University of Rhode Island DigitalCommons@URI Plant Sciences and Entomology Faculty Publications Plant Sciences and Entomology 2020 Modeling the Potential Productivity of Urban Agriculture and Its Impacts on Soil Quality Through Experimental Research on Scale- Appropriate Systems John R. Taylor Follow this and additional works at: https://digitalcommons.uri.edu/pls_facpubs ORIGINAL RESEARCH published: 07 July 2020 doi: 10.3389/fsufs.2020.00089 Modeling the Potential Productivity of Urban Agriculture and Its Impacts on Soil Quality Through Experimental Research on Scale-Appropriate Systems John R. Taylor* Department of Plant Sciences and Entomology, University of Rhode Island, Kingston, RI, United States Urban agriculture could play a central role in local and regional food sovereignty in developed countries, but in many cities, a lack of space and competition with other land uses limit production. Options for meaningfully advancing food sovereignty goals include sustainable intensification of existing urban farms and gardens; (2) expansion of production into interstitial and other underutilized spaces undevelopable Edited by: for other purposes; and (3) expansion of production in protected environments. Gaston Small, Observational studies suggest that–like smallholder agriculture in the Global South–urban University of St. Thomas, United States home, community, and market gardens in the developed world can be highly Reviewed by: productive–but often are not. Research on scale-appropriate systems and outreach James David Ward, to urban agriculturalists are needed to help them grow more food, more sustainably. University of South Australia, Australia This replicated, long-term trial is addressing this need—and a dearth of experimental, Houston Wilson, University of California, Riverside, normative research on urban agriculture—by evaluating the yield performance and United States impact on soil quality of four different systems of small-scale food production in Rhode Nicolas Jelinski, University of Minnesota Twin Cities, Island, the second most densely populated state in the United States and a potential United States model for the development of sustainable urban food systems. Systems are modeled on *Correspondence: vernacular systems in Providence, RI and Chicago, IL and on the scholarly and gray John R. Taylor literature on sustainable intensification. They differ in soil management practices and [email protected] nutrient sources. Results from the first 3 years of data collection indicate all four systems Specialty section: can be highly productive, with varying tradeoffs in terms of their sustainability and impacts This article was submitted to on soil quality. While total marketable food yields were relatively modest compared Agroecology and Ecosystem Services, −2 a section of the journal to those reported in the gray literature for biointensive agriculture−2.22–2.96 kg m Frontiers in Sustainable Food Systems averaged over three summer growing seasons compared to 4.64 kg m−2 for the “low Received: 05 February 2020 end” of biointensive production—yields for individual crops generally exceeded—and Accepted: 18 May 2020 Published: 07 July 2020 often far exceeded—regional averages and, for most crops and systems, national Citation: averages, without a loss in soil quality. In addition to demonstrating the high productivity of Taylor JR (2020) Modeling the small-scale systems compared to commercial farms, the study establishes a framework Potential Productivity of Urban for conducting normative, experimental research that can help to guide practice. It also Agriculture and Its Impacts on Soil Quality Through Experimental offers more reliable yield estimates for modeling the production potential of cities than do Research on Scale-Appropriate observational studies and agronomic experiments on monocultures. Systems. Front. Sustain. Food Syst. 4:89. Keywords: urban agriculture, sustainable intensification, ecosystem services, self-provisioning, urban food doi: 10.3389/fsufs.2020.00089 garden, home garden Frontiers in Sustainable Food Systems | www.frontiersin.org 1 July 2020 | Volume 4 | Article 89 Taylor Modeling UA Productivity INTRODUCTION a reduction in ecological niches and, consequently, biodiversity at higher trophic levels (Dewaelheyns et al., 2014; Taylor and Planners, academics, and food activists in developed countries Lovell, 2015; Taylor et al., 2017). At the same time, the literature increasingly recognize the potential role of urban to peri- suggests that the productivity, safety, and sustainability of urban urban agriculture in increasing local, state, and regional food agriculture could be improved without sacrificing—or even sovereignty (Alkon and Mares, 2012; Heynen et al., 2012; with enhancing—its