Ashburton Courier: November 18, 2021

www.ashburtoncourier.co.nz
App helps to manage weed
Anew free web app has been
designed to help farmers,
landowners and regional councils
manage acostly weed that has
resisted eradication efforts in New
Zealand for over acentury.
Nassella tussock (Nassella
trichotoma) occurs in drought­prone
grasslands, mainly in the Canterbury
and Marlborough regions.
It is unique in that it is the only
weedinNew Zealand to have had its
own Act of Parliament, the Nassella
Tussock Act 1946. The Act legislated
for the establishment of the
Marlborough and North Canterbury
Nassella Tussock Boards tocoordinate
central government­funded
control programmes, aresponsibility
now resting with the regional
councilsthrough Regional Pest
Management programmesunderthe
Biosecurity Act 1993.
Thehistoricalcontrol programmes
have substantially reduced the
weed’s populations.
Although eradication has proven
elusive, a17­year study in
Canterbury, published in 2016,
showed that the population density of
the weed across 878 invaded farms in
the Hurunui District is stable at
about 15 plants per hectare. Grubbing
of the plants hasbeen responsiblefor
maintaining the equilibrium
according to on­farmexperiments
and modelling.
Left uncontrolled, the modelling
indicates that the weed’s populations
will increase, potentially reaching
the economically damaging
monocultures of the past.
The new app, developed by
AgResearchwith funding from the
Ministry of Business Innovation and
Employment in collaboration with
Nassella tussock occurs in drought­prone grasslands and mainly in the
Canterbury and Marlboroughregions.
PHOTOSUPPLIED
Environment Canterbury, provides a
tool to visualise arangeofgrubbing
strategies.
The app deploys apopulation
model that counts the numberof
nassella tussock plants in summer
and winter in each of seven different
life stages of the tussock and keeps
track of their contribution to thetotal
tussock population oversuccessive
years.
EnvironmentCanterbury
biosecurity officer MattSmith says
nassella tussock wassuch an issue in
the mid­20th Century that some
North Canterbury farmers
abandoned theirproperties because
they were no longerprofitable.
Many decades of hard worksince
then have returned plant numbers to
amanageable level.
The app can be found via the
nassella tussock page on the AgPest
website.
Infilledpits contaminate soil
Acompletedresearchproject about
historical landuseinthe Ashburton
Districthas found themost common
sourceofsoilcontaminationwas
infilledpits.
Affectedpropertyownershave
been sent letters outlining their
property’s history andits inclusion
on theListed LandUse Register.
Regional councils throughout New
Zealand are responsible for
identifying potentially
contaminated land and making this
knowledge publicly available. Many
of the urban sitesinthe district have
already been identified.
The latest research used aerial
imagery, so the new information
mostly relatestorural­based
activities best­seenfromtheair,
such as sheepdips,farmrubbishpits
andhorticultural land uses. It
identified about 1400 sites where
hazardous substances might have
been used.
Of these, 700wereinfilled pits
which may have been filled with
rubbish or uncontrolled materials,
around 500weresheep dipsorspray
race operations, and around70were
horticultural sites where persistent
sprays may have been used.
The results areconsistentwith
what’s been foundelsewhere in
Canterbury.
“Property owners have aright to
know thehistoric use of theirland.
It’sour role to record that
information and let the landowner
know,” Environment Canterbury
(ECan) contaminated land science
team leader Graham Aveyard said.
“This is the starting point of a
process which identifies land that
has beenusedfor activities that
mayleadtocontamination.
“I wouldlike to reiterate that
most people will not need to do
anything. It’s only if you’re
considering subdividing or
distributing the soil on asitewhen
you’d need to contact the
Ashburton District Council for
advice,’’ Mr Aveyard said.
The research focused on the
Ministry for the Environment’s
Hazardous Activities &Industries
List (HAIL).This caninclude
formermarketgardensand
orchards,landfillsand rubbish
pits,sheepdips, timbertreatment
sites,gasworks, fuel suppliers and
service stations.
Ashburton Courier, November 18, 2021
Spray hazard
23
Waka Kotahi NZ Transport Agency is reminding
landowners to make sure water from irrigation
systems are not spraying across the highway.
It’saseasonal reminder with the irrigation
season well under way.
Waka Kotahi maintenance contract manager
for Mid and South Canterbury John Keenan
said as well as being wasteful of water, it can
create aslippery surface on awarm, sunny day.
Motorcyclists and cyclists in particular need
to takecare on wet roads.
‘‘If drivers see spray water hitting the
highway,slow down and let us know so we can
contact the land­owner,” he said.
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10 Tin 2021 Snow
Poweroutage
following fatality
Policehaveconfirmedthe nameof
theperson whodied followinga
single­vehiclecrash on Ealing
MontaltoRoad, Carewlastweek.
He was Jonathan Rutherford, 32,
of Oxford.
The investigation into the
circumstances of thecrash is
ongoing.
Mr Rutherford died and up to 60
households andbusinesses were
leftwithout powerafter the crash
on November11. Emergency
services werecalled to the site at
9.40pm.
Apolicespokesman saidthe
vehicle reportedly collided with a
concrete barrier.MrRutherford
died at the scene.
PowersupplierEANetworks
reported60customerconnections
werewithoutpower for22hoursas
result of theaccident after the
vehicle collided with aRing Main
Unit,removingitfromits
foundations.
The destroyed unit was replaced
to allowpower toberestored.It
waslikelymore work wouldbe
needed at the site in future, but the
focus in the short­term was
restoringpower to customers.