does corn test weight improve during dry down


Introduction to Corn Test Weight during Dry Down

Corn test weight refers to the weight of a specific volume of corn, usually given in pounds per bushel. Many factors can influence corn test weight, including genetics, environmental conditions, and management practices. One question that often arises is whether corn test weight improves during the dry-down period. In this article, we will explore the relationship between corn test weight and the process of drying down, shedding light on this intriguing topic that affects corn growers and researchers alike.

The Dry Down Process: What Happens to Corn?

During the dry-down period, corn experiences a series of physiological and biochemical changes. At this stage, the corn kernels gradually lose moisture, changing their composition and physical characteristics. Initially, the corn goes through a period of physiological maturity when the kernels are fully developed and reach maximum dry matter accumulation. After this stage, the corn begins to lose moisture through transpiration and evaporation.

The dry-down period is influenced by various factors, such as temperature, humidity, and air movement. Under optimal conditions, corn can lose moisture at a rate of 1 to 2 percentage points per day. The moisture content of corn kernels directly affects their weight, density, and quality.

Understanding Corn Test Weight: Its Significance and Measurement

Corn test weight carries considerable importance for corn growers, buyers, and processors. It serves as a measure of grain quality and density, indicating the amount of dry matter per unit volume. Higher test weights generally indicate denser kernels with less void space, suggesting better kernel quality and increased market value.

Test weight is typically measured in pounds per bushel, representing the weight of a bushel of corn at a standardized moisture content. In the United States, the standard moisture content used for test weight determination is 15.5%. Corn kernels at this moisture level are assumed to have reached equilibrium with the surrounding environment, allowing for consistent comparisons.

The Relationship between Dry Down and Corn Test Weight

The relationship between dry-down and corn test weight has long been a topic of interest for researchers and corn producers. Understanding this relationship can help growers make informed decisions regarding harvest timing and grain management practices.

During the dry-down process, corn kernels lose moisture, which contributes to a reduction in kernel weight. As moisture content decreases, the density of the kernels increases, potentially leading to improved test weight. However, it is important to note that this relationship is not always linear. Numerous factors influence corn test weight during dry down, making it difficult to predict precise outcomes.

Factors Affecting Corn Test Weight during Dry Down

Several factors can influence corn test weight during the dry-down period. Understanding these factors is crucial for growers seeking to optimize their harvest timing and grain quality. Let's explore some of the key factors that can impact corn test weight:

1. Genetics

Genetics play a significant role in determining corn test weight potential. Different corn hybrids exhibit varying levels of test weight, with some genetics naturally predisposed to higher test weights than others. Hybrids with larger kernels and higher kernel densities tend to have a higher test weight potential.

Though genetics provide a foundation, it is important to remember that environmental conditions and cultural practices can also impact test weight. Therefore, growers should select hybrids with desirable genetics and adapt their management practices accordingly.

2. Environmental Conditions

Environmental conditions, particularly temperature and humidity, can greatly influence corn test weight during the dry-down period. Warm and dry conditions usually accelerate the rate of moisture loss, potentially leading to better test weights. Conversely, cool and humid conditions can slow down the drying process, resulting in lower test weights.

However, extreme or prolonged stress caused by drought or other adverse weather conditions can negatively impact test weight. It is essential to strike a balance between favorable environmental conditions and avoiding extreme stress to maximize test weight during dry down.

3. Maturity at Harvest

Harvesting corn at the appropriate stage of maturity is crucial for optimal test weight. If corn is harvested too early, the kernels may not have reached their maximum dry matter accumulation, resulting in reduced test weight potential. On the other hand, delaying harvest beyond physiological maturity can lead to kernel dry-down, increasing the potential for kernel damage and loss, which can negatively impact test weight.

Timing is crucial, and growers should closely monitor the progress of corn development to determine the optimal harvest date for maximal test weight potential.

4. Grain Moisture Management

Effective grain moisture management also contributes to achieving better test weights during the dry-down period. Proper drying and storage practices minimize moisture variations and allow corn to reach a consistent moisture level throughout the grain mass.

Harvesting corn at the optimal moisture content, using appropriate drying techniques, and ensuring proper storage conditions are essential for preserving test weight. Careful monitoring and management of moisture levels can help preserve the quality and test weight of corn during the drying process.

5. Post-Harvest Handling

Post-harvest handling practices, such as transportation and handling equipment, can influence corn test weight. Rough handling and mechanical damage to the kernels can reduce test weight, as damaged kernels may have decreased density. Using appropriate equipment and gentle handling techniques can help maintain test weight and preserve grain quality.


In conclusion, the relationship between corn test weight and the dry-down process is complex, influenced by a variety of genetic, environmental, and management factors. Though dry-down generally results in reduced moisture content and increased kernel density, the precise impact on test weight can vary. Therefore, growers should consider multiple factors, such as genetics, environmental conditions, maturity at harvest, grain moisture management, and post-harvest handling, to optimize corn test weight during the dry-down period.

Understanding these factors and their interactions will enable corn producers to make informed decisions about when to harvest their corn and implement appropriate management practices to preserve and maximize test weight. By doing so, growers can improve grain quality, enhance market value, and ultimately achieve greater success in their corn production endeavors.


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