Speeding up the Hay Drying Process

When we cut forage, it typically has 75-80% moisture which must be lowered down to about 14-18% to make dry hay. How are we able to get that moisture out, and what are the factors that affect hay drying? 

To ensure that you are getting every advantage you can to bale the crop as quickly as possible, there are several items you should take into consideration. The first step is to go to the field with your equipment ready to go. One of the best things you can do is check the clearance in your conditioning rolls. Roll clearance is the space between the rolls. If you have too large of a gap between the rolls, you will have under-conditioning. If the rolls are too close together and touch, conditioning rolls could wear out quickly, and also cause leaf loss. Learn how to determine your roll clearance at "Speed Up Hay Drying Time with Properly Adjusted Conditioning Rolls."

As you are mowing, consider laying the forage in as wide swath. According to research done by the University of Wisconsin, laying the crop in a wide swath that covers at least 60% of the cut area is the most important thing a producer can do to speed forage drying. This will minimize swath density and maximize the exposure to the sun. The drying of hay requires the removal of about three tons of moisture for every ton of hay produced. The energy equivalent of the sun drying the hay is about 70 gallons of fuel oil per ton. Also, if your ground is wet, a wide swath will also not lie as tight to the ground because the windrow is not as heavy.

Tedding is another way to speed up hay drying. Tedding lifts the crop off the ground and brings wetter forage to the surface, exposing it to the sun (Image 1). Both alfalfa and grass crops benefit from tedding, but you must also consider the disadvantage of losing leaves in alfalfa as the leaves dry.

Image 1: Tedding grass hay, exposing wetter forage to the surface. Photo credit: Dwane Miller, Penn State Extension

What if rain is on the way and the hay is still not at a moisture level appropriate for baling? Preservatives can be introduced into the windrow as hay enters the baler and are designed to slow down respiration by microbes when the hay is in the bale. More information on using preservatives for hay can be found at this University of Wisconsin fact sheet.

Finally, remember to monitor the temperature of hay that may have been baled at a higher than desired moisture level. If bale temperature is 125°F or lower, the hay should be safe. As temperatures climb higher, action should be taken to monitor bale temperatures, and move hay if possible. When hay reaches 175°F, the fire department should be alerted, and hay should not be moved without their assistance.