Calculation of the official NODU indicator from sales of active substances (Eq. (1)) is not based on the individual contribution of each crop to total pesticide use. This contribution is in fact not measured in France, because the crop for which a given pesticide is purchased is not identified and recorded at the time of sale and because the same active substance can be applied to different crops (e.g. sulfur can be used against wheat powdery mildew, grapemildew, or apple scab).Capturing the impact of agricultural land use changes on the NODU indicator thus requires calculating this indicator in a different way, relating it directly to agricultural land area devoted to each crop combined with pesticide use on each agricultural landarea, that is: