Could a Detroit Experiment Unleash the Power of Urban Soil?
A multi-year study underway aims to build healthy urban soil quickly at minimum cost, yielding local, fresh food and climate mitigation as a bonus.
By Brian Allnutt
Civil Eats
July 16, 2020
On 36 ten-by-five-foot plots, the project is evaluating how cover crops, compost, tillage, and other forms of cultivation can work together to improve a piece of land. Researchers are measuring factors like soil organic matter, water infiltration, compaction, and weed abundance to see how they change over time.
Although the ground under cultivation is fairly typical of Detroit’s heavy, alkaline soils, it probably mirrors conditions in other cities as well. And while the study does not address outright contamination, some research has emerged showing that, at least when it comes to heavy metals, vegetables from contaminated soils are generally safe, although direct exposure to the dirt through dust or root crops remains a problem.
“My goal is in five to 10 years, to be able to push my fingers into this, which [now] is impossible,” Edwards says, indicating the ground beneath him. “You can barely push a knife it into this soil.” Tests at the site also show a pH of 8.1 to 8.4, which is high even by Detroit standards. A slightly acidic pH of 6.5 is ideal for most vegetables.
Edwards received input on the project from a number of urban farms and community gardens in Detroit, including Brother Nature Produce, Earthworks Urban Farm, and the Georgia Street Community Collective. Many of these growers shared similar concerns about the alkalinity of urban soil—which is sometimes produced by concrete—as well as its compaction and the high cost of inputs like compost and organic fertilizers.
