Systems, methods and apparatus for monitoring yield while harvesting. In one embodiment a mass flow rate sensor measures the mass flow rate of the harvested grain. A weight sensor measures the weight of the harvested grain. The measured mass flow rate is correlated with the weight of the harvested grain. Processing circuitry calculates any error in the measured mass flow rate using the measured weight. The calculated error is used to correct any inaccuracy in the measured mass flow rate.
