Soil indicators for sustainable planning

Soil provides numerous benefits through ecosystem services (ES), ranging from food provision over regulation of surface runoff to drug research and development, and has been cultivated over centuries. As such, it is a resource widely recognized as highly valuable – traditionally by disciplines closely working with soil such as agriculture but also increasingly by public discourse. Yet, soil is often marginalized as a two-dimensional surface in spatial planning, foregoing the importance of its third dimension: its quality.

Motivation

Soil quality is a feature hardly tangible due to its subsurface and invisible nature. Although various soil quality indicators exist, their specialization and orientation towards soil experts limit both practical applicability and communicative outreach. Moreover, the wide range of benefits soil provides is at the same time soil’s greatest strength and its greatest weakness: the multitude of benefits is what makes soil so precious a resource but it is also the reason why there is no single, objective soil quality indicator. In other words: comprehensive consideration of soil in spatial planning is stuck between conflicting, subjective use preferences.

Goal

Two soil quality indicators are developed. The first indicator, originally named BOKS (BOdenKonzept Stuttgart) adapts a tested and successfully applied approach from Germany to Swiss conditions. It is also used as a reference indicator to evaluate the performance of the second indicator. The second indicator, named SQUID (Soil QUality InDex) uses the ES concept to explicitly link soil to the benefits humans obtain from it. The idea is to combine relevant information on soil quality, information accessibility for both experts and non-experts, and effectivity for spatial development with the indicator’s ability to focus on “soil use” rather than on “soil potential”. This contributes to the overall goal of increasing communicative outreach of soil quality and facilitates the integration of soil into spatial development processes by fostering discussion among stakeholders about the various soil-derived benefits and their respective importance for any given project.