A yield monitor system is configured to determine how the calibration characteristics of a grain mass flow sensor on an individual combine are affected by grain moisture content and/or other grain parameters which can be measured instantaneously or periodically by the yield monitor system or its operator, or which can be observed by the operator, or which can be determined from other reference information, such as maps of where different grain varieties or hybrids were planted. Other systems, methods, and apparatuses are also provided.
