The acoustic method of soil moisture measurement is based on the theory that the propagation of acoustic waves through a granulate such as soil is influenced by its moisture content. The speed of the acoustic waves in soil is proportional to the amount of water present. Acoustic methods are used to measure soil moisture content directly and give readings instantly to monitor soil moisture changes in real-time. Thus, it is a reliable and precise method.
There are a number of different acoustic methods that can be used to measure soil moisture content. One is the “through-transmission” method, which involves sending an acoustic wave through a soil sample and measuring the signal received on the other side. Another is the “reflection” method, which involves sending an acoustic wave into the soil and measuring the waveform reflected back from the soil surface.