A row unit of a planter or other agricultural machine having ground engaging wheels is equipped with a rotation sensor to determine if and when a wheel stops rotating. An alert is issued by a monitor to the operator so that corrective action can be taken. Further, means are provided to determine when the machine is in used depositing an input versus turning at the end of the rows so that the rotation sensors to not generate an alert when the machine is not in use delivering an input to the field.
