| Grain
Five-point plan offers guidance for delaying autumn
wheat drilling
Think before rushing in to drill winter
wheat after the early harvest and
now we’ve had rainfall, farmers are
being urged.
ith large areas of land
harvested much earlier than
normal, and soil moisture levels
improved, growers will be
itching to drill empty fields,
says Nick Myers, head of crop
production for agronomy firm, ProCam. But on
farms suffering from blackgrass, there’s a
compelling argument for holding back, he
stresses.
“Low blackgrass seed dormancy after the
hot, dry summer might increase the temptation
to bring drilling dates forward – because a
bigger proportion of this year’s shed
blackgrass seed is predicted to germinate
earlier. But resist that temptation,” Mr Myers
urges.
“The later you can safely delay drilling, the
less blackgrass you’ll have emerging in the
crop, and the less blackgrass seed will
potentially be shed back to the soil next
summer.
“Instead of viewing this as an opportunity to
drill earlier, think of it as an opportunity to make
worthwhile inroads into reducing blackgrass
populations for the long-term.”
On farms where delayed drilling has already
been practiced for a few years, and blackgrass
levels have already started to decline, Mr Myers
acknowledges it might be particularly tempting
to edge drilling earlier again this year. But, he
says, this could undo some of that good work.
“Some blackgrass will inevitably germinate later
anyway,” he adds.
“Obviously, you have to assess how late you
can drill based on your farm situation. If you
can’t delay all fields, at least delay those with
the highest weed burdens.”
To help growers navigate through delayed
autumn wheat drilling in blackgrass fields, Mr
Myers suggests a five-point plan:
1 Leave stubbles undisturbed as long as
possible. That way you’ll allow longer for
blackgrass seed on the surface to germinate,
but also longer for it to be eaten by predators.
Only disturb the soil at the point of having to
prepare the seedbed.
2 Avoid using inversion tillage (ploughing) if
possible. The longer you can leave buried
blackgrass seed underground, the more of it
will rot away.
3 Prepare high quality seedbeds. These will
stimulate the maximum amount of blackgrass
to germinate before planting the crop. That
way, even more blackgrass can be killed off in a
stale seedbed. Good seedbeds will also
produce better performance from soil-acting
herbicides, he notes.
4 Depending on farm situation, consider
delaying drilling until well into October.
October-drilled wheat generally contains much
less blackgrass than September-drilled. Also,
information from ProCam’s 4Cast crop
database showed winter wheat yield hadn’t
declined despite average drilling date being
delayed from 2 October to 12 October between
W
The less blackgrass you have emerging in the
crop, the less blackgrass seed will potentially be
returned back to the soil next summer, says Nick
Myers of ProCam
the harvest seasons of 2011 and 2017. Most
likely this was because any yield penalty from
later drilling was offset by crops containing less
blackgrass.
5 Adapt agronomy according to later drilling.
Select wheat varieties that can compensate for
later drilling through greater tillering, and that
are flexible with regard to drilling date. The
variety might be 1 or 2% lower yielding on
paper, but you could end up with a better crop.
Also, take steps to maximise establishment, for
example by using a seed treatment shown to
produce rapid establishment.
“As well as helping against blackgrass,
delaying drilling can also help against ryegrass,
and help to reduce take-all, eyespot and
30 | Farming Monthly | September 2018
lodging pressures in winter wheat,” says Mr
Myers. “It can also help reduce the risk of BYDV
because there are likely to be fewer aphids
about.
“Moister soils with later drilling will also
improve the uptake of residual herbicides by
weeds, while colder soils will mean residual
herbicides are broken down more slowly, so
they last longer.
“That said, do balance delayed drilling with
allowing enough time to prepare the land and
enough time for post-planting activities, such as
spraying,” he adds, “before the weather closes
in.”
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