An agricultural system comprising: a plough that includes a plough body, the plough comprising: an actuator that comprises a stone-trip-actuator, wherein the stone-trip-actuator is for applying a bias force to the plough body of the plough such that it is biased towards a working position; a location-determining-system associated with the plough, wherein the location-determining-system is configured to provide implement-location-data that is representative of a current location of the plough; and a controller that is configured to: receive one or more trip-locations, wherein the one or more trip-locations are locations of a second plough at a time that a stone-trip-mechanism has tripped in an earlier agricultural operation; receive the implement-location-data; determine a ground-engaging-tool-location based on the implement-location-data, wherein the ground-engaging-tool-location represents a current location of the plough body; and process the ground-engaging-tool-location and the one or more trip-locations in order to provide an actuator-control-signal to the stone-trip-actuator, wherein the actuator-control-signal is configured to decrease the bias force that is provided by the stone-trip-actuator based on the result of a comparison between (i) the difference between the ground-engaging-tool-location and the trip-location, and (ii) a distance-threshold in order to control the operation of the stone-trip-actuator. a plough that includes a plough body, the plough comprising: an actuator that comprises a stone-trip-actuator, wherein the stone-trip-actuator is for applying a bias force to the plough body of the plough such that it is biased towards a working position; a location-determining-system associated with the plough, wherein the location-determining-system is configured to provide implement-location-data that is representative of a current location of the plough; and a controller that is configured to: receive one or more trip-locations, wherein the one or more trip-locations are locations of a second plough at a time that a stone-trip-mechanism has tripped in an earlier agricultural operation; receive the implement-location-data; determine a ground-engaging-tool-location based on the implement-location-data, wherein the ground-engaging-tool-location represents a current location of the plough body; and process the ground-engaging-tool-location and the one or more trip-locations in order to provide an actuator-control-signal to the stone-trip-actuator, wherein the actuator-control-signal is configured to decrease the bias force that is provided by the stone-trip-actuator based on the result of a comparison between (i) the difference between the ground-engaging-tool-location and the trip-location, and (ii) a distance-threshold in order to control the operation of the stone-trip-actuator. receive one or more trip-locations, wherein the one or more trip-locations are locations of a second plough at a time that a stone-trip-mechanism has tripped in an earlier agricultural operation; receive the implement-location-data; determine a ground-engaging-tool-location based on the implement-location-data, wherein the ground-engaging-tool-location represents a current location of the plough body; and process the ground-engaging-tool-location and the one or more trip-locations in order to provide an actuator-control-signal to the stone-trip-actuator, wherein the actuator-control-signal is configured to decrease the bias force that is provided by the stone-trip-actuator based on the result of a comparison between (i) the difference between the ground-engaging-tool-location and the trip-location, and (ii) a distance-threshold in order to control the operation of the stone-trip-actuator.