Soil Tension and Irrigation Event Reporting Gives a Precise Look at Water Management

By Brian Hanson
Hortau Grower Support Specialist

Since 2002, Hortau has led the industry in innovating irrigation management. From designing and patenting the only real-time reporting soil tension sensor, to pioneering connections with cellular networks, Hortau has paved the way.

Since the company’s inception there have been many advances in equipment such as the introduction of solar-powered stations (versus battery-powered units), and the addition of cellular modems (versus line of site and radio frequency), both of which allow for standalone stations that can report field data in real-time.

Hortau also introduced extra equipment to help growers better understand what else is happening in the field by leveraging data from temperature/humidity sensors, and pressure switch sensors. Through all of these innovations, Hortau’s soil tension sensor remains the driving force in determining plant stress, but the addition of the pressure switch makes measuring irrigation management that much simpler.

The pressure switch is connected in-line with the drip hose (Fanjet) or sprinkler, and lets the grower know the exact time and date an irrigation begins and ends.

To show an irrigation event on our software graphs, the irrigation is displayed behind the soil tension sensor data to make it easy to correlate run times and frequencies with crop stress tracking. Displaying irrigation events on the soil tension graphs also let users know how long it took for each sensor —and that particular crop — to react to an irrigation event so that we can proactively adjust irrigations and anticipate when high/low tension points are met. With the combination of the pressure switch and tension sensors at different depths, growers can truly become precise in managing their irrigations and plant stress.

… using soil tension combined with irrigation event reporting, we are able to get a transparent look at our water management programs like never before.

Before pressure switches were implemented, growers/irrigators would set a run time based on educated guesses or previous history. But using soil tension combined with irrigation event reporting, we are able to get a transparent look at our water management programs like never before. More importantly, we see how the crop stress reacts to water at 2-3 key depths within the active root zone.

As plant demand increases, so does its water needs. In the image below, you can see that an Almond grower had adequate soil tension throughout 3 feet of the soil profile all the way through to the middle of April.

But from May 1 and forward, irrigations were only reaching 18 inches, and the tension at 24 and 36 inches was extremely high creating stress for the plants.

This was a crucial time for these almond trees, as you want to minimize water stress as little as possible from nut fill all the way to hull split. The grower obviously needed to run longer irrigations to get water deeper and meet the need of these trees during this critical time. Monitoring more precisely and seeing the pressure switch run times would’ve helped him understand this and his crop would have been much healthier.

(Downward spikes on graph near 6/1/2014 and after signify the emptying of sensors due to extended stress, and then being refilled again.)

After explaining why this occurred and how to prevent it, the grower was considerably better the following year (2015), but still not ideal. At critical times we were still seeing considerable stress in his tress even with our recommendations of longer and frequent irrigations. After another mediocre year, the grower was convinced that he needed a pressure switch to help correlate graphs and readjust his run times and frequencies.

Below is the same field, and same graph in 2016, but with a pressure switch. As you can see, he managed his irrigations almost perfectly.

The grower was able to adjust how often and how long to irrigate based on soil tension and the durations of previous irrigations. There was no stress at all from 2 to 3 feet, with very little at 18 inches.

Tension began to rise in June, but never became critical. They were then able to run a very long irrigation set to return tension to normal. It’s easy to see this grower did significantly better last year with the combined help of grower support, soil tension, and the pressure switch.


Grower Support specialist Brian Hanson was born and raised in Bakersfield and currently resides in Shafter, Calif. He followed a passion for ag to Bakersfield College, and then CSU Chico, where he studied Animal Science. Throughout college he worked with a PCA, and completed an internship focused on hay and cattle production.

After college, he began working as a Field Technician for Hortau installing and maintaining equipment in the field throughout Kern County. As a Grower Support specialist, Brian is committed to ensuring that all aspects of the Hortau platform are supported and he is always available to resolve any needs.

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