities most vegetable production is likely to be on private blocks. To increase vegetable production in cities, we need to understand private vegetable growing. We used a questionnaire administered in person with a diverse sample of 101 gardeners in Hobart, Tasmania, Australia to determine variation in gardens, gardening practices and gardener motivations, relationships between them, and potential for planning and other interventions to increase domestic vegetable production. Vegetable gardens varied from highly species-rich to species-poor and from staple production to expressions of culinary fashion. Gardening practices varied from integrated, organic and displayed, to strongly constructed and reliant on synthetic inputs. While all respondents were motivated to grow vegetables for pleasure, many were activists who wished to promote social change, while others wished to ensure affordable access to vegetables or to improve health. Activist gardeners used integrated organic or permacultural practices and produced highly complex garden outcomes. With the exceptions of the activists and food fashionistas, garden type, gardening practice and gardener motivation were not strongly interlinked. A large majority of respondents identified family members as important sources of information and inspiration. Gardeners without family role models were either influenced by new food cultures or were on low-incomes and wanted affordable access to vegetables. This latter group could be expanded through appropriate education and incentives.

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Mapping public and private spaces of urban agriculture in Chicago through the analysis of high-resolution aerial images in Google Earth

Although always a part of city life, urban agriculture has recently attracted increased attention from diverse groups in the United States, which promote it as a strategy for stimulating economic development, increasing food security and access, and combatting obesity and diabetes, among other goals. Developing effective policies and programs at the city or neighborhood level demands as a first step the accurate mapping of existing urban agriculture sites. Mapping efforts in major U.S. cities have been limited in their focus and methodology. Focusing on public sites of food production, such as community gardens, they have overlooked the actual and potential contribution of private spaces, including home food gardens, to local food systems. This paper describes a case study of urban agriculture in Chicago which used the manual analysis of high-resolution aerial images in Google Earth in conjunction with ArcGIS to identify and map public and private spaces of food production. The resulting spatial dataset demonstrates that urban agriculture is an extensive land use type with wide variations in the distribution of sites across the city. Only 13% of sites reported to be community gardening projects by nongovernment organizations and government agencies were determined, through image analysis, to be sites of food production. The production area of home gardens identified by the study is almost threefold that of community gardens. Study results suggest opportunities may exist for scaling up existing production networks—including home food gardens—and enhancing community food sovereignty by leveraging local knowledges of urban agriculture.

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