Techniques for avoiding poor installation – Campbell Scientific Sentek EasyAG Installation Guide v 3.0 User Manual

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Troubleshooting the preferred installation method

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Techniques for avoiding poor installation

Soil Suitability

EasyAG probes may be installed into a range of soil types ranging in texture from light sand
to heavy clay. It is unsuitable for installation in stony ground, where the average stone size is
greater than 10 mm. This is because large stones may damage the plastic cutting tip of the
probe and divert the direction of the insertion.

Problems may be encountered when installing EasyAG probes in dry soil. Hammering the
probe into dry soil can cause significant back pressure, which can create substantial vibration
of the tube and widening of the hole. In extreme situations, hammering the tube into hard, dry
soil may cause the dolly to break through the bottom of the access tube. It is recommended
that the whole moisture monitoring unit be well-watered to a depth of 1 metre prior to
installation. Squirting a small amount of water into the hole prior to installation of the probe
may also assi st if pre-watering is not possible.

Hammering Technique

Blows from the sledgehammer should be well directed straight down onto the beating head of
the AMS soil sampler with as little lateral (sideways) impact as possible. This minimizes the
chance of an air gap forming between the soil and the access tube. Any air gap will result in
preferential flow of water down the side of the access tube. This must be avoided.

Soil Sampler Extraction

When extracting the AMS soil sampler, care must be taken to ensure the integrity of the hole
is not compromised. The soil sampler must be pulled upward directly and smoothly.

Air Gap Correction

At every stage, it is important to avoid the formation of an air gap between the soil and the
access tube. In some very loose, recently mounded soils, the formation of small air gaps at
or near the surface is almost unavoidable. In these soils, small air gaps of 1-2 mm between
the soil and the access tube near the surface may be closed be pressing the soil against the
tube using light finger pressure, without causing major errors in soil moisture detection.

Air gaps of greater than 2 mm between the soil and the access tube at or near the surface in
these soils may be corrected by pushing the soil against the access tube. This can be done
by carefully pushing a spade into the soil adjacent to the probe and gently levering the soil
against the access tube.

Note: The spade should be at least 15 cm away from the access

tube when this is done to limit any errors in soil moisture detection.

Any grooves formed by the spade should also be filled in to avoid

the formation of areas of water accumulation.

This procedure should not be adopted as standard practice in all situations. Sufficient care
should be taken to avoid air gaps where possible, and reinstallation should be considered as
the first option if air gaps do occur. The above procedure is only recommended in those very
loose soils that have been recently formed into mounds, seed beds or similar, where the
development of air gaps is almost unavoidable.