Degree Type


Date of Award


Degree Name

Doctor of Philosophy


Agricultural and Biosystems Engineering


In the grain trade, electronic moisture meters are used for most moisture content determinations. These meters provide a fast indication of moisture content by measurement of certain electrical properties of grain, most often dielectric constant;The objective of this study was to quantify the effect of corn variety, harvest damage, and drying temperature on the accuracy and precision of electronic moisture meters;Four moisture meters were compared to the official air-oven method on 243 samples of corn. The moisture meters used were Steinlite SS250, Burrows 700, Motomco 919, and Dickeyjohn GACII. Three corn varieties studied for meter accuracy and variability were Iowa State Hybrid M110, Martinson SX440, and Pioneer 3541. Three shelling methods used in this study were hand, normal, and severe combine shelling. The corn samples were initially tested wet, then dried to about 15% moisture by both natural air (at about 20 C) and heated air (at 832 C);Corn variety and shelling methods had significant effects on the relative accuracy of the meters with respect to the oven. Drying air temperature did not affect the moisture meter accuracy;In dry corn, the meters tested higher relative to the oven with the variety Iowa State Hybrid M110 than the other two varieties. There was no significant difference in performance between Martinson and Pioneer. The Iowa State was the highest in test weight, the lowest in dye index, and the lowest in Stein breakage percentage (in both dry and wet corn) and the lowest in BCFM and large broken percentage;Shelling methods contributed significantly to meter errors. Hand-shelled corn tested highest relative to the oven, followed by normal combine and then severe combine. Test weight followed the same pattern as meter errors with hand-shelled the highest and severe combine the lowest. Percent BCFM, dye index, and Stein breakage were in reverse order;Meter calibrations were consistent with respect to each other. The Motomco moisture meter had the least susceptibility to the effect of the three treatments studied.



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Copyright Owner

Medhat Abdalla Hemeda



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131 pages