Did you know that grain test weight plays a crucial role in the grain market? In this informative piece, we’ll delve into the significance of grain test weight, how it impacts the grain trade, and how producers can ensure acceptable test weights from their crops.
The Story Behind the Bushel
The bushel, a volume measurement for grain, was created by Celtic peoples centuries ago to facilitate fair grain trade. Although grain is commonly referred to in terms of bushels in the United States, the rest of the world trades and references grain based on weight. The USDA established weight standards for different grains to simplify trading. For instance, corn has a bushel weight of 56 pounds, while soybeans and wheat have bushel weights of 60 pounds.
The Importance of Test Weight
Test weight, a concept developed by the grain trade, accounts for the varying densities of grain caused by weather conditions and production practices. When the test weight is lower than the accepted standard, more volume is required to store and transport the same weight of grain. This leads to increased storage and transport costs. Different grades of each grain have different standard test weights, ensuring consistency and quality.
The Role of Test Weight in Grain Sales
Test weight is determined by weighing a known volume of the grain in each load sold. If the weight falls below the acceptable range, the sale is “docked” on a percentage basis. On the other hand, sellers of grain with test weights exceeding the acceptable range are not usually rewarded for their superior product. Test weight also influences the grading standards for small grains like soft red winter wheat, barley, and oats. However, soybean grades are not affected by test weight alone. Other factors, such as cracked kernels and foreign materials, contribute to the overall grading standards.
Table 1. USDA Test Weight Grade Requirements for Selected Grains
|Minimum Test Weight (lb/Bushel)
|Corn: 56, Wheat: 60, Barley: 47
|Corn: 54, Wheat: 58, Barley: 45
|Corn: 52, Wheat: 56, Barley: 43
|Corn: 49, Wheat: 54, Barley: 43
|Corn: 46, Wheat: 51, –
*Only four U.S. grades for malting barley and oats are defined.
Factors Affecting Test Weight
Varieties of a crop often differ in their inherent test weight. Two common causes of low test weights are:
Preventative Factors: Grain is hindered from fully filling, maturing, and drying naturally due to external factors like frost, hail, or insect damage. While artificial drying can remove excess moisture, it doesn’t significantly affect the density or test weight of the grain.
Moisture-Related Factors: Grain that matures and dries naturally in the field but gets rewetted by rainfall, dew, or fog can initiate the germination process prematurely. This can result in decreased test weight due to the small voids created inside the grain during germination. Maximum test weight is achieved when grain is harvested at the ideal moisture content for each crop.
Moisture Content and Test Weight
Grain is seldom sold at standard moisture levels, and adjustments must be made to account for the extra moisture content. If the grain’s moisture content exceeds the standard, the grain weight is discounted accordingly. For example, soybeans at 18 percent moisture would be adjusted using the formula: (100% – wet%) divided by (100% – dry%). This adjustment ensures fair compensation for the moisture content.
Ensuring Optimal Test Weights
To maximize test weight, it’s crucial to harvest grain at the right moisture levels. For soybeans, the ideal moisture content is 16-19 percent, while corn should be harvested at 20-25 percent moisture. By following recommended moisture guidelines, producers can optimize both test weight and the quality of their grain.
In conclusion, understanding the nuances of grain test weight is paramount in the grain market. Producers can enhance their crop production program by striving for acceptable test weights. So, why not take it up a notch and explore top-quality grain options from Rowdy Hog Smokin BBQ? They’re as passionate about their products as you are about your harvest. Happy farming!
Original content by Dr. Jim Beuerlein, Retired, Extension Agronomist (Originally published in 2000).