Fig. 1: Illustration of the DEPHY network and data handling procedure.

a Geographical localization of the cropping systems considered in this study. Cropping systems (points) are colored depending on the climatic region to which they belong. Point size is proportional to the number of years the cropping system was monitored. b Cropping systems are defined as a set of fields within a farm that are subject to the same crop rotation, constraints, and decision rules (N = 1334). For a given cropping system, the diversity of the crop rotation can hence be captured at different time points (time points refers to either the two-to-three-year average provided by farmers upon entry in the network or the subsequent annual descriptions) through space-for-time substitution. c For each of the 16 main crops included in the cropping systems considered (N = 14,456), pesticide use was assessed using the treatment frequency index (TFI). TFI quantifies the number of pesticide applications at the full recommended dose. Total TFI was decomposed into herbicide, fungicide and insecticide TFI. d For each cropping system and time point (N = 3761), five diversity indicators were calculated and used as predictors for pesticide use at the crop level: functional diversity, taxonomic diversity, crop diversity, diversity of sowing periods and cover crop frequency.