A tensioning system for maintaining the tension in a chain conveyor extended over at least one drive sprocket and one idler sprocket, and a method for maintaining the tension in a chain conveyor, in particular for example for a stalked crop harvesting header. The tensioning system comprises a first tensioning arm and a second tensioning arm rotatably connected to one another for rotation around a shaft onto which one of the sprockets is mounted, the second tensioning arm rotatably connected to a fixed point of a supporting plate, wherein the tension in the chain conveyor is maintained by rotational movement of at least one of the drive sprocket or the idler sprocket around a fixed point of the supporting plate.