Home' Grower : September 2012 Contents The South Australian Grower -- September 2012
Study cuts into carrot powdery mildew
POOR farm hygiene practices could
be contributing to the spread of
powdery mildew in carrots.
National Vegetable Levy-funded
research has revealed the disease
can be carried from one crop to
another through the clothes of field
workers or machinery.
The results come out of project
VG08044 Investigations and
Developing Integrated Management
Strategies for Carrot Powdery
The major findings showed the
disease can transfer from an infected
crop to a healthy crop through field
workers' clothing or machinery and
could be controlled by using
fungicide and minimised through the
use of overhead irrigation compared
to drip irrigation systems.
The research also showed that
powdery mildew of carrots was
more prevalent in temperate
conditions through spring and
autumn, and that growers should
actively choose a seed variety which
had a high resistance to the disease,
such as the Stefano carrot variety.
The research was completed by
Andrew Watson, project leader from
the NSW Department of Primary
Industries, with the assistance of Dr
Hoong Pung of Peracto in Tasmania;
Barbara Hall of the South Australian
Research and Development
Institute, and Dominic Cavallaro
from Cardinal Horticultural Services.
The project was funded by
Horticulture Australia Limited using
the vegetable levy and matched
funds from the Federal Government.
Sweet fruits of labour for Comboyne farmers
By KAYLEE MAITLAND
THE rolling green hills of the
Comboyne Plateau have
highly fertile volcanic soils.
With an annual rainfall of about
2000 millimetres, Comboyne was
originally a prime dairy farming
region but recent years have seen a
growth in horticultural production
with plantings of avocados,
blueberries, macadamias and a range
of other fruits and vegetables.
The Tideman family has been
growing blueberries and avocados in
the Comboyne region since 2005.
Their four hectares of blueberries
and 60ha of avocados are grown
with minimal chemical inputs.
Sustainable farming is fostered
through a focus on biologically
friendly practices for their plants and
"Composted mulch has improved
our drainage and reduced our weed
cover," said Penny Tideman.
Weeds, especially kikuyu, have
always been a big problem for the
Tidemans. At one stage, they
employed two people full-time just
to weed the blocks.
The Tidemans tried a range of
mulching methods to reduce weeds,
including permeable weed mat and a
combination of wood chips and
They also had areas on their farm
with poor drainage. Avocado trees in
those areas were prone to
waterlogging and infection from
fungal disease Phytophthora,
which kills trees.
After attending a Soil
Foodweb Institute workshop in
2005, the Tidemans decided to
make their own composted
mulch and compost tea on-site.
They wanted to see if
composted mulch could reduce
weeds and improve the soil's
health and structure, and were
happy to find out that it did.
Art of producing rich soil
Each year, Comboyne farmers
Ernst and Penny Tideman mix
hard wood chips and poultry
manure with several tonnes of
avocado and blueberr y prunings
from the farm.
A commercial compost is
added to inoculate the organic
materials with composting
organisms and speed-up the
Making good, consistent
compost on-farm can be
difficult and time consuming,
so adding commercial compost
as an inoculant makes the whole
process easier and quicker.
The compost is made in open
windrows and its temperature
and moisture levels are regularly
monitored. It is turned when
necessary to stop it from
becoming too hot.
After years of trial and error, a
steep learning cur ve and help
from some experts, including
laboratory testing, the
Tidemans now have about 100
cubic metres of organic material
composting at any one time.
When compared to their
previous mulch of raw wood
chips and poultry litter,
compost provides the Tidemans
with many more benefits.
Soil condition has improved,
soil carbon levels have increased
and soils are now more friable.
Nutrient levels in soils have
increased and the Tidemans
have been able to reduce their
synthetic fertiliser applications
by 25 per cent.
Soil biology has improved
significantly with a huge
increase in earthworm numbers.
Composted mulch has
improved drainage in areas that
were prone to waterlogging,
and reduced the demand for
The Tidemans have also seen
a reduction in weed cover,
meaning they don't have to
spray as much herbicide to keep
weeds under control.
It took two to three years to
see the benefits of using
composted mulch, but the
Tidemans have no doubt it's a
worthwhile investment of time
"Composted mulch gives us
more benefits than our raw
mulch did," Penny said.
Compost easily fits into the
family's farming philosophy.
The mulch helps them recycle
nutrients back into the system;
promote healthy, well-balanced
and well-structured soils; and
foster a diverse range of
Composted mulch is also
helping them tackle their weed
In the past, the Tidemans
have made and used their own
compost teas, initially from
their own compost, then with
This year, they're getting back
into brewing their own
compost teas to produce a foliar
The compost teas help
establish a diverse range of
beneficial microbes on the
plants and reduce the incidence
Composted mulch is spread
on the soil surface under trees
at a rate of 145 cubic metres a
Every avocado tree or
blueberry bush gets one
application of compost a year,
usually in spring, but this varies
depending on time and site
Fertile volcanic region
Minimum chemical inputs
Soil gets better structure
Who: Ernst and Penny Tideman
Where: Ticoba Blueberries and
Avocados, Comboyne, NSW
What: Blueberries and avocados
Aims: To improve soil health and
structure, reduce need for
weeding, improve soil biology
Outcomes: 25 per cent
reduction in synthetic fertiliser
use, increased soil carbon levels,
increased soil friability, improved
soil structure and drainage,
improved soil biology, increased
earthworm numbers, reduced
irrigation requirements, and
reduced weed cover
Composted mulch has what it takes to improve drainage and reduce weed cover in soil.
We sell direct to industry
horticulturalists, farmers and
Poultry manure compost ideal for:
• soil conditioning
• fertilising • water conservation
Contact Phil Haby
0427 708 002
Established since 2000
Email: email@example.com | www.nuleaforganics.websyte.com.au
Composted to AS44 54
Typical analysis -- Organic Carbon 29% N4.2% P2.2% K1.8% Calcium 3.6%
and other minor elements
Haby Bulk Transport delivery
can be arranged
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