Can the ECHO be used in soils at a depth between 0 – 5 cm?
The ECHO can be used effectively at shallow depths, but temperature fluctuations are a consideration. Inherent in ECHO measurements, as with TDR and other capacitance probes, is a temperature dependence of 0.003 m3 m-3 per degree C maximum, with typical of <0.001 m3 m-3 °C-1. Obviously, temperature fluctuations near the surface would be an issue in these measurements. The Echo Temperature Effect application note details a method of removing some of the temperature dependence.
