Use of a Dielectric Tensiometer and Other Soil Moisture Sensors to Measure Soil Drying by Roots of Wheat.

Measurement of the matric potential of soil water is central to almost all studies of water movement and plant stress responses. However, in comparison with advances made in the measurement of soil water content, there has been slow progress in the development of improved methods to measure matric potential. This poster compares the output of dielectric tensiometers (Whalley et al. 2009) with other soil moisture sensors in soil sown with rain-fed and irrigated wheat. We provide clear evidence to show that for research purposes the use of a range of different types of sensors including water-filled tensiometers, soil water content sensors and dielectric tensiometers gives best results. While water-filled tensiometers are direct reading, which is appealing, they do not work well over the wide range of matric potentials relevant to rain fed crops. For more general applications (i.e. non-research) dielectric tensiometers provide a useful solution to measuring the matric potential of soil water.

 Further reading:

Whalley, W.R., Lock, G., Jenkins, M., Peloe, T., Burek, K., Balendonck, J., Take, W.A., Tuzel, İH. and Tuzel, Y. (2009) Measurement of low matric potentials with porous matrix sensors and water-filled tensiometers. Soil Science Society of America Journal. 73 :1796-1803