LoRa Agriculture Sensor User Guide
T0005978_UG
Version # 1.9
TEKTELIC Communications Inc.
Confidential
Page 7 of 22
is an electrical conductor thereby providing a relative indication of the soil moisture
status. As the soil dries, water is removed from the sensor and the resistance
measurement increases. Conversely, when the soil is rewetted, the resistance lowers.
The relationship of ohms of resistance to centibars (cb) or kilopascals (kPa) of soil water
tension is constant. The Watermark is calibrated to report soil water tension or matric
potential, which is the best reference of how readily available soil water is to a plant.
The raw data reported by the sensor for the watermarks is a frequency that increases as
the watermark gets more saturated. Please refer to the TRM for information on how to
convert the frequency to Soil Water Tension.
It should be noted that Watermark sensors need to be installed wet. If time permits,
slowly wet the sensor by partially submerging (no more than half way) for 30 minutes
in the morning and let dry until evening, wet for 30 minutes, let dry overnight, wet
again for 30 minutes the next morning and let dry until evening. Soak over the next
night and install WET. This will improve the sensor response.
There are several things to note regarding installation depending on the use case for
the Watermark sensor. Please review “Sensor Installation” on Page 1 in the file “701
Meter Manual-WEB.pdf” file in the User Guide section of Agriculture Sensor in the
Knowledge Base of the Tektelic Support Portal.
Soil Surface Mount Probe: Option to measure soil moisture content and temperature.
The probes work in a similar manner to the Watermark Sensor described above. There
is no exchange of water with the surrounding soil, however. The probes simply measure
how saturated and warm or cold the soil is that they are inserted into. The raw data
provided by the sensor for soil moisture is a frequency. Please refer to the TRM for
information on how to convert the frequency to Gravimetric Water Content.
Figure 1 illustrates the Agriculture Sensor Soil Surface Mount Model in the enclosure.
a)
Exterior view
b)
Inside view
Figure 1 Agriculture Sensor Soil Surface Mount Model
