Are GroPoint soil probes compatible with all data loggers?
GroPoint Profile and GroPoint Pro will work with virtually any data logger that supports the SDI-12 standard.
GroPoint Lite and Classic will work with virtually any data logger. Just ensure your data logger will handle the output of your GroPoint Lite sensor (whether analog or digital).
Can a GroPoint soil probe be used as a portable solution?
No, GroPoint soil probes are meant to be used on a permanent or semi-permanent basis. There should be minimal disturbance of the surrounding soil for proper accuracy.
What kind of soils can GroPoint soil probes be used in?
GroPoint soil probes can be used in virtually any soil.
Can the sensor cable be buried, and is it durable enough to be left exposed on the surface of the ground?
GroPoint soil probes are furnished with a high quality cable suitable for direct burial or exposure to direct sunlight. It is resistant to damage from insects, abrasion and normal environmental exposure. However, mechanical damage from hoes, coyotes, gophers, other animals, and cultivators can easily cut this cable. Any problem with this sensor will most likely be due to damage to the electrical cable. To prevent damage, it is strongly recommended that the cable be installed in 3/4-inch electrical conduit. This size conduit is required to accommodate the passage of the plug connector.
What is the maximum length of cable that can be used with the sensor?
For SDI-12 sensors, according to the SDI-12 specification, the combined length of all sensors connected to a data logger cannot exceed 610 m (2,000 feet). So one sensor with a 610 m cable or 10 sensors each with a 61 m cable.
For analog sensors, the maximum length is 305 m (1,000 feet).
It should be noted that the longer the cable is, the more susceptible the sensor is to catastrophic damage/failure due to increased voltage spikes from lightning strikes. A long cable becomes a very large antenna to amplify the voltage. Cable should be buried wherever possible.
The minimum wire gauge when using a cable approaching the maximum should be 20 AWG.
Can I use my own cable to extend the length of the standard cable?
Custom cable lengths can be ordered from us, or cable may be spliced by the customer. Each cable has three wires. The cable must be 22 gauge copper or larger.
All connections should be made inside a waterproof box using silicone filled, waterproof, wire nut connectors. These waterproof connectors are available at local electrical/hardware suppliers, such as The Home Depot.
Why is it so accurate? Most soil sensors I see are only accurate to 3%.
GroPoint soil moisture sensors feature an accuracy rating of ±2% (±0.02 m3m3) volumetric water content in the soil, between the range of 8% to 42% VMC (this is the normal range for agricultural applications). We obtain this accuracy through a patented technique which improves the performance of the already reliable TDT method of soil moisture measurement. This patented technology is called TDT5.
While a < ±1% accuracy rating is achieved in controlled laboratory conditions, GroPoint soil moisture sensors are factory calibrated for most agricultural soils. In field applications, accuracy may slightly decrease due to the inevitable heterogeneity of soil texture, soil compaction, moisture and fluctuation in soil temperature. The accuracy may also decrease in difficult soil conditions (higher clay and salinity content). For these reasons we state a real-world accuracy of ±2%. In normal conditions, GroPoint soil moisture sensors will maintain this accuracy from permanent wilting through field capacity in sandy loam through clay soils with less than 60% clay particles. Under moderately saline conditions, GroPoint sensors will maintain their accuracy up to 6 ds/m.
What is the area of influence, or measurement volume, for the Gro Point Classic?
The GroPoint Classic sensing element will measure the differences in soil moisture up to 10 cm (about 4″) from the rods along all sides. A typical GroPoint measurement will interrogate an oval shaped area approximately 15 cm (6″) high x 23 cm (9″) wide x 37 cm (15″) long. The soil closely surrounding the rods will have a greater influence on the soil moisture reading than the soil about 8 cm (3″) away from the rods. The soil must be in direct contact with the rods to ensure an accurate reading.
Do I install my Gro Point Classic vertically or horizontally?
GroPoint Classic sensors can be installed vertically or horizontally. Horizontal is the preferred method for a shallow sensing area and vertical for sensing deeper than 30cm (12″). With a horizontal orientation, soil can be more easily packed around the elements, and this method also gives a more precise measurement of soil moisture in a specific range. In horizontal installation, the sensor will be measuring the soil moisture in an area about 7 cm (3″) above and below the sensor.
With vertical placement, the sensor will report average soil moisture over it’s entire active length of 40 cm (16″). This may be the desired orientation for covering the majority of the root zone of a crop with one sensor.
Caution: With this large active length, soil at the top could be dry and the bottom wet, resulting in a reading of good average soil moisture. With the roots concentrated in the dry topsoil, the crop could be unnecessarily stressed. Use the suggested vertical installation only when the crop roots have grown to cover the entire length of the sensor.
Obtaining good soil compaction around the sensor is more difficult with a vertical installation. Make sure that there are no air pockets around the sensor elements when back filling the hole.
I’m not in BC or Canada. Can I buy and obtain support for GroPoint products locally?
GroPoint has dealers in several international locations. You can find your local dealer on the Dealers Page
GroPoint products are also sold online and we offer several self-help support resources, as well as unlimited support via phone, email and online chat.
