During urban expansion, soil is covered by roads, buildings and parking lots. This process, called soil sealing, impacts the ability of the soil to provide ecosystem services, such as supporting plant growth, filtering water and providing habitat. A recent study by the Department of Soil and Environmental Sciences investigates how urban development in Wisconsin has reduced the acreage of the state’s productive soils.

Between 2001 and 2021, Wisconsin’s population grew by almost 10%, while the extent of soil sealing increased by 20%. On average, 17 acres of soil were sealed each day, with 30 acres per day converted to urban land cover. Urban development primarily replaced agricultural land cover and disproportionately impacted soils with high agricultural productivity.

Statewide, the total area of cultivated crops was maintained, but there was a shift toward cultivating less productive soils. This could lead to greater reliance on external inputs like fertilizers and irrigation to maintain crop yields. Although advancements in crop genetics and agricultural management are key to food security, these depend on the availability of healthy soil and enough land for agriculture.

The study found that smarter decisions need to be made about how and where to develop land. This means protecting the best farmland soil, planning more compact cities with fewer impervious surfaces, revitalizing vacant lots and integrating nature-based solutions like permeable pavement. This Wisconsin story is part of a bigger global challenge: how to grow communities without compromising the land that sustains populations.

This study was funded through a Hatch project supported by USDA NIFA and was part of Annalisa Stevenson’s PhD studies. The published paper can be found here.