https://ucanr.edu/county/cooperative-extension-ventura-county/portable-soil-moisture-meters-1993
Portable Soil Moisture Meters - 1993 | Cooperative Extension Ventura County
There are many ways of measuring soil moisture status - neutron probe, tensiometers, electrical resistance blocks, etc. - all of which have some limitations.
soil moisture meterscooperative extensionventura countyportable