The Irrometer tensiometer is the standard in accurate soil moisture measurement, offering growers an inexpensive and reliable means of measuring soil moisture for irrigation scheduling.  An Irrometer will measure the actual soil water tension, which indicates the effort required by root systems to extract water from the soil.  Because the Irrometer is a true measurement of soil water potential, the instrument is not affected by salinity and does not require site calibration.

The Model "R" is the standard one-piece Irrometer for general use with row, tree, and field crops.  Includes reservoir, air free gauge chamber, and hermetically sealed Irrometer vacuum gauge with dual scale of Centibars and kilopascals (0- 100 CB range).

Model R Brochure (.pdf)

 
The Model "SR" has a threaded replaceable tip as well as all the features of the Model “R” above.

Model SR Brochure (.pdf)

 
The Model "RA" is the Model “R” with direct switching capabilities.  Adjustable Moisture level selector switch may be set at any desired moisture level.  The switch will be closed past the setting to actuate the solenoid, time clock, or warning light.  Switch available for AC or DC power, please specify when ordering.

Model RA Brochure (.pdf)

The Model "LT" or “Low Tension” Irrometer incorporates a replaceable “Quick-Flo” tip, and a sealed vacuum gauge which has a full scale of 0-40 cbar.  Designed for situations where tensions above 30 cbar are rarely expected.  Ideal for very coarse solids, or container-media (non-soil), which can be relatively dry at 10-15 cbar or where rapidly changing soil water content needs to be observed.

Model LT Brochure (.pdf)

 
The Model "MLT", or Miniature LT, is considerably smaller in size than a regular Irrometer.  It is specifically designed for the smaller containers used in the greenhouse market.

Model MLT Brochure (.pdf)

 
The Model “TG” is for turf areas where underground installation requiring horizontal placement is desirable.

 
The Model “TGA” has all the features of the Model “TG” but with automatic switching capability.

Standard lengths are 6", 12", 18", 24", 36", or 48" dependent on the rooting depth of the specific crop.  Longer lengths are available by request.

Irrometer models are also available with Remote Sensing Unit (RSU) 4-20 ma transducers for use with electronic data logging equipment, including our Watermark Monitor.  The RSU can be installed in the gauge port of any standard Irrometer and the MLT, thus converting the reading to a 4-20 mA loop current signal.  It can be interfaced with a 4-20 mA loop current terminal or to an A/D card designed to read voltage.  Excitation current requires 9-24 VDC. Available in three calibrations:

0-93 cb for use with Model R, SR, or TG

0-32 cb for use with Model LT or MLT

0-16 cb for use with Model LT or MLT

The Watermark sensor (granular matrix sensor) is an indirect, calibrated method of measuring soil water. It is an electrical resistance type sensor, read by data logging equipment or a Soil Moisture Meter (pictured below, center) which converts the electrical resistance reading to a calibrated reading of Centibars (or kPa) of soil water tension.

Introduced in 1979, patented in 1985, and manufactured by the Irrometer Company since 1989, this irrigation sensor has been a major break-through in soil moisture measurement technology. It has been the subject of scientific investigation by plant and soil science since the mid-1980's, and has demonstrated itself to be an affordable and practical substitute for tensiometric measurement in most agricultural and landscape irrigation environments.

The Watermark sensor is an ideal solution for both agricultural and landscape applications.  Its electrical characteristics make it ideally suited for use with electronic data logging equipment.  We also offer a simple and practical handheld digital meter (30-KTCD-NL) for manually reading Watermark sensors installed in the field.