![]() ![]() Maximum test weight is achieved when grain is harvested on the first dry-down and also at higher moisture. Although the grain may again dry in the field, the seed size does not change and the small voids inside the seed result in a decreased test weight. ![]() This process leaves small voids inside the grain. During germination, oil, starch, and protein are digested to provide energy and molecules to produce a new seedling. Grain matures and dries naturally in the field but is sometimes rewetted by rainfall, dew, or fog causing the grain to initiate the germination process (precocious germination) before harvesting.Artificial drying with heat removes this excess water but the starch molecules do not shrink and grain size doesn't change appreciably, so test weight (density) remains low. When this happens, the starch molecules inside the grain are prevented from the natural process of shedding absorbed water molecules that allow the grain to shrink to a normal size. Grain is prevented from filling completely and/or maturing and drying naturally in the field due to a killing frost, hail, or insect damage.Two common causes of low test weights are: Varieties of a crop often vary in their inherent test weight. grades for malting barley and oats are defined. USDA Test Weight Grade Requirements for Shelled Corn, Soft Red Winter Wheat, Barley, and Oats. The details of how test weight differs between grades for corn and more common small grains can be seen in Table 1. Other factors, such as cracked kernels, foreign materials, splits, and heat damaged kernels also contribute to grading standards. The test weight is also used in quality standards for small grains like soft red winter wheat, barley, and oats, but soybean grades are not impacted by test weight. The seller of grain with test weight greater than the acceptable range is usually not rewarded for a superior product. If the weight is lower than the acceptable range, the sale is "docked" on a percentage basis. Test weight is determined on each load of grain sold by weighing a known volume of the grain. 2 yellow corn has a standard of 56 pounds per bushel while No. Different grades of each grain have different standard test weights. When grain density is lower than the accepted standard (low test weight), more volume is needed to store and transport a given weight of grain, thus increasing storage and transport costs. The test weight concept was developed many years ago by the grain trade as a means of accounting for the varying densities of grain caused by weather and/or production practices. Some other examples are: Rye at 56 pounds per bushel, barley at 48, oat and fescue at 32, etc. Corn was assigned a bushel weight of 56 pounds, while soybeans and wheat were assigned bushel weights of 60 pounds. To facilitate the trading of grain, the USDA created weight standards for each grain so that grain could be weighed to determine the number of bushels rather than trying to make volume measurements. Although grain is referred to in terms of bushels in the United States, it is referenced and traded on the basis of weight (tons or metric tons) throughout the rest of the world. ![]() The bushel measurement was not defined in terms of cubic feet, but is currently considered to be about 1.25 cubic feet in volume. The objective of this fact sheet is to explain how and why grain test weight is used in the grain market, and how producers can ensure acceptable test weights from their crop production program.īushel is a volume measurement for grain created many years ago by Celtic peoples (Scotland, Wales, Brittany, Ireland) to facilitate fair grain trade. ![]()
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