Whether in the tropics or in temperate latitudes, pesticide residues in soils – in contrast to surface waters – have scarcely been investigated. To all intents and purposes, the effects of pesticides on soil organisms and the quality of arable soils have basically not been investigated over the long-term and under real-life conditions, and thus remain unknown. The PERECUSO (‘Influence of different pest management systems in potato production on PEsticide REsidues in CUban SOils’) Project which is financed by the Swiss National Science Foundation and the Swiss Agency for Development and Cooperation (programme r4d) represents an effort to investigate just this with our Cuban partners. Why the potato? Although the tropical climate is not ideal for potato growing, the tuber is in high demand on the island, and is very important for the tourism industry in particular.
Passed by the Swiss Federal Council in 2017, the Plant-Protection Product Action Plan inspired us to collaborate on this issue. The action plan provides for a reduction in the use of pesticides and in their emissions, in order both to halve the risks associated with pesticide use and to create a Swiss agricultural sector that is more resource-efficient overall. A programme for monitoring PPP residues in the soil is currently being developed by the Swiss Soil Monitoring Network NABO in partnership with the Environmental Analytics Working Group (Agroscope), the Ecotox Centre, EnviBioSoil and the Plant-Soil Interactions Research Group (Agroscope) in order to support this aim. A taking stock of the current situation will be followed by an examination of whether long-term monitoring of the risk posed by PPP residues for soil quality is possible, and if so, on the basis of which indicators.
Cooperation at international level allows us to arrive at a greater understanding of the behaviour of pesticides in the soil and in the environment, enabling us to monitor the breakdown of these products in both tropical and temperate regions, compare iron-rich soils in Cuba with loess-rich soils in Switzerland, and study different (e.g. organic vs. intensive) production systems in both countries.