Delmhorst Instrument KS-D1 - Manual (Page 11)

10
WHERE TO PLACE BLOCKS
The location and depth of the blocks depends on the nature
of the crops, the potential root zone, the type of soil and
subsurface formation, and the profile of the field. While
it is not possible to give specific instructions applicable
to all cases, there are some guidelines to be followed:
(A “string” of blocks 2, 3, or 4, depending on the depth
to be reached, is called “station”).
h Select a station locations where the plant population
is representative of the field. Do not place the blocks
in low or high spots or near changes in slope of the
irrigation run unless you wish to measure variability
in water penetration caused by such differences.
h Keep the soil around the stations from becoming
compacted when taking readings, especially where
blocks are planted near the surface. Do not walk in
furrows in which soil moisture readings are being
measured. Walk in the next furrow. Mark each
“walk” furrow when installing the blocks.
h When using sprinkler systems, make sure the blocks
are set so they will not be damaged when the sprinkler
is moved. Inaccurate readings can also result if the
blocks are placed too close to the sprinkler head.
h The blocks should not be shielded by any low hanging
branches or in an area that may be flooded by run-off.
In the case of row crops, the blocks should be located
directly in the row. In orchards, the blocks are located
at the drip line of a tree.
We recommend that a second string of a few blocks be
placed in the ground not far from the first – 10” to 20”
apart. This will serve as a control on the blocks and on
other factors. If the readings of two adjacent blocks at the
same depth show a significant discrepancy, the cause should
be determined. It may be poor distribution of water from
the sprinkler system, or difference in sprinkler distribution
caused by wind, differences in root concentration surrounding
the block installations, or differences in the soil.
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