The new CSIRO
FullStop device does two things:
1. A FullStop detects whether the soil is wetted down to
the depth at which the FullStop is installed
The FullStop Wetting Front Detector is a specially shaped funnel, a
filter, a float and a flag. The funnel is buried
in the soil, at a depth in or below the active root zone of
the plants. When rain falls or the soil is irrigated, water moves downwards
through the soil. A wetting front is the boundary between the wet and the dry
soil. The water moves as thin films around the soil particles. As the wetting
front moves down into the buried funnel, the cross sectional area of the funnel
narrows and the water in the films is contained in a shrinking volume of soil.
This causes the soil at the bottom of the funnel to get wetter and wetter. The
soil becomes so wet that water seeps out of it and passes through the filter to
be collected in the reservoir. This water floats a light-weight rod which in
turn operates a flag above the soil surface that indicates that the soil is
"full" so irrigation should "stop", hence the name "FullStop". 
The FullStop has no wires, no electronics and no batteries.
Water from a wetting front converges in the funnel to fill the reservoir and
this raises the float. If the soil is dry before irrigation, the dry soil
absorbs more water and the wetting front penetrates the soil only to a shallow
depth. However if the soil is wet before an irrigation, it cannot store much
more water, so the wetting front penetrates the soil to a deeper level.
2. A FullStop collects a water sample that can be used to
measure the amount of salt in the rootzone
A syringe is used to extract the water-sample from the
FullStop, via the 6 millimetre (mm) tube. The salinity of the water sample
can be measured using an electrical conductivity meter.
Further Reading:
The Fullstop
Experience at Angas Bremer: 2008 Report on Salt monitoring at Angas Bremer 
(2.69
Mb)
FullStop at Angas Bremer: A report on the
2002-3 data to the Angas Bremer Water Management Committee
Inc. 
(196 Kb)
FullStop Record Sheet
(9Kb)
(33Kb)
Full District Report 2004-05 
Brief Report for 2004-05
