An assessment of soil nematode food webs and nutrient pools in community gardens and vacant lots in two post-industrial American cities

Abstract

In the midst of the current economic crisis, there is renewed interest in transforming vacant lots into food-producing gardens. This study analyzed whether vacant lots are suitable for food production, by comparing the soil nematode food webs and nutrient pools of vacant lots and community gardens in two post-industrial U.S. cities, Akron and Cleveland, Ohio. Twelve vacant lots and 12 community gardens were examined in the two cities. All six Akron community gardens were established just prior to the initiation of this study, whereas the six in Cleveland were 15-30 years old. Soil pH, texture, moisture, organic matter, mineral nitrogen content, microbial biomass, and nematode communities were measured in both cities. Soil decomposition rate was also measured in Cleveland. Results show that the soils of vacant lots surpassed those of the newlyestablished Akron gardens and were equal to the soils of the well-established Cleveland gardens in the amount of ammonium-nitrogen, total nematode population, genus diversity, and maturity and structure indices. The soils of the vacant lots were lower than the community gardens in the amounts of soil moisture, organic matter, and nitrate-nitrogen, which we associate with the addition of water, compost, fertilizer, and tilling in the gardens. No significant difference was found between community gardens and vacant lots in microbial biomass, decomposition rate, or nematode enrichment index, which seems to indicate that vacant lots are equal to community gardens in nutrient availability and nutrient cycling. We conclude that barring any contamination, the soil in vacant lots maybe suitable for the establishment of food gardens, which can provide many desirable ecosystem services and enhance human well-being. We also find that the disturbance associated with tillage and conversion of a vacant lot into a community garden has short-term ramifications for both nematode food webs and mineral-nitrogen content.

A Gardener's Influence on Urban Soil Quality

“…In contrast to the study carried out in urban forests of New York (Steinberg et al, 1997), we found no correlation between earthworm abundance and urban density. Moreover, we found higher decomposition rates in grass than in vegetables sites ( Table 3, Table S11), unlike Grewal et al (2011) who reported no differences in the decomposition rates between vacant lots, mainly consisting of grass sites and urban gardens, dominated by vegetables and fruits. With the modification of the TBI protocol given by Keuskamp et al (2013), we tried to minimize bias in mass loss due to small soil particles which could enter the mesh size of the tea bags.…”

“…This might be due to the enhanced microbial decomposer activity caused by the UHI effect (Craine et al, 2010). It has been proven that ecological gardening practices such as the application of organic inputs (Cogger, 2005;Sax et al, 2017) or less soil disturbance in gardens (Grewal et al, 2011) contribute to the above-ground biodiversity (e.g., Fuller et al, 2007;Sperling and Lortie, 2010). Further consequences on the nutrient cycle or soil quality are still poorly explored.…”

The Value of Urban Vacant Land to Support Arthropod Biodiversity and Ecosystem Services

“…Herein, we refer to these habitats as vacant land and concentrate on stud-ies examining previously built industrial or residential sites. As urban vacant land areas have expanded in U.S. cities, studies of arthropods and their functions have followed (Grewal et al , 2011Uno et al 2010;Yadav et al 2012;Gardiner et al 2013). We examine how knowledge gained from these and other studies of urban and suburban green spaces can aid in our understanding of urban ecosystem management.…”

The Public Value of Urban Vacant Land: Social Responses and Ecological Value

“…Studies have suggested that vacant land can provide many more ecosystem services than other urban land uses, such as gardens or lawns, including bio control [13], soil food web productivity [14], storm water retention services [15], habitat provision services, and climate regulation and carbon capture [16]. Vacant land vegetation can be a very cost-effective way of reducing the need for hard storm water management infrastructure and can also mitigate urban runoff by capturing a significant percentage of runoff [8,17].…”