Development and evaluation of a capacitance-type sensor for moisture measurement of baled forage

Moisture is one of the most important factors during and after the harvest in hay crops. Hay moisture content has a considerable impact on different stages of harvest and post-harvest such as baling, transportation, storage, etc, and therefore its role is very evident in production performance. The conventional method of moisture measurement of forage is by weighting method that is time-consuming and destructive. In this study, a capacitive sensor for real-time and continuous measurement of hay moisture content was designed, fabricated and evaluated. Alfalfa samples used in laboratory evaluation was obtained from alfalfa fields at research farm of College of Agriculture at Shiraz University, at three levels of moisture content, three levels of density and five levels of capacitor plates spacing. The results showed a significant relationship between moisture content and capacitance sensor’s output. Also temperature showed a significant effect on the sensor’s outputs.