The IRROMETER Company has been in business since 1951, manufacturing soil moisture measuring, controlling, and sampling instruments used worldwide for scheduling irrigation. Principal brand names are IRROMETER (Tensiometer) and WATERMARK (electrical resistance granular matrix sensor).

These soil water potential/tension measuring instruments originated in the early part of the 20th Century, and were used by soil and plant scientists to measure soil water status in their experiments. In research applications, the use of these instruments allows the investigator to carefully manage the soil water status so as to eliminate soil water as a variable in the final result-irrespective of the purpose of the investigation (soil water status, nutrition, pest or disease incidence, etc.).

Although this technology is scientific instrumentation, the instruments are inexpensive and easy to use by farmers that irrigate. In production agriculture, the use of soil moisture based irrigation scheduling, provides a farmer with site-specific measurements of soil water status in the specific field, specific soils, specific irrigation method, and specific crop, as well as the site-specific microclimate.

The proper use of this information can lead to an irrigation scheduling management program which usually results in greater production, better quality, less water, energy and fertilizer use, and helps protect water quality by eliminating run off and deep percolation loss of water due to over irrigation. Most users of this technology have the initial cost of the instrumentation returned to them in the first season of use.

The use of soil moisture based irrigation scheduling has been proven an efficient way to deliver irrigation water for agriculture, nursery/greenhouse and landscape/urban irrigation. Further, the instrumentation can be used for controlling (automatic irrigation systems) and signaling (for data logging systems and inputs to weather stations).