Precise pesticide application—an earthworm field study

In the course of the advancing digitalization of agriculture, the precision application of pesticides is coming more and more into focus. Today's technology enables farmers to apply products only on spots or areas where needed. This leads to more heterogeneous pesticide spraying patterns compared with conventional full-area application. Consequently, soil organisms are exposed to correspondingly heterogeneous chemical stress regarding the field perspective. However, understanding how such "precise application" of pesticides affects soil organisms at the field level is limited, and these application methods are not yet standardized in pesticide regulation due to lack of concrete data. Therefore, an earthworm field effect study was conducted comprising standardized precision pesticide application patterns. Carbendazim was applied in a checkerboard design in three different scales with 50% treated and 50% untreated area. Results show that the earthworm community was less negatively affected in partially treated fields than blanket-sprayed fields. Further, results show that the scale of the spraying patterns matters, with the effects in the largest scaled pattern being less pronounced than in finer spraying patterns. Generally, treatments affected anecic earthworms more than endogeic earthworms. Additionally, anecic earthworms in the largest scaled spraying pattern did not show initial abundance decreases as they did in the two smaller scaled spraying patterns, indicating differences in responses of ecological groups to spraying patterns. This study is the first to demonstrate that application patterns matter. We aim to contribute to more sustainable pesticide use, integrating ecosystem services and providing baseline data for future soil risk assessments. Therefore, it would be desirable to have more empirical data on environmental risk assessment studies, especially compared with theoretical studies already available.