Corn Moisture Measurement Accuracy

Abstract

The four electronic moisture meters most commonly used by Iowa grain dealers were compared with the official United States Department of Agriculture (USDA) air-oven method on 881 samples of corn from the 1979 and 1980 harvests. Samples ranged in moisture from 11% to 38%, wet basis. With the manufacturerdeveloped calibrations used in 1979, all four brands gave biased readings with respect to the air-oven method. Calibration bias errors differed among brands and ranged from approximately 1.5% to-3.5% moisture content. A recalibration between the 1979 and 1980 harvests reduced both this bias and the discrepancy among meter brands. Random errors originated from three sources: the electrical properties of different samples (contributing about 85% of the total random error), the repeatability of a meter test on a specific sample (contributing about 10%, and the repeatability of the oven method on a specific sample (contributing about 5%. The coefficient of variation of a meter test with respect to the oven varied with moisture content and increased from a minimum of 2.5% to 15.5% moisture corn to a maximum of 4.5% at both 11% and 38% moisture corn. Disciplines Agriculture | Bioresource and Agricultural Engineering Comments This article is from Transactions of the ASAE 28 (1985): 634-640. Posted with permission.

Quality Characteristics of Midwestern Soybeans

“…Test weight was associated with moisture (negatively), breakage susceptibility (negatively), and protein (positively). The test weight-moisture correlation is similar to, but much less certain, than the -0.8 reported from corn (Hall and Hill, 1973;Hurburgh et al, 1985). The negative association of test weight and breakage susceptibility means that denser kernels are generally more fracture-resistant.…”

“…Table 2 contains a summary of the pertinent statistics relative to the NIR calibrations. For comparison, Hurburgh et al (1985) reported that electronic moisture meters have a coefficient of variation relative to oven moisture of 3 to 4%. Soybeans from 1983 and 1984 were used for the GACIII calibrations.…”

Grain and Seed Moisture Sensing Applications

“…Accuracy of the moisture measurements required in the grain and seed trade has been achieved by continual improvement and calibration testing, but there is still some dissatisfaction with reliability in the higher moisture ranges, that is, above 20À25% for cereal grains. Recalibrations are also required occasionally because of differences in growing locations and variations in seasonal growing conditions (Hurburgh et al, 1985). An intensive study, with large numbers of samples for various grains and seed, of the variation in moisture readings due to influencing factors has been reported, and techniques were proposed Density dependence of the dielectric constant (ε 0 ) of shelled yellow-dent field corn at 24 C, 20 MHz, and indicated moisture contents (Nelson, 1979 (Funk et al, 2007).…”

Radiofrequency Sensing of Moisture Content in Cereal Grains

“…There have been numerous comparisons of commercial moisture-measuring instruments in the literature. Hurburgh and co-workers [38][39] compared the four most commonly used electronic moisture meters in Iowa, USA. They included the Steinlite SS-250, the Burrows 700, the Motomco 919, and the Dickey-john GACII.…”