Using a Sensor to Test Hay Moisture - UNL CropWatch, June 3, 2011

Using a Sensor to Test Hay Moisture - UNL CropWatch, June 3, 2011

June 3, 2011

Getting hay baled at the correct moisture can be difficult, especially when it's cloudy or humidity is high.

Hay moisture testers inserted into a bale or windrow can provide a good indication of moisture levels, but need to be used with some care.  You need to know how the tester works, what causes values to vary, and how to use the tester most effectively.

Hay moisture testers measure the electrical resistance of the hay between two sensors. The more moisture, the less resistance. Then they convert this resistance to a value associated with average moisture content.

However, other hay characteristics can influence how testers sense moisture. For example, tight or dense bales, or even areas within a bale, will give different results than looser hay. Wiggling the probe or inserting it at an angle rather than straight into the bale changes the value. Also, hay with dew will give a much different value than hay without dew, even when overall moisture content is the same.

Testers can be a helpful tool if you take the time to use them for a while and learn what readings and what conditions indicate when to bale and when not to bale. Based on this experience, you'll be able to interpret readings accurately and get the guidance you need.

Bruce Anderson
Extension Forage Specialist