PiCUS Tension

Plus 19% VAT
Delivery Time: ca. 2-3 workdays

The PiCUS Tension is a system installed underground or above ground at the location of your trees. It can accommodate up to six water tension sensors that measure soil water tension, allowing for conclusions about water availability for your plants. The sensors can be positioned freely, either across the area or, for instance, within the root ball at various heights.

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    Prevent dry stress in trees

    In addition to the water tension sensors, a soil moisture sensor can be connected to measure soil moisture, conductivity, and temperature. Combining data from both sensors generates watering recommendations that enable resource-efficient irrigation. This helps minimize the risk of over or under-watering. Additional parameters required include the size of the tree disc, soil’s available water holding capacity, and the depth of root penetration.

    Installation & Handling

    The PiCUS Tension sensors can be installed directly during the planting of young trees on-site or retrospectively on mature trees that are particularly vulnerable or worthy of preservation. If desired, the sensor elements can be inserted at various depths or positions around the tree. The central electronics can be mounted above ground, for example, on the planting support of a young tree, or buried. Using an earth auger and the IML installation aid, the sensors can be positioned accurately.

    Measurement variables

    Soil water tension refers to the force with which water is held in the pores of the soil, indicating the amount of force plants need to exert to access water. The lower the soil water tension, the more easily water is available to plants. Conversely, high soil water tension makes water less available to plants. In addition to soil water tension, the current temperature is also measured within the transmitting unit and depicted in the graph.

    The optionally mountable soil moisture sensor with a cable length of 3.2 meters measures soil moisture, soil conductivity, and soil temperature. With the corresponding soil parameters, the maximum water absorption capacity of the respective soil or granules can be determined.


    Depending on the application, the following components can be individually configured when ordering:There are LTE and LoRaWAN variants of the Tension system available.

    PiCUS Tension LTE 6 Inputs

    • Includes cloud and data connection
    • Very easy setup with pre-configured and pre-assembled units
    • Included SIM card with 500 MB is usable worldwide
    • Supports up to 6 suction tension sensors (pf) and 1 soil moisture sensor (rH in % and °C)
    • Selectable length of sensor cables
    • Android and iOS app support

    PiCUS Tension LoRaWAN 6 Inputs

    • Very easy setup with pre-configured and pre-assembled units
    • Supports up to 6 suction tension sensors (pf) and 1 soil moisture sensor (rH in % and °C)
    • Frequency Europe 863.870MHz
    • Selectable length of sensor cables

    *Please note that for a custom LoRaWAN network, currently no evaluation and interface software is offered; please inquire separately. There is the option to evaluate and filter data through the free “thethingsnetwork” and IML WebGIS! See LoRaWAN options.


    • Installation aid 120 cm
      Installation aid to place the sensors in the soil
    • Cable protection 50cm
      Metal protective hose as cable protection for above-ground installation, e.g., during mowing
    • Pointed probing rod 30cm
      Can be used as a probing rod in combination with the installation aid
    • Earth auger 30 mm x 1000 mm


    In the WebGIS, there’s the capability to filter data, export it in various formats for further external processing, and integrate it into external software solutions. Automatic forwarding from the IML Cloud to a client-owned database is possible, enabling data integration into existing infrastructures such as a cadastre database.

    IML GIS Reporting

    The measurement data can be filtered, for instance, by pF value, and this can generate a clear Excel file. This presents a clear view of which trees require watering.


    The IML APP is necessary for setting up the system and documenting water inputs, such as:

    • Tree parameters
    • Soil parameters
    • Number of sensors and sensor depth
    • System location (displayed in IML GIS)
    • Data query for current status, etc.

    IML Cloud

    With the LTE variant, sensor measurements are taken every hour, and the stored data is sent to the IML Cloud every 12 hours. This transmission interval allows for up to three years of operation without needing to replace batteries. The data stored on the server in Rostock is processed and visualized in IML GIS or the IML APP.

    LoRaWAN Options

    In a client-owned LoRaWAN network, such as in “smartcity,” the system is configured for data transfer to the client’s own data infrastructure. In this case, however, the client needs to process and visualize the data. Alternatively, if the client provides raw data to IML, it can be processed and visualized in IML WebGIS. This variant is customer-specific and needs to be requested accordingly.

    Forwarding data from a public LoRaWAN network, like “thethingsnetwork” (TTN), to PEC is possible to view the data in IML-WebGIS. This offers the advantage that the client can utilize the LoRaWAN variant without needing to develop, purchase, or set up their own visualization and evaluation software. However, the availability of a TTN network is required.

    Shared Comparative Database (optional)

    During setup, IML Cloud provides the function of making data available on a comparison platform for measurement values. Property owners can access data on comparable trees or sites through the database, providing references for their own evaluations and planning. Only data about the tree and installation situation are visible, never about the user or location. Participation in the comparative database is voluntary.


    The system is designed for continuous use for up to 3 years. The transmitter unit can be reused by replacing the battery. Since the Watermark soil tension sensors remain in the soil, they need replacement and expert reconnection to the transmitter unit.

    Scope of delivery

    Standard scope of delivery:

    • Central electronics
    • 1x Sensor
    • 3 years of Cloud support
    • PiCUS Environmental Cloud
    • PEC.Service app
    • Web-GIS

    Measuring principle

    Measuring principle:

    The relevant measurement result of the Tension is the soil water tension, expressed as a pF value. The soil water tension indicates the force with which the water is held in the pores of the soil, i.e. how much force plants have to exert to get to the water. The lower the soil water tension, the more easily the water is available to plants. If the soil water tension is high, the water is hardly available to plants. In general, a high water content of the soil tends to lead to low water tensions and a low water content to high water tensions and thus poorer water availability. However, the water content alone does not indicate whether the water can also be reached by the plants. Therefore, the Tension works with the soil water tension. This is comparable for all soil types and is a direct indicator of the situation of the plants. Classically, soil water tensions are given as (negative) pressure, in kilopascals or hectopascals. To avoid confusion due to different units, the system basically works with the pF value, which is the decadic logarithm of the water tension in hectopascals. It takes a value between 1 and 7. For a better overview, the pF values are additionally assigned to the colours of a traffic light scale.

    Values below 1.8 or above 4.2 are not to be expected. The classification is an approximation. Depending on the constellation of soil type and tree species it is principally possible that even at relatively low pF values drought stress occurs.