TAKING INTO ACCOUNT THE MULTIFUNCTIONALITY OF SOILS IN LAND USE PLANNING

Potentially densifiable land where a community garden has been established, Schoenberg, Fribourg 
© AgriUrbs team photo, April 2024

Agricultural spaces located near or within cities are among the most vulnerable open soil areas when faced with the demands of urban densification. Seen as land reserves, these spaces also fulfill a wide range of essential functions for living beings. They support food production, biodiversity conservation, water management, the mitigation of urban heat islands, soil erosion control, and air filtration. Additionally, these areas serve as valuable resources for recreational activities that contribute to the quality of life in urban environments.

The AgriUrbs project aims to develop a method for better integrating the multiple functions of soils (food production, health, ecological, economic, and social) into land use planning. Its objectives are:

• to identify the pressures exerted on agricultural and open soil spaces in dense urban and suburban contexts
• to demonstrate the capacity of these spaces to contribute to the resilience of territories in the face of current and future climate challenges.

The project provides a cartographic assessment of construction activities carried out between 2015 and 2024 in the most densely populated municipalities of the agglomeration (Fribourg, Marly, Villars-sur-Glâne, Givisiez, Belfaux, Granges-Paccot, Matran, and Corminboeuf). This assessment highlights both the loss of land used for agricultural purposes and the loss of open soil surfaces within urban areas over the past 10 years.

Loss of open soil surface between 2015 and 2024.
Situation on the urban fringe (Corminboeuf) and within the built-up area (Schoenberg, Fribourg).
© SWISSIMAGE et Voyage dans le temps – images aériennes (Office fédéral de topographie swisstopo)

Following this diagnostic phase, three sites within the Fribourg agglomeration were selected as the experimental foundation for the project, all designated for densification.

These three case studies will enable the testing of various potential scenarios for food production, aiming to better utilize the multifunctionality of open soil spaces in urban planning. This will be done using urban planning indicators (density, impermeabilization, tree coverage) and a Soil Quality Index (SQI). The food production scenarios will be compared to the densification scenarios planned for these sites.

The project aims to provide a decision-making tool for urban planning professionals by developing a method to evaluate the functions lost and gained in the event of urbanization of an open soil site. An interdisciplinary expert committee is also involved in the project.