SOI (Spot On Irrigation) – A Zero-Maintenance Tensiometer

Imagine it’s the middle of summer and you are driving by your fields, orchards, or research plots. The crops look healthy, but you wonder about the moisture levels in the soil for the upcoming days. Which block or field should you prioritize for irrigation?  Additionally, you may be concerned about the previous irrigation event and saturation levels of soil.

SoilMoisture’s SOI (Spot On Irrigation), is a zero-maintenance tensiometer connected to a high visibility display that can be easily seen from a distance for an immediate insight of the soil moisture levels. You can make onsite irrigation decisions without the need for a sophisticated soil monitoring system!

The SOI display is very intuitive. It consists of 7 vertically aligned coin-shaped indicators. Each coin has a black and a bright yellow side. Once the soil is fully irrigated, all 7 coins flip yellow. A column of 7 yellow indicators (coins) means that the soil has high levels of moisture (perhaps even saturated). As the soil dries out, the coins flip black one by one and from the top coin to the very bottom one. Therefore, one can always tell the moisture status of the soil by considering how many coins are yellow. A display that shows one or no yellow coins indicates very dry soil. Since the coins are visible from several feet away, you do not even need to walk to the display to read them.

For each type of crop or tree, a certain number of yellow coins indicate the proper level of soil moisture.

The SOI installation is simple. Everything you need is included in one package except for a ¾” PVC pipe, which will be sourced locally and cut to match the depth of the installation (active root zone). No training or calibration is required. The high-contrast yellow and black colors were selected so you have no trouble drawing conclusions about the soil moisture status. The SOI package is compact, making it easy to store on shelves and use as needed.

For optimal results, we recommend using one SOI per acre of crops near a tree or plant. If you suspect that there may be variations in soil types and moisture conditions, more than one may be needed. However, if the soil is more uniform, fewer SOIs may be necessary.

SOI can be installed at the beginning, at the middle, and the end of the rows and at the target depth of irrigation. This way by simply looking at the SOI displays from a distance you would be able to tell exactly when the wetting front hits the target depth (all the coins turn yellow). This is a very simple, intuitive, and yet powerful method for optimizing irrigation practices.

SOI can also be installed at different depths. For example, for big trees you might decide to install an SOI at 4 feet or even deeper; or install two SOI units, one at 2 ft and one at 4 ft. While, for a row crop the desired installation depth might be only a few inches. Ultimately, we trust you to make the best judgment for your specific circumstances.

Call us at (805) 964-3525 for more information about SOI.