One high-capacity clip-on pump is driven via the gearbox output of the tractor and provides the necessary hydraulic pressure for a tractor independent circuit on the seed drill. The control valves for the regulation of the coulter pressure and for raising the main frame on the headland are operated from the driver’s seat. These are the mostly used functions and are combined with the tractor own circuit. In most cases, the control valve for folding the wings is only used when starting and finishing work. Therefore this is implemented, in the same way as the on/off control of the blower fan via a separate control block on the seed drill. As only two hydraulic sections are directly connected to the tractor’s circuit, the danger of pollution due to dirty hydraulic oil is clearly reduced.