Since 2009, the use of plant-protection products (PPPs) in field crops has been recorded annually as part of Switzerland’s agroenvironmental monitoring scheme. This information was used to calculate the amount of active substances applied per crop from 2009 to 2018, and to determine the quantity of active substances used in field crops throughout Switzerland, based on the cultivated areas specific to each crop. The risk potential posed to surface waters by this use of PPPs was analysed using the SYNOPS model. Over this period, the use of herbicides and fungicides in field crops declined steadily. Regarding insecticides, paraffin oil – an active substance used on potato crops – accounted for the bulk of applications. Without considering paraffin oil, the amount of insecticides used has also declined since 2012. The trend of the risk potential was constant for herbicides, downward for fungicides and upward for insecticides. Where the effects of the use restrictions for aquatic risk reduction imposed by the authorisation were also taken into account, a sometimes distinct reduction in all risk potentials was observed. Over the investigated period, there was a change in the spectrum of the PPP active substances available and used in field crops. It was found that some active substances, although used in smaller quantities, can be risk-dominant, while others, though used in larger amounts, have only slight effects on the risk potential for surface waters. The study shows that in field crops, the risk potential for surface waters changed over the course of the investigated period, mainly owing to the choice of PPP active substances and the increasing number of imposed use restrictions for reducing aquatic risks. An analysis of the risk in special crops requires a larger informational basis. Broader coverage, improved accessibility and increasing digitalisation in agriculture could contribute to the creation of a representative data pool for all crops in future.
