A method for controlling operation of an agricultural system, comprising - a tractor; - an implement hitched through a draw bar to the tractor, the implement having working tools configured to engage with a ground and / or an agricultural product in operation while the tractor is drawing the implement over a field; and - a control system, comprising a control unit and a sensor arrangement connected to the control unit through a control bus, wherein the control unit is configured to determine a draft force applied to the implement through the draw bar from measurement signals detected by the sensor arrangement; characterized in that the method comprises: - providing a first draft force threshold in the control unit; - providing a second draft force threshold in the control unit, the second draft force threshold being assigned a draft force which is higher than a draft force assigned to the first draft force threshold; - operating the implement in a normal mode of operation in which the working tools engage with the ground and / or the agricultural product while the tractor is drawing the implement over the field; - determining, by the control unit, that a present first draft force derived from first measurement signals detected by the sensor arrangement is higher than the first draft force threshold; - in response to the determining, - providing a warning signal in the control unit, and - outputting the warning signal to a user through an output device connected to the control unit; - determining, by the control unit, that a present second draft force derived from second measurement signals detected by the sensor arrangement is higher than the second draft force threshold; and - in response to the determining, - providing a switch control signal in the control unit; - outputting the switch control signal to an implement control unit; and - in response to the switch control signal, switching operation of the implement into a field transport mode of operation in which the working tools are disengaged from the ground and / or the agricultural product by lifting up the working tools while the tractor is drawing the implement over the field. - a tractor; - an implement hitched through a draw bar to the tractor, the implement having working tools configured to engage with a ground and / or an agricultural product in operation while the tractor is drawing the implement over a field; and - a control system, comprising a control unit and a sensor arrangement connected to the control unit through a control bus, wherein the control unit is configured to determine a draft force applied to the implement through the draw bar from measurement signals detected by the sensor arrangement; - providing a first draft force threshold in the control unit; - providing a second draft force threshold in the control unit, the second draft force threshold being assigned a draft force which is higher than a draft force assigned to the first draft force threshold; - operating the implement in a normal mode of operation in which the working tools engage with the ground and / or the agricultural product while the tractor is drawing the implement over the field; - determining, by the control unit, that a present first draft force derived from first measurement signals detected by the sensor arrangement is higher than the first draft force threshold; - in response to the determining, - providing a warning signal in the control unit, and - outputting the warning signal to a user through an output device connected to the control unit; - providing a warning signal in the control unit, and - outputting the warning signal to a user through an output device connected to the control unit; - determining, by the control unit, that a present second draft force derived from second measurement signals detected by the sensor arrangement is higher than the second draft force threshold; and - in response to the determining, - providing a switch control signal in the control unit; - outputting the switch control signal to an implement control unit; and - providing a switch control signal in the control unit; - outputting the switch control signal to an implement control unit; and - in response to the switch control signal, switching operation of the implement into a field transport mode of operation in which the working tools are disengaged from the ground and / or the agricultural product by lifting up the working tools while the tractor is drawing the implement over the field.