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HOW TO USE THE ROOT WASHER
HOW IT WORKS
The Delta-T Root Washer comprises 4 buckets modified with a central overflow
downpipe. Water from two jets at the base of each bucket swirls around and up,
teasing roots and soil apart. The lighter roots float up with the water flow, into
the central overflow pipe, and are then caught in a 550 micron mesh filter in a
funnel under the table.
The soluble fraction of the soil is washed through the filter. Gentle agitation by
the operator helps free up the soil. The remainder of the roots, stones and debris
remain in the bucket. Finally the water supply is turned off and the bucket
emptied through the filter, to catch remaining roots. The debris in the bucket then
dumped out and the cycle restarted.
The root washer has a four-tap controller, this allows the operator to adjust and
switch off the water supply to individual buckets where required.
Kirchhof & Pendar, with a similar design, found they could wash about 10
samples an hour, but this depends on soil type and sample volume.
STEP BY STEP
1.
Weigh.
Before washing roots you may wish to measure the mass and volume
of the whole soil sample and of each subsample.
2.
Pre-soak.
Some soils are strongly held together by electric charges. These
bonds can be by soaking the soil overnight in a bucket of water to which you
have added an ordinary domestic water softening agent.
3.
Turn on the water slowly
. Once connected to the mains water supply (or
optional pump) the water can be turned on. This is best done slowly to allow
for the removal of air in the pipework and minimal amounts of water spray.
Check all connections for leakage at this point and tighten where necessary.
Once the level of water has reached the nozzles in the buckets then the supply
can be turned fully open and root washing can commence.
4.
Adjust the flow rate:
For optimum performance the root washer requires a
water pressure of 50 to 70 psi and a flow rate of 10 gallons per minute. The
UK mains water pressure is about 40 psi, just a bit less than ideal but still
useable. If you are using the pump use the bypass tap to control the flow rate.
The water should swirl around the buckets creating a vortex which overflows
into the central tunnel.
5.
Place a soil sample in a bucket.
6.
Wait for the water pressure to break up the soil. The resulting vortex will lift
the lighter roots over the lip, down the central tunnel, and onto the mesh in the
funnel.
7.
Assist the more reluctant lumps to disperse by breaking them up with your
hands.
8.
Continue washing until the water is clear and all roots are clear of soil.
9.
Switch off the water to the bucket using the three-way hose switch provided.
