Date of Award


Document Type


Degree Name

Master of Science (MS)

Legacy Department

Plant and Environmental Science


Han, Young J.

Committee Member

Andrae, John G.


Three independent technologies related to hay yield monitoring were developed and studied. One technology involved comparison of infrared and ultrasonic sensors on a self-propelled forage harvester. Sensor response related to grass height and was used to estimate yield. Plots that were harvested ranged from 20-40 ft. in length while a bin mounted on the back of the mower collected the crop for weighing and sampling. The infrared sensors data demonstrated accuracies across plots between 5.9% and 9.5% error. The infrared sensors quickly deteriorated and eventually proved to be useless for data acquisition. As for the ultrasonic sensors, they demonstrated similar accuracy to the infrared sensors but the sensor response did not deteriorate like that of the infrared sensors. It was concluded that the standing crop method of yield monitoring would be difficult to adapt for commercial adoption but could potentially be beneficial in crop and machinery research. The same model sensors that were used on the self-propelled forage harvester were installed on a boom that was mounted to the tongue of a round hay baler to measure windrow height, which was then used to estimate mass flow rate and therefore crop yield. The infrared sensors proved to not be suitable for the environment from the beginning of testing due to the dusty atmosphere. Each hay bale was individually weighed by placing them on a platform that was sitting on truck scales. Samples were also taken from bales and dried to calculate moisture content. In year one, 59 bales of a Tifton 85 and Coastal mix were baled along with 57 bales of Tifton 85 and 9 bales of alfalfa. Average absolute error as calculated from sensor data acquired from the ultrasonic sensors ranged from 3.1% to 23.86%. Although the range is large, most of the average absolute errors stayed around approximately 10%. Year two data was also collected from ultrasonic sensors of a different model. The average absolute errors for those ultrasonic sensors ranged from 5.11% to 9.27%. In the third technology presented, a pressure transducer was installed on the hydraulic bale kicker circuit on two different round balers. The pressure transducer data was collected and correlated to bale weight to provide on-the-go bale weight estimates. Analyses were conducted to compare different size bales and bales that use different methods of wrapping. Average absolute errors for comparison of wrapping methods ranged from 1.1% to 7.28%. When combining the two methods, average absolute errors ranged from 2.44% to 9.46%. Average absolute errors ranged from 1.1% to 5.79% when data was analyzed within particular bale sizes.