Soybeans, from the 1983 and 1984 crops, were analyzed for official grade-factors, protein/oil composition, and breakage susceptibility. Samples were collected from 13 locations across four states. U.S. Grades did not differ greatly between years or sample origins, but nutrients and breakage susceptibility did. The average protein and oil percentages, basis 13.0% moisture, were 33.9, 19.7 and 34.2, 19.1 for 1983 and 1984 respectively. Several equations were developed to interrelate quality factors. For a one-percentage-point increase in protein content, there was an average decline of 0.43 percentage points of oil. This relationship varied by origin, with some origins showing less loss in oil for increase in protein. Breakage susceptibility, by the Wisconsin breakage tester, increased 22% for a one-percentage-point fall in moisture content.

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The long-term accuracy of the 1981 Iowa-Illinois moisture-meter calibrations was evaluated by meter-to-oven comparisons on 2999 samples from the 1979-1983 crop years. Although the five-year average accuracy of the trade meters Steinlite SS250, Dickey-john GACII, and Motomco 919 was ±0.5 percentage point relative to the air-oven up to 25% moisture (wb), there was up to ± 0.7 point accuracy variation among crop years. A year-toyear component was added to the previously published variance model; this component represents about 35% of total variance of a meter test relative to an oven test. Disciplines

Three farm-type moisture meters (Dickey-john DJMC, Dole 400-B, and Electrex DMT-2)* were compared to USDA-approved oven methods on 225 corn samples (10.4%-33.8% moisturet) and 96 soybean samples (8.0%-16.6% moisture) from the 1984 crop. In corn, the DJMC read ±0.5 percentage point of the oven up to 27% moisture. The 400-B read ±0.5 percentage point of the oven up to 28% moisture. The DMT-2 read equivalent to the oven at 11% moisture, but read progressively lower than the oven as moisture increased. At 25% corn moisture, DMT-2 read 4.4 percentage points less than the oven. In soybeans, DJMC tested a relatively constant 0.52 percentage points higher than the oven, 400-B read ±0.25 points, and DMT-2 varied linearly from 1.2 points high at 10% moisture to 1.5 point low at 17% moisture. Calibration correction equations are given for all three meters. Variability (with respect to the oven) of the farm-type meters increased as corn moisture increased, with an average coefficient of variation (CV) of 4.2%. Three trade-type meters, included for reference purposes, had an average CV of 2.4% on the same samples. In soybeans, variability was not a function of moisture content; the farm and trade meters had standard deviations relative to the oven of 0.37 and 0.26 points respectively. The major share of variability originated from sample-tosample variations in electrical properties, followed by differences among individual units of the same brand then variations among replicate meter tests and oven tests on a sample. Disciplines