these Open Championship Clubs choose to relief grind - Pitchcare

particle will determine how the sand
performs in different situations.
The second information source relates
to percolation rates, i.e. how fast water
drains through the sand. This is done by
first saturating the sample - the amount
of water that enters the sand during a
predetermined period (usually an hour)
is called the infiltration rate. Different
sand types will have different infiltration
rates, which are determined by their
texture and structure. This, in turn, will
affect how quickly water percolates
through the sand, which is measured in
inches or millimetres per hour.
Since dry materials absorb water more
quickly than wet ones, the infiltration
rate is measured after the soil has been
saturated. The percolation rate for a
sandy soil is approximately 30mm per
hour.
The third crucial test is assessing the
relative pH value of the sand. This is a
measure of acidity and alkalinity using a
scale from one to fourteen; where seven
is neutral; less than seven is acidic, and
greater than seven is alkaline. It is
worthwhile pointing out that pH is a
logarithmic scale, so the difference
between a pH of 7 and a pH of 6 is 10
times the acidity, between 7 and 5 is a
100 times the acidity and, between 7 and
4, is a 1,000 times the acidity. This
clearly has an influence on how grasses
will grow and, as such, is a key indicator
to consider.
Armed with a proper assessment of
your own sand, it is now time to source a
non-native sand that will complement
and/or improve the conditioning of your
turf. As ever, this may not be as
straightforward as it first sounds.
There are many different types of sand
available, each with different
characteristics, and each performing a
different function. But, as we have found
out, the science of sand is carried out at
an almost microscopic level, where the
geography of individual particles
determines the qualities of the products.
With this in mind, there are three main
areas for consideration - particle size,
particle shape and particle colour.
Let us begin with particle size. In the
world of sand, particle size has a huge
impact on the draining characteristics of
your turf. The larger the particle size,
the more free draining the sand will be.
In many circumstances, the apparent
choice would be to opt for a sand with
the largest particle size but, sadly, this
could be a costly mistake. Firstly, particles
that are over 1mm in diameter can be an
aesthetic nuisance showing up on the
surface of a green. More concerning is
the fact that particles at this size can also
cause damage to mowers during cutting,
which leads to the prospect of kit being
out of use and the likelihood of hefty
repair bills.
Going large is perhaps not the best
option. Unfortunately, going small can
be equally devastating. If we take a
typical concrete sand, we will find a
medium containing plenty of coarse
particles, but also a fair proportion of
Technical
fine particles at the silt/clay level. These
finer particles can often bond together
causing a capping affect which prevents
water draining properly.
This problem is prevalent in golf
courses when clubs use their own sand
excavated from an on-site quarry. Whilst
the particle size may be perfectly
suitable, the natural silty/clay fraction can
affect drainage. An example of this
would be a bunker that has drained
perfectly well for a number of years, then
suddenly starts to puddle. Worse still if
this happens on the fairways or greens.
An ideal compromise is a single-sized
sand, with virtually nothing in the very
fine category. This will allow the sand to
drain consistently and is an ideal
candidate for sites where drainage is an
issue, for instance, inland golf courses.
But, of course, it doesn’t all come
down to size. The shape of the sand
particles can also play a part in drainage.
Brown sand, for instance, is wind blown
from the sea or riverbeds and, as a result,
has a rounded particle shape. This
profile means there is always route ways
between the particles, no matter how
tightly they are squeezed together
(imagine a large basket full of footballs).
These canals make brown sand ideal for
applications where drainage is
important.
Whilst brown sand benefits from a
secure network of arteries, white sand
particles are angular in shape and
naturally bed together like a stack of
triangles. Closer knit, the pointed shape
of these particles means white sand does
not drain as freely as a round-grained
sand. Moreover, because white sand is
formed by crushing sandstone rock,
which is soft in nature, the particles are
often held together with clay, which
needs to be removed through a series of
intense washing cycles.
The material differences between
brown and white sand have an obvious
influence over drainage, but the physical
inconsistencies don’t stop there. More
obvious than discrepancies in particle
shape is the clear mismatch in colour,
“Armed with a proper
assessment of your own
sand, it is now time to
source a non-native sand
that will complement
and/or improve the
conditioning of your turf”
FEBRUARY/MARCH 2012 PC 113