Odyssey
®
Xtreem
Single Soil Moisture Logger
User Manual
In the calibration tab select the soil type as Soil Test for all levels and press the submit button. We
suggest the logging interval is set to 1 minute for this test.
Place a 250mm diameter cylinder ( a 20 litre bucket with the bottom cut out ) around the logger and
fill with water. The water will slowly empty from the bucket into the soil. This may have to be repeated
several times depending on the soil type and the depth of the bottom sensor.
Using the Xpert portal select the chart page for this logger. It can be clearly seen that the moisture
value increases soon after the water is applied around the logger. The moisture value should rise to a
peak value then drop back a small amount and level out. The measured field capacity from the chart
page must be multiplied by 100 when entering it into the 'Field Cap' box on the Calibration page.
Find a soil type on the Calibration page where the field capacity is similar to the measured field
capacity ( x 100 ) and the drypoint value for this soil type should be the drypoint needed. Note the
values entered on this calibration page do not affect the factory calibration of the logger, just the
displayed and exported data. Choose the Custom Soil type from the drop down box and enter the
drypoint value and field capacity value.
Volumetric Measurement
There are three more parameters required for Xpert to calculate the parameters to give volumetric
soil moisture percentage.
These measurements are normally carried out by a qualified technician following a test Standard like
ASTM D2216 there the following is only an overview to aid in the understanding of the process.
Using a soil corer collect a saturated soil sample and place this sample into a plastic bag. The
volume of soil the corer collects is the
Saturated Volume
.
Accurately weigh the soil sample, this is the
Saturated Soil weight
.
Dry the soil, this is normally done in an oven over several days.
Accurately weigh the dry soil, this is the
Dry Soil weight.
Calculations
For either Percentage of Saturation or Volumetric Percentage the calculation is the same.
The slope and offset parameters are used as follows to calculate soil moisture.
Soil Moisture (%) =
((
Logger Reading
(
%
)
100
×
Slope
)+
Offset
)×
100
For a logger reading of 60.00% with calculated scale of 1.4815 and an offset of -0.3704.
((
60.00
100
×
1.4815
)−
0.3704
)×
100
= 51.85%
DATAFLOW SYSTEMS LTD
Page 6
V 03/21
