Small-scale urban agriculture results in high yields but requires judicious management of inputs to achieve sustainability

McDougall, Robert; Kristiansen, Paul; Rader, Romina

doi:10.1073/pnas.1809707115

Cited by 171 publications

(122 citation statements)

References 44 publications

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“…Other scholars mostly confirm this finding [63]. When compared to traditional urban agriculture, which is considered to be resource inefficient in terms of labor and natural inputs [17,18], our results indicate that some of the high-tech urban agriculture approaches are still inefficient in terms of capital and energy demand. Local food production is not necessarily more environmentally friendly than national or global food systems, it always depends on the actual applied practices [9].…”

Section: Environmental Sustainabilitysupporting

confidence: 64%

How Will We Eat and Produce in the Cities of the Future? From Edible Insects to Vertical Farming—A Study on the Perception and Acceptability of New Approaches

et al. 2019

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Global challenges such as climate change, increasing urbanization and a lack of transparency of food chains, have led to the development of innovative urban food production approaches, such as rooftop greenhouses, vertical farms, indoor farms, aquaponics as well as production sites for edible insects or micro-algae. Those approaches are still at an early stage of development and partly unknown among the public. The aim of our study was to identify the perception of sustainability, social acceptability and ethical aspects of these new approaches and products in urban food production. We conducted 19 qualitative expert interviews and applied qualitative content analysis. Our results revealed that major perceived benefits are educational effects, revaluation of city districts, efficient resource use, exploitation of new protein sources or strengthening of local economies. Major perceived conflicts concern negative side-effects, legal constraints or high investment costs. The extracted acceptance factors deal significantly with the "unknown". A lack of understanding of the new approaches, uncertainty about their benefits, concerns about health risks, a lack of familiarity with the food products, and ethical doubts about animal welfare represent possible barriers. We conclude that adaptation of the unsuitable regulatory framework, which discourages investors, is an important first step to foster dissemination of the urban food production approaches.

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Section: Environmental Sustainabilitysupporting

confidence: 64%

How Will We Eat and Produce in the Cities of the Future? From Edible Insects to Vertical Farming—A Study on the Perception and Acceptability of New Approaches

et al. 2019

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“…Similar campaigns have been effective in reducing excessive fertilizer inputs to urban lawns, especially due to 'spillover effects' where citizens share information they have learned with their neighbors (Martini et al 2014, Martini andNelson 2015). As many UA practitioners may already be interested in sustainability (McDougall et al 2019), this population may be amenable to making behavioral changes that decrease negative environmental impacts from their actions.…”

Section: Discussionmentioning

confidence: 99%

Excess phosphorus from compost applications in urban gardens creates potential pollution hotspots

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Shrestha

Metson

et al. 2019

Environ. Res. Commun.

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Urban sustainability initiatives often encompass such goals as increasing local food production, closing nutrient loops through recycling organic waste, and reducing water pollution. However, there are potential tradeoffs among these desired outcomes that may constrain progress. For example, expansion of urban agriculture for food production may create hotspots of nutrient pollution if nutrient recycling is inefficient. We used gardener and urban farmer survey data from the Twin Cities Metropolitan Area (Minnesota, USA) to characterize phosphorus (P) and nitrogen (N) inputs and harvest in order to determine nutrient use efficiencies, and measured soil P concentrations at a subset of these sites to test whether excess soil P was common. All survey respondents (n=142) reported using some form of soil amendment, with plant-based composts being the most common. Median application rates were 300 kg P/ha and 1400 kg N/ha. Median nutrient use efficiencies were low (2.5% for P, 5.0% for N) and there was only a weak positive relationship between P and N inputs and P and N harvested in crop biomass. Garden soils had a median Bray P value of 80 ppm, showing a buildup of plant-available P far exceeding recommended levels. Our results show that urban gardens are characterized by high nutrient inputs and inefficient conversion of these nutrients into crops, leading to buildup and potential loss of P and N from garden soils. Although urban gardens make up only 0.1% of land area in the Twin Cities, compost application to these urban gardens still constitutes one of the largest inputs of P to the watershed. In order to maximize desired outcomes from the expansion of urban agriculture (UA), it will be necessary to target soil amendments based on soil nutrient levels and crop nutrient demand.

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“…Furthermore, compared with traditional open-field or greenhouse production systems, urban indoor growing systems may present increased water usage efficiencies. McDougall et al [68] also highlighted the need for UA projects to properly manage other resources beyond water (e.g., energy, chemicals) in order to be environmentally efficient activities.…”

Section: Contrasting the Evidence Of The Most Frequent Sustainabilitymentioning

confidence: 99%

How Can Innovation in Urban Agriculture Contribute to Sustainability? A Characterization and Evaluation Study from Five Western European Cities

et al. 2019

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Compared to rural agriculture, urban agriculture (UA) has some distinct features (e.g., the limited land access, alternative growing media, unique legal environments or the non-production-related missions) that encourage the development of new practices, i.e., "novelties" or "innovations". This paper aims to (1) identify the "triggers" for novelty production in UA;(2) characterize the different kinds of novelties applied in UA; (3) evaluate the "innovativeness" of those social, environmental and economic novelties; and, (4) estimate the links between novelties and sustainability. The study was based on the evaluation of 11 case studies in four Western European countries (Italy, Germany, France and Spain). The results show that the trigger and origin of new activities can often be traced back to specific problems that initiators were intended to address or solve. In total, we found 147 novelties produced in the 11 case studies. More novelties are produced in the environmental and social dimensions of sustainability than in the economic. In most cases, external stakeholders played an important role in supporting the projects. The analysis further suggests that innovativeness enhances the overall sustainability in urban agriculture projects.Goldstein et al. [7] defined UA as follows: "Most broadly, urban agriculture refers to growing and raising food crops and animals in an urban setting for the purpose of feeding local populations." Guided by this definition, we focus our research on this type of agricultural or horticultural production that is taking place either within the city or in very close proximity to it. UA as an InnovationDespite the early origin of UA in cities, it has often been considered an "innovative" way to address current urban problems. Therefore, this raises the following question: If UA is not new, why is it so often considered innovative? Pfeiffer et al. [8] indicated that many aspects of urban agricultural production are indeed very similar to those of small-scale rural farms and not entirely new, while other factors set UA apart from traditional agricultural operations. In their study, Pfeiffer et al. also described the distinct features of UA, such as the limited and nontraditional land access, the usage of urban soils and alternative growing media, the unique legal and political environments, the non-production-related missions, and the involvement of nontraditional farmers, which force the development of new practices. Prain and De Zeeuw [9] confirmed and complemented those findings by elaborating that the key factors for innovation in UA are those factors, such as multiple livelihood strategies, lower community cohesion, fewer possibilities for integrated agriculture, and quick market access, which differentiate urban from rural agriculture. They identified a direct correlation between urban settings and innovation processes in UA. Those specific conditions and characteristics drive urban operations to develop unique new practices adapted to the urban context.

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Small-scale urban agriculture results in high yields but requires judicious management of inputs to achieve sustainability

Cited by 171 publications

References 44 publications

How Will We Eat and Produce in the Cities of the Future? From Edible Insects to Vertical Farming—A Study on the Perception and Acceptability of New Approaches

How Will We Eat and Produce in the Cities of the Future? From Edible Insects to Vertical Farming—A Study on the Perception and Acceptability of New Approaches

Excess phosphorus from compost applications in urban gardens creates potential pollution hotspots

How Can Innovation in Urban Agriculture Contribute to Sustainability? A Characterization and Evaluation Study from Five Western European Cities

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