| Muck & Slurry
Manage muck to improve efficiencies and cut costs
Organic manures have a huge potential to provide farmers with a cheap fertiliser that can help improve soil and cut
back on costs, but getting the application right is important.
o help farmers
make the most of
their slurry and
muck, a wide
range of industry
experts were on
hand at Grassland UK, along with
the latest equipment and
machinery to make the job as
efficient as possible.
Spreading manures should not
just be using up a by-product, but
about fully utilising a valuable
resource, says head of show, Alan
Lyons. “Nutrient levels vary
considerably, as do the application
technology and regulations, so
there’s more to this simple
practice than just spreading it on
the field. The key is to maximise
nutrient availability by applying
manure in optimum conditions,
and thereby reduce the need for
inorganic inputs.”
Matching manure applications
to the soil nutrient status is crucial,
advises John Williams at ADAS,
who will be speaking in the muck
demonstration area and seminars.
“Muck and slurry should be used
and treated as a fertiliser, rather
than a waste product to just empty
T
on fields. It does take investment
in kit and management to do it well
but it’s a wonderfully valuable
source of nutrients.”
Every 40t/ha of cattle farm yard
manure can be worth £220/ha in
NPK value, he explains.
The first thing is to understand
the nutrient content of the material.
“Manures have hugely variable
nutrient content and dry matter
levels - and cow slurry compared
to pig slurry will be very different
because of the different feed
intakes. The AHDB Nutrient
Management Guide has averages
for a number of organic manures
and these typical figures are a
good starting point,” says Mr
Williams “Taking samples is the
next step and it’s important to be
representative when doing this. Try
to homogenise the slurry in some
way and take a number of samples
to see how the content varies.”
Farmers then have to decide
where to apply the muck. “With a
typical application you will be
supplying more phosphate and
potash than the crop will need in
one year, so repeat applications
can lead to high levels,” he
32 | Farming Monthly | June 2018
explains. “Therefore soil testing
first can identify where best to put
the manure.”
Application rates should be
tailored to meet the crop’s nutrient
demands. “This is reasonably
straightforward for slurry as you’ll
know what the tanker holds and
the size of the field but it’s more
difficult with solid materials as the
bulk density and weight can vary -
and newer material will take up
more space than old.”
One way to approach
application rates is to use a
spreader which has weigh cells,
but alternatively a weigh bridge
can be used. “If you apply without
knowing the weight, then you can’t
know what the application rate is.”
Mr Williams also suggests
making sure slurry and muck are
spread as evenly as possible and
that solids are incorporated within
24 hours to minimise smells and
reduce nutrient losses. “Spring
applications are better for nitrogen
use efficiencies but you’ve got to
be careful not to damage the soil.
Also, the risk of run off and
contamination is higher – so it’s
important to get timings right. In
the autumn it’s typically drier and
applications are best done in
September or October for crops
that require autumn N, such as
grass or oilseed rape – otherwise
you risk leaching.”
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