Simple grain moisture content determination from microwave measurements

Moisture content of wheat, Triticum aestivum L., is expressed as a function of the ratio of microwave attenuation and phase shift, measured at 16.8 GHz, and grain temperature. Validation of the calibration equation indicated that moisture content was obtained with an uncertainty less than +/-0.45% moisture at the 95% confidence level, independent of density variation, at temperatures from -1 degrees C to 42 degrees C, and moisture contents from 10% to 19%. Moisture determination does not depend on the layer thickness of the wheat nor its bulk density. No differences between two wheat cultivars were observed in the measurement data.