Tools predicting pesticide leaching

Chemical pesticides used on fields can be diverted and transported away from the intended area through surface runoff or leaching down into the soil. Studies have found numerous occurrences of such substances in both surface water and groundwater in Norwegian agricultural areas. This contributes to soil and water pollution.

The path taken by pesticides in soil depends on factors such as weather, soil type, and the chemical properties of the substances. However, farmers have few tools to assess the likelihood of such pollution on their own farms.

Commissioned by the Norwegian Agriculture Agency, NIBIO has developed tables over a three-year project showing the probability of leaching of a pesticide sprayed on cereals and potatoes under specific soil and climate conditions. The aim is for farmers to use these tables to identify the most environmentally friendly option among the available pesticides.

The tables will be updated annually, and by 2023, similar tables will be created for several of the important agricultural crops in Norway.

"We have collected significant amounts of data on climate, soil, and crop development for potatoes/new potatoes and cereals (autumn and spring) in the four major agricultural regions in Norway, as well as data on all approved pesticides for these crops. Together, this forms the basis for model simulations that provide an indication of whether a pesticide can leach into groundwater and, if so, at what concentration," says Dr Roger Holten, project leader.

The results are summarised in tables showing pesticide concentrations down to two meters depth in all soil types for the cultivation of cereals and potatoes.