There are many soil moisture probes and sensors on the market that sample moisture in very isolated volumes of soil and can log these over time but cost effective tools that image changes in soil moisture, in a whole vertical section or even in 3D in the soil are rare.
Movement of moisture and changes in salinity can be imaged over time using our ERT (electrical resistivity tomography equipment) optionally with telemetry. It is useful for monitoring pollutants & for study of irrigation efficiency. A typical agricultural installation will integrate moisture probes and/or Granular matrix moisture sensors within it. Indeed our system, with the Lippmann Geo-resistivity meter at its core can directly measure moisture changes both within numerous granular matrix moisture sensors and between them and strategically placed electrodes set up so as to image, using tomography, a large bulk of soil. The Lippmann Geo-resistivity meter communicates directly with terminal modems to regularly transmit data to the internet.
A typical pollution plume monitoring setup will use the same equipment but with electrodes buried in trenches, typically beneath and beside plastic lined reservoirs containing the pollutants. A reservoir set up with such monitoring in advance is a good idea.