Predicting the equilibrium moisture content
Horizon Point is a custom weather analysis system designed to help farmers with their daily business. Among the information that the program provides is a grain drying report, which predicts the equilibrium moisture content that would be reached by a crop exposed to ambient air conditions throughout the day.
The equilibrium moisture content — which varies by crop type — is the moisture content possible assuming that the crop is exposed to the air for a long enough period of time. The time required to reach the equilibrium moisture content depends upon the volume of air moved through the crop.
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.