Penetrometers are a vertical force sensor that provides information on soil mechanical resistance throughout the soil profile. The penetrometer typically consists of a cone that is forced through the soil using hydraulic actuation. Sensors are used to measure penetration resistance (e.g. load) and penetration depth. It is a well established technique.
Current research is focused on incorporating additional sensors into the penetrometer cone for in-situ profile measurements of other soil attributes (e.g. cameras, spectrometers, XRF, LIBS, acoustic etc).
Cone penetrometers with integrated optical sensing [1] and Laser Induced Breakdown Spectroscopy (LIBS) [2].
Limited to stationary measurements.
Commercial.
1. Ben-Dor, E., Heller, D. and Chudnovsky, A., 2008. A Novel Method of Classifying Soil Profiles in the Field using Optical Means. Soil Science Society of America Journal 72:1113-1123.
2. Mosier-Boss P.A., Lieberman S.H., Theriault G.A., 2002. Field demonstrations of a direct push FO-LIBS Metal Sensor. Environ Sci Techno 36:3968-3976