Density-independent moisture content measurement of wheat seed

Measurement of the capacitance and conductance of a capacitor filled with s amples of wheat allows the determination of two dielectric properties of th e material: the relative permissivity (epsilon'), and the dielectric loss f actor (epsilon "). The use of these two properties, measured simultaneously at two different frequencies of the electric field, permits bulk density-i ndependent measurement of moisture content of wheat. This procedure makes i t possible to monitor moisture content continuously, and online, of a movin g column of grain, a situation where the greatest variations in bulk densit y are to be expected. The objective of the present research was the derivat ion of density-independent equations for the determination of moisture cont ent of wheat. Samples of varieties Hussar, Mercia and Hereward at moisture contents ranging from 11% to 22% w.b., and bulk densities ranging from 666 to 873 kg m(-3) have been used. The best-performance equation was capable o f estimating moisture content of wheat with standard errors of calibration and prediction of 0.4 and 0.5 percentage point moisture, respectively.