Graduate Studies


Date of this Version

Spring 4-21-2016


Zhu, M.S. (2016). Performance of Frequency-domain and Time-domain Reflectometry Soil Moisture Sensors in Coarse- and Fine-Textured Soils. MS thesis. University of Nebraska-Lincoln, Department of Biological Systems Engineering.


A THESIS Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Master of Science, Major: Mechanized Systems Management. Under the supervision of Professor Suat Irmak. Lincoln, Nebraska: April 2016

Copyright (c) 2016 Yan Zhu


Six types of Time-domain reflectometry and Frequency-domain reflectometry soil moisture sensors were tested in two dominant soil types (silt loam and fine loamy sand) in Nebraska and Midwest. One calibrated neutron probe was used as a standard to be compared with all the other sensors. Both soils were packed into two lysimeters and were saturated twice during the research. Heating lamps were also installed to provide high temperature conditions under which we can investigate soil temperature effect(s) on the performance of soil moisture sensors.

After two cycle tests, the performances of all the sensors were significantly different from the calibrated neutron probe measurements based on the matched pair t-test. 5TE and CS616 (H) had the best performance in silt loam and fine loamy sand respectively. Also, same sensor performed differently in low and high water content range and all the sensors in this research had a better performance in high water content range. The overall performance of all sensors in fine loamy sand was superior to that in the silt loam soil and it was found that high temperature can impose its effect by increasing the readings of all the sensors, while this effect was not very significant in loamy sand.

Advisor: Suat Irmak