A floating marker arm mechanism is disclosed. The marker arm mechanism comprises a bifolded marker arm pivotably mounted on a wheeled farm implement. The marker arm comprises first and second elongated members, pivotally connected together. The marker arm folds and is generally vertically disposed when not in use. When in use, the marker arm is extended outwardly from the wheeled implement and downwardly toward the ground. The marker arm mechanism of the present invention further includes a pivotable bracket removably affixed to the wheeled implement. The marker arm is pivotally mounted on the bracket. The bracket permits the arm to "float" between upper and lower positions when extended outwardly toward the ground to permit a marker disc mounted on the free end of the arm to follow ground contours if any.