A monitoring device for monitoring crop yield, the monitoring device comprising: a mounting structure configured to be mounted to a housing of a grain elevator of an agricultural work machine, the mounting structure comprising at least one aperture formed therein; a fulcrum assembly arranged on the mounting structure , the fulcrum assembly having a pivot point ; a material engagement member at least partially disposed within the aperture, the material engagement member being pivotal with respect to the mounting structure about the pivot point of the fulcrum assembly , the material engagement member having a first end and a second end opposite of the first end ; a rotational sensor coupled to the fulcrum assembly , wherein the at least one rotational sensor is configured to detect spatial movement or position of the material engagement member and output a signal corresponding to a rotational magnitude of displacement of the first end or second end of the material engagement member relative to the pivot point , wherein the displacement is induced by the exertion of a force generated by an agricultural material engaged with a surface of at least one of the first or the second end of the material engagement member , and wherein the displacement of the first end or second end is proportional to a degree of pivotal movement of the material engagement member about a pivot point axis; and a processing device coupled to the rotational sensor and configured to determine a mass flow rate of the agricultural material based on the detected rotational magnitude of the displacement of the first end or second end , and wherein an aggregate crop yield is determined based on the mass flow rate. a mounting structure configured to be mounted to a housing of a grain elevator of an agricultural work machine, the mounting structure comprising at least one aperture formed therein; a fulcrum assembly arranged on the mounting structure , the fulcrum assembly having a pivot point ; a material engagement member at least partially disposed within the aperture, the material engagement member being pivotal with respect to the mounting structure about the pivot point of the fulcrum assembly , the material engagement member having a first end and a second end opposite of the first end ; a rotational sensor coupled to the fulcrum assembly , wherein the at least one rotational sensor is configured to detect spatial movement or position of the material engagement member and output a signal corresponding to a rotational magnitude of displacement of the first end or second end of the material engagement member relative to the pivot point , wherein the displacement is induced by the exertion of a force generated by an agricultural material engaged with a surface of at least one of the first or the second end of the material engagement member , and wherein the displacement of the first end or second end is proportional to a degree of pivotal movement of the material engagement member about a pivot point axis; and a processing device coupled to the rotational sensor and configured to determine a mass flow rate of the agricultural material based on the detected rotational magnitude of the displacement of the first end or second end , and wherein an aggregate crop yield is determined based on the mass flow rate. <EOS>