Different Techniques for Soil Moisture Measurement

A review of some of the techniques available for the determination of soil moisture content as a tension or a volume is offered. The method of determining soil moisture content by the different techniques is described with attention given to the neutron probe (NP), time-domain reflectometry (TDR) and frequency domain (Capacitance) techniques in particular. The choice of instrumentation for soil moisture determination will depend on the consideration of factors such as physical limitations of different techniques, the level of information required (either an absolute or relative moisture measurement), the amount of data needed to objectively decide upon an irrigation regime (with consideration to spatial and temporal problems), the initial cost of the instrument and sampling; the reliability of the instrument and the collected data, and, the ease of use of the instrument in the field.