Horizon Point
       custom weather analysis

Horizon Point is a custom weather analysis system for farmers. It provides farmers with the opportunity to have site specific weather reports sent directly to their electronic mail address.

Example Grain Drying Report

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Horizon Point Grain Drying Report

The Horizon Point Grain Drying Report predicts the equilibrium moisture content that would be reached for a crop exposed to ambient air conditions hourly throughout the day. The equilibrium moisture content is the moisture content possible assuming the crop is exposed to the air for a long enough period of time. The equilibrium moisture content varies by crop type. The time required to reach the equilibrium moisture content depends upon the volume of air moved through the crop.

Natural Air Grain Drying

Natural air drying in Missouri will eventually reduce the moisture of a stored crop below the market moisture content of the crop. Over-drying removes saleable moisture and reduces the total weight of the crop. The goal of the drying process is to reduce the entire bin to a uniform moisture content suitable for short-term storage and without drying charges deducted at time of sale.

The recommendation for in-bin natural air drying is to run the fan continuously until the top layer of the crop has reached the final desired moisture content. The bottom layers of grain will become dry first and will typically become overly dried especially if the fan is operated only during the very driest conditions of the day.

The capacity of the air to hold moisture changes throughout the day. Air during the afternoon portion of the day has more capacity to remove moisture from a crop than at any other time. The drying capacity of the air is reduced at night when temperatures drop and the air becomes more saturated. When the air reaches 100% humidity, the air is holding as much moisture as is possible. Whenever the predicted equilibrium moisture content of the air with respect to a particular crop is greater than the moisture content of the crop, rewetting can occur. Rewetting grain is typically a slower process than drying grain.

Dry grain at the bottom of the bin acts as a desiccant when the fan continues to run during high humidity conditions that occur during the nighttime hours. As the air passes through the bottom layer of grain it becomes dry enough to remove some moisture from the grain above. Hence, moisture content continues to change throughout the profile of the bin and results in a more even moisture profile when the fan continues to run even through the nighttime hours. Continuous aeration also prevents runaway heating as it drives off heat that might occur from the activity of storage fungi in wet grain.

Determining the need for supplemental heat

During continuous periods of high humidity that might occur during a stationary weather front that has the potential to produce rain, natural air drying may not be possible. Prolonged periods when the predicted equilibrium moisture content is above the moisture content of the grain at the bottom of the bin will result in spoiled grain. A small amount of heat on the order of 5 to 10 degrees F can restore drying capacity of the air in most cases during these periods. Alternatively, fans can be stopped for a short period of time until the condition of the ambient air is sufficient to continue drying.

Long periods without aeration of wet grain are not advised. Check grain frequently and monitor temperature of the grain to avoid heating. Continuous aeration helps redistribute moisture to reduce overdrying of grain at the bottom of the bin during normal diurnal patterns. Continuous aeration also protects undried grain at the top from runaway spoilage processes from storage fungi. The cost running the fan continuously even though little drying may occur is relatively small compared to the cost of dealing with spoiled grain.

Shallow layers of grain are always less susceptible to spoilage than deep layers because they will dry more quickly. Stirring devices can keep the moisture content profile within the bin to more uniform levels. Selective fan operation based on weather data is more feasible in stirred bins.

PRECISE information

           PROCESSED by MU Extension

                          for better MANAGEMENT decisions

Should you have any problems with setting up an account or finding the latitude and longitude for your field, contact Horizon Point at 573-882-4827 or HorizonPoint@missouri.edu.