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 newly-established 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.