Home' NZ Dairy Farmer : September 2013 Contents The Dairyman September 2013 57
FERTILISER co-operative Ravens-
down is continuing to push for the
return of its eco-n product to help
prevent nitrates leaching from farmland
after its removal from commercial shelves.
Nitrification inhibitors like eco-n -
with the active ingredient dicyandiamide
(DCD) - were withdrawn voluntarily by
fertiliser manufacturers after traces of
DCD were found by Fonterra in dairy
products in September last year and
publicly revealed in January.
DCD was used by less than 5 per cent
of dairy farmers, mostly in the South
Island, in autumn through to early spring
to help reduce nitrate leaching from cow
urine patches and to cut back nitrous
oxide gas emissions.
Ministry of Primary Industries officials
said the levels were not a food safety
concern, but Ravensdown, and rival
co-operative Ballance Agri-Nutrients,
removed products from sale as a precau-
tion because there were no food safety
standards for DCD.
Chief executive Greg Campbell said
Ravensdown continues push for eco-n
Ravensdown was working with the MPI
to develop an international code that
would be acceptable overseas.
"We are still pushing on with the
Government and MPI on that. Clearly,
our farming needs some assistance with
lowering the environmental footprint. It
was a good tool and possibly the only tool
in the tool box so farmers are continually
looking to us to have the product. Until
we get the codex (international standard)
we are in a holding position."
He said developing an international
standard normally took five years, but the
co-operative was hopeful this could be
reduced to several years.
"We are hopeful it will be years. It's
cold comfort to farmers for helping them
for nitrate leaching or environmentally
regulated compliance which we support
by the way as a company. Farming should
be done in a sustainable fashion."
The ban on the nitrification inhibitor
was a "technical rejection" as there were
no international standards.
Campbell said the co-operative was
looking to invest in research and develop-
ment adding value to shareholders.
About $12 million has been invested
in developing precision fertiliser appli-
cation for hill country farmers with the
programme receiving $5.1m from the
Government as part of the Primary
Growth Partnership project. The project
is looking at remote sensors to assess
nutrition levels on hill country farms.
Further development in on-farm
spreading technology resulted in the
launching of Smart Maps, a new digital
mapping tool where farmers can view an
online aerial map and draw or alter fence-
lines for paddocks, blocks and manage-
Ravensdown wound up a tough
financial year ending May with a small
profit and no rebate, not aided by eco-n
being removed from shelves until new
international standards are set. Campbell
said the suspension of the company's
eco-n product was another one-off event
impacting the result.
"The suspension of eco-n, a product
used to limit nitrate leaching and green-
house gases, had an effect on the results.
"Losing the profit from eco-n and the
cost of stock disposal had an impact of
seeds are typically cast aside as chaff and
redistributed over the field.
Four methods have been established to
capture and destroy weed seeds at crop
One method involves the use of chaff
carts, pulled behind a grain harvester, to
collect the weed seed and other discarded
plant material. These materials are then
either burned or used as livestock feed.
A LONG-TERM study in Australia
offers a new weed control model for
This mechanical method targets
weed seeds during harvest, reducing the
quantity of weeds that can grow in future
The journal Weed Technology
discusses the harvest weed seed control
system in the latest issue: To reduce the
levels of weed populations, weed seeds
are destroyed at or after grain harvest.
Combined with herbicide use, this system
may further lower weed populations. The
effects of this system were observed in 25
large commercial crop fields in western
Australia over 10 consecutive growing
An attribute of most weed species is
that the seeds are attached to upright
plants, allowing those seeds to be
collected during harvest.
Up to 80 per cent of annual ryegrass
seed production is collected during a
commercial grain harvest. However, these
Another method uses a chute to
disperse the seed from the harvester into
narrow windrows, which are subsequently
burned. A baler attached to the harvester
offers another method of disposal, creat-
ing bales of chaff and straw residue for
Finally, a mechanical device
(Harrington Seed Destructor) uses a cage
mill to process crop chaff. This device
could destroy 95 per cent of the weed
seed contained in the chaff.
The authors emphasise an integrated
approach, as opposed to a stand-alone
technique, in order to successfully utilise
the system in agriculture throughout the
world. In this study, the only fields that
reached the targeted goal of low weed
density were those that employed the
weed seed harvest system in conjunction
with early-season herbicides.
One of the potential advantages offered
by this system is that removing most
of the weed seed will lessen its ability
to develop resistance to the herbicides.
Resistance to herbicides among weed
species has become widespread and is
negatively affecting agriculture, particu-
larly in Australia.
As weeds continue to become resistant
to multiple herbicides, new weed control
strategies are needed to ensure optimal
Seeds attach to upright plants such as ryegrass.
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