The device i.e. agricultural sprayer (2), has a memory in which a program with operation modes of the device is stored. The program stored in an on-board computer determines that machining strips (3) on an agricultural surface (1) with current filling of a reservoir are still processed. An optical and acoustic signal is output to an operating person of the device by the computer when the strips are still processed and/or a fixed number of strips to be processed on the surface with current application rate is not fully processed under consideration of actual length of the strips.
