Early warning system : Regional soil monitoring tool for sustainable element cycles on agricultural soils

Fertilisers, pesticides and other soil amendments are applied to agricultural land. They contain, in addition to nutrients, small quantities of contaminants. The gradual accumulation of these substances and large nutrient surpluses represent a threat to soil quality and may impair soil functions. Regular monitoring provides important information on the status and trends of soil quality. However, this monitoring is rather costly in terms of time and resources and can only be done for a relatively small number of sites.

The project addressed the following key questions: How can nutrients and pesticide applications be optimised in the regional context? How can the input of contaminants to soils be reduced? How can we detect possible threats to agricultural soils over large areas?

The project team developed a regional modelling tool, consisting of a set of model components that analyses geo-referenced farm census data, land use maps, fertilisation guidelines, soil and weather data, and socio-economic factors. The team calculated inputs and outputs of nutrients (nitrogen, phosphorus) and trace metals (copper, zinc and cadmium) over recent decades in the soils of two case study areas in the cantons Zurich (41 km2) and Berne (158 km2). Spatially explicit maps of the element balances were generated. This made it possible to identify critical areas (“hotspots”) and predict future trends under different socio-economic scenarios.

The project focuses on the impact of regional agricultural management on soil functioning and facilitates decision-making on sustainable soil use. It takes an interdisciplinary approach, combining methods and data from different sectors. The results obtained can be a valuable resource in other fields as well, e.g. for assessing the diffuse pollution of surface waters.

A strength of the tool developed in the project is its capability to assess suitable measures towards sustainable agricultural land use through scenario analysis at the regional scale. It provides indicators to facilitate decision-making on sustainable soil management.

An integrated Modelling framework to monitor and predict trends of agricultural management and their impact on Soil functions at multiple scales (iMSoil)