• Soil Moisture Monitoring package reviews about 25 products presenting pros and cons. (Several large pdf documents, but well worth reading). Details are also given on how to obtain hard copies of the publication.

• Soil Water Monitoring and Measurement a very useful comparison of common methods from the end-user point of view. A well written, long document in html format, and still relevant even though conducted in 1992.

• Comparison of TRIME-TDR (time domain) and capacitive (frequency domain) moisture measuring systems courtesy of IMKO

• In a report entitled "Soil Water Sensor Performance" submitted to Applied Engineering in Agriculture in June of 1997; reviewed and approved for publication by the Soil & Water Div. of ASAE (American Society of Agricultural Engineers) in November 1997, Vol. 14(2):121-133. The authors are Ronald E. Yoder, John B. Wilkerson, Daniel C. Yoder, and David L. Johnson. The report compares eight different soil moisture sensors. Included are Automata's Aqua-Tel sensor which was reported as the best when accuracy, reliability, durability, and installation factors were considered.

• In a presentation at the 1999 ASAE/CSAE-SCGR Annual International Meeting, entitled "Laboratory Evaluation of Soil Moisture Sensors" by S. Proulx, R. Sri Ranjan, and G. Klassen, Automata's Aqua-Tel sensor along with four other soil moisture probes, were evaluated. Paper No. 992169. For more information, contact ASAE, 2950 Niles Rd., St. Joseph, MI 49085-9659, USA.

• "Evaluations Of Dielectric Soil Moisture Sensors For Irrigation Scheduling" was presented as Topic 3 at: the International Symposium on Irrigation of Horticultural Crops, Estoril., Portugal 1999 by Hanson, B.; Douglas, P. and Serrarens, D.
  A more readable update to this research presented on the Irrigation Journal pages makes interesting reading.

• "Time To Compare Soil Moisture Sensors" compares some of the sensors that measure the capacitance/dielectric constant of the soil. These include EnviroScan, Troxler Sentry, AquaTel and AquaFlex. It was published in the newsletter:

        The Washington Irrigator Newsletter,    Vol 3, Issue No.3
            A WSU Cooperative Extension - Prosser Publication February 1999
        Author:
            Brian Leib Phd,
            Extension Irrigation Specialist, Washington State University,
            Irrigated Ag. Research and Extension Center,
            24106 North Bunn Road, Prosser WA

• Laurent J.P. "Profiling water content in soils by TDR : experimental comparison with the neutron probe technique", invited Lecture at the Consultants' meeting, AIEA, Vienna, 23-25 Nov. 1998, to be published, AIEA, Ed. (PDF)
• Comparisons of soil-water measurements using TDR and other techniques in KwaZulu Natal, South Africa Earle Ripley, Michael Savage, Gastão Lukangu, Colin Everson. 1998

• A laboratory comparison of some currently available soil moisture monitoring devices - J P Tyndale-Biscoe and H Malano. Agricultural Engineering Australia, Vol 22 Nos 1 & 2 (1993).

• Neutron probe shootout (pdf document) "..compared Troxler and CPN neutron probes with the Troxler capacitance probe (Sentry 200).."

• Perry, Eileen M. Carlson, Toby N. Comparison of Active Microwave Soil Water Content With Infrared Surface Temperatures and Surface Moisture Availability. (Paper 88WR03047) Water resources research. OCT 01 1988 v 24 n 10 Page:1818

• Schofield, T. G., G. J. Langhorst, G. Trujillo, K. V. Bostick, and W. R. Hansen. 1994. Comparison of Neutron Probe and Time Domain Reflectometry Techniques of Soil Moisture Analysis. Proceedings of the Symposium on Time Domain Reflectometry in Environmental, Infrastructure, and Mining Applications, Evanston, Illinois, Sept 7-9, U.S. Bureau of Mines, Special Publication SP 19-94, NTIS PB95-105789, pp. 130-142

• Dasberg, S. and F.N. Dalton. 1985. Time Domain Reflectometry Field Measurements of Soil Water Content and Electrical Conductivity. Soil Sci. Soc. Am. J., Vol. 49, pp. 293-297.

• See the favourable findings of independant comparisons of
  the Streats Aquaflex against other sensor types at Cambridge University!

• An update of the earlier Blaine Hanson research on comparisons of the following soil moisture sensors: tensiometers, Watermark resistance blocks, and gypsum blocks and the dielectric instruments Sentry 200-AP, TRIME, TRASE, Enviroscan, Aquaterr Moisture Meter, and DeltaT ThetaProbe. The general findings of which types are easier to install and or use are briefly presented. http://www.greenindustry.com/ij/1999/0499/499soil.asp

• Case study of data from two capacitance sensors (EnviroSCAN and C-Probe) versus Plant water requirements as calculated from evaporation data in an avocado orchard. http://ats.com.au/~hortech/comparison.html

• AFP219 Evaluation of soil moisture sensors finds that not all sensors perform equally... S. Proulx, R. Sri Ranjan and G. Klassen. Department of Biosystems Engineering, University of Manitoba, Winnipeg, MB. R3T 5V6

• Soil moisture sensors for sandy soils Agriculture Western Australia Farmnote from 1994: Nine types of sensor are evaluated for use with irrigated horticultural crops on sandy soils.

• ThetaProbe comes out on top again! (The Potato Research Group at the University of Mannitoba this time.)

• A comparison of the CS615 vs Watermark sensor is one diagram from paper on mudslide movement by the U.S. Department of the Interior U.S. Geological Survey.

• Gypsum block vs Nmm vs TDR

Relevant Links

Campbell Scientific supports Sowacs

Data Logging Application and Measurement Systems Engineers


Soil Moisture Meter



Remote data acquisition and control systems


PRISM - CMP by Irrigation Scheduling Methods, Inc.

Research, Products, Consultancy on Real-Time Water Dynamics