HERBICIDE TACTICS
Drilling is done and all ready for weed control
By Robert Harris
A UTUMN herbicide application is due to start on the Cereals 98 host farm as drilling draws to a close.
Good seed-beds and timely rains have promoted rapid crop and weed emergence at the Velcourt-managed Haverholme Estate near Sleaford. That bodes well for weed control, says farm manager, Chris Redfearn.
"We aim to control grass weeds in the autumn when they are small and easier to kill. We do not often have to go back with a spring overspray."
Early-drilled winter cereals are through the ground, he adds. "Drilling has gone well. Seed-beds are good. In most fields we managed to drill into moisture."
The autumn herbicide programme for wheat will kick off with Avadex (tri-allate), applied by contractor. "We have varying levels of blackgrass across most of the farm," says Mr Redfearn. "We use Avadex where weed pressure is highest at early post-emergence."
Isoproturon (IPU) with either diflufenican (DFF) or Stomp (pendimethalin) has been pencilled in for wheats that have reached the two- to three-leaf stage. Where the mix follows Avadex, ipu rates may be reduced.
Trifluralin could be added to boost residual activity if blackgrass pressure is higher than expected or where more may emerge, especially if soils are warm when IPU can break down rapidly.
"We try to steer clear of DFF where fields are destined for oilseed rape." Label recommendations advise ploughing before sowing that crop to avoid the possibility of crop damage, but he prefers to minimum cultivate or direct drill.
Broad-leaved weeds like cleavers, ivy-leaved speedwell, chickweed, mayweed, shepherds purse, cranesbill and pansy are killed or weakened by the chemical mix. Survivors, notably cleavers, are taken out in the spring.
"We never use the full 100g rate for total cleaver control." That weed can germinate through the winter, so a follow-up spray would still be needed, Mr Redfearn suspects.
Instead, he aims to apply a maximum of 50-60g of DFF on most fields, though rates may be cut further where few broad-leaved weeds have emerged. That provides enough control until the crop is strongly established, when it shades out new competition.
Where few broad-leaved or grass weeds are found, usually on the Ruskington series gravelly sands, IPU may be used alone. "We cut back on rates a bit, partly because there is less weed pressure, and because plants can often be stressed on these lighter soils," says Mr Redfearn.
Barley will be treated with a similar programme to the wheat. But he expects to take advantage of its competitive growth habit on lighter soils where weed pressure is low, by replacing DFF with cheaper bromoxynil + ioxynil.
That helps meet the budget target of £40/ha (£16/acre) for weed control in barley. Although 50% more money has been allocated for wheat on heavier Beccles series clay loams, Mr Redfearn hopes to shave costs. "Good seed-beds, emergence and cooler temperatures auger well for weed control this autumn."
AUTUMN CROPPING
• Winter wheat (410ha) – Beaufort, Blaze, Consort, Drake, Equinox, Reaper, Riband, Rialto