cultural and ecological functions through Tornaghi, 2017). In the United States, New England’s 50 by 60 scale-appropriate, systems-based research, outreach to urban plan, for example, calls for meeting 50% of food needs through gardeners and farmers, and planning interventions designed to regional production by the year 2060 (Donahue et al., 2014). The encourage small-scale production (Beck et al., 2001; Witzling projected agricultural acreage required to meet this ambitious et al., 2011; Hunter et al., 2020). goal includes 20,000 acres of urban and 210,000 acres of suburban Unfortunately, agronomists, horticulturists, and other plant land (Donahue et al., 2014), much of it in the Northeast scientists have been largely absent from the scholarly discourse Megalopolis stretching from Washington, D.C., to Boston and on urban agriculture, and experimental agronomic research sheltering 18% of the U.S. population on 2% of the land base that could inform sustainable food production practices in (Yaro and Carbonell, 2018). While some U.S. cities, e.g., Oakland cities is thin despite repeated calls for such research (Wortman (McClintock et al., 2013), Chicago (Taylor and Lovell, 2012), and Lovell, 2013; Taylor and Lovell, 2014, 2015; Wagstaff and and Detroit (Beniston and Lal, 2012) may have large expanses Wortman, 2015). Fully replicated research on land-based, urban- of vacant land due to cycles of investment and disinvestment, scale production systems in the U.S. is limited to just four studies. such land is relatively scarce in other urbanized and urbanizing Miernicki et al. (2018) conducted a 2-years, ex situ factorial regions—including New England, the site of this research– experiment evaluating the impacts of different urban production because of development pressure. The city of Providence, Rhode systems on the yield of a limited number of crops (radish, kale, Island, for example, was estimated to have ∼476 city-owned cilantro, pepper, and garlic) from very small plots (1.5 m2). vacant lots in 2013 (Asen et al., 2014) compared to ∼19,500 city- Wagstaff and Wortman (2015) evaluated the performance of owned parcels in Chicago (City of Chicago., 2020). Land-based ten vegetable crops and measured variation in environmental urban production in more land-starved regions may be limited to variables at six sites, with replication, along an urban to peri- fragmented interstitial and other underutilized spaces, including urban transect in metropolitan Chicago. Beniston et al. (2016) residential lots. Existing production at this scale appears already evaluated the impacts of diverse amendments on soil quality and to make a far larger contribution to urban food systems than the yield of three crops (tomato, chard, and sweet potato) in a larger scale agroecosystems, such as urban farms (Taylor and replicated, in situ experiment conducted over a 2-years period in Lovell, 2012). a small U.S. city, Youngstown, OH. Small et al. (2017) examined Given constraints on land availability in many regions, options the effect of compost made from varying ratios of barley mash for meaningfully advancing food sovereignty goals through to woodchips on nutrient recycling efficiency and yield of two urban agriculture include: (1) intensifying production of existing crops, arugula and tomato, in a raised bed system over a single farms and gardens; (2) expanding the acreage of existing growing season. production through dispersed, small to very small-scale home Much larger is the literature based on observational and market gardens and farms on already developed land, on studies conducted by ecologists, entomologists, sociologists, residential lots and in interstitial and other unproductive, leftover geographers, and others. These studies have been productive spaces; and (3) expanding production in protected environments in characterizing the social, economic, and environmental ranging from unheated greenhouses (high tunnels) to more conditions of urban agriculture and the vernacular production technologically sophisticated–and resource-demanding–systems systems that have developed in response to those conditions. including hydroponic or aquaponic greenhouses and vertical Observational research indicates that land-based urban farms. Except for the use of high tunnels, increasing local food agriculture offers myriad challenges—and opportunities–which production through the third option is unlikely to increase make it distinct from rural agriculture. Research on commercial food sovereignty as defined by La Via Campesina: “the right of production in monoculture–the focus of most programs at U.S. farmers, peasants to produce food and the right of consumers to land grant universities–cannot simply be scaled down to an be able to decide what they consume, and