Home' Grower : March 2012 Contents The South Australian Grower -- March 2012
Compost for vineyard renovation
latter show that there is more
than 1 or 2 deficient nutrients in
the leaf test.
For example high sodium and
chloride is usually associated
with calcium deficiency and
sometimes nitrogen deficiency.
Trace elements may also be
deficient and it is likely that
plant roots will be shutting
down. Diseased or physically
damaged roots will often result
in nutrient deficiencies in plant
tissue tests irrespective of soil
nutritional status, hence
regularly inspect root systems.
Frequent cultivation of soils
in annual vegetable cropping
systems can reduced organic
carbon to very low levels.
Without the organic 'cements'
the soil crumbs will not break
easily, reducing the effectiveness
of applying calcium.
It is extremely important to
also improve the organic
carbon content of the soil by
cover cropping and application
of compost to raise the number
of sites which can hold the
exchangeable cations for plant
uptake. It is 'what you don't
see that does the job'.
This requires allowing the
added organic carbon to break
down as it would in nature.
Plants and compost are broken
down by microbes with the
organic materials mixed in
through the action of worms and
other soil dwelling organisms.
This natural process can be
promoted by mowing or
spraying off the cover crop, and
breakdown of organic materials
and weakens the soil structure
by exposing fresh surfaces to
the microbes responsible for its
breakdown and oxygen that
they use in this process.
Over the longer term
cultivating the cover crop back
into the soil will not effectively
raise organic carbon levels.
Details: Anthony Fox, senior manage-
ment adviser Adelaide and Mount Lofy
Ranges NRMB, 08 8523 7718 or
By KAYLEE MAITLAND
DEEP ripping and mound-
ing are two common tech-
niques that growers can
use to renovate their soil in
Using compost in conjunction
with ripping and mounding can
provide significant benefits.
Compost can help to reduce
some of the negative side effects
of these techniques, whilst max-
imising their benefits.
Deep ripping is often used as a
means to increase vine root
growth by breaking up com-
pacted soil layers.
Often when ripping is under-
taken, soil moisture levels are
ideal at the depth of ripping but
the top soil can be too dry and
suffer damage. To help combat
this problem, compost can be
added on the rip line and incor-
porated by discing. Applying
compost at a rate of 5 tonnes a
hectare to 10t/ha on the rip line
will help your soil recover after
ripping. It is also recommended
that compost should be spread
evenly across the mid-row at
8t/ha and incorporated as
deeply as possible -- a cover crop
should be established immedi-
ately to further stabilise the soil.
A rapid decline in soil structure
is often seen after ripping has
taken place, and this can be due
to the re-welding of the soil
fragments that are produced
through ideal ripping (5-25mm
Re-welding can be prevented by
placing a physical barrier between
the fragments -- and here is where
compost can be of benefit.
Applying 5-20t/ha of compost
and mixing it in with the soil can
help you avoid re-welding of
your newly renovated soil.
This will ensure that your reno-
vation effort has not been wast-
ed and will last much longer!
It is important that the ripping
process is carried out correctly -
compost can't help your renova-
tion where ripping has produced
dust and/or fragments less than
7 millimetres in diameter.
With a smaller particle size,
there are many more contact
points between soil fragmentsand
more opportunities for re-weld-
ing than compost can alleviate.
Mounding is a technique used
to increase the volume of soil
suitable for vine root exploration.
In some cases, this can be
achieved using compost mulch
without the need for mounding.
Compost mulch protects the
soil surface and moderates fluc-
tuations in soil moisture and
temperature which increases the
amount of top soil that is suit-
able for vine growth.
The added benefit of reduced
soil strength that mulch pro-
vides also means that the depth
of the root zone is extended,
allowing for optimum growth of
fine vine roots.
Compost mulch may help you
achieve your goal of increasing
the soil volume for optimum
vine growth, without the costly
expense of mounding.
Increasing your soil volume
through deep ripping, to break
up compacted layers, and the
application of compost mulch
should be your first option.
Mounding soil increases the
surface area which is exposed to
the atmosphere and creates large
pores throughout the mound
and at the soil surface.
This results in increased evapo-
ration of soil moisture -- which is
not a good outcome.
Applying mulch to the mound-
ed surface reduces evaporation,
increases surface moisture con-
tent and cools the surface layers
during the growing season.
The mulch layer also prevents
the collapse of the large pores on
the mound surface and prevents
the formation of a surface crust.
The effect of compost mulch
on soil moisture is more pro-
nounced on mounded soils than
on a flat surface.
Compost can be incorporated
into the mounded soil for addi-
tional benefits. In cases where
60-100t/ha of compost (5pc
dry matter) was mixed with mound-
ed soil or soil where the A1and A2
horizons had been mixed - root
length was significantly higher than
when no compost had been incorpo-
Soil str ucture and stability of the
mounded soils with compost was sig-
nificantly better -- even after all signs of
visible organic matter were gone at
the end of the second season, the
mounded soil with compost had
remained friable throughout.
More research is needed to deter-
mine more commercially acceptable
application rates, but the signs are
promising that compost incorporation
in mounded soils can significantly
enhance your renovation operation.
Vines at Barossa Valley.
at ripping can prevent
your soil from
re-welding and make
your renovation last
Compost can increase
the volume of soil
available for root growth
-- mounding may not be
surface moisture and
prevent collapse of large
pores in soil by applying
mulch to mounds.
This stops the formation
of a surface crust and
saves you water!
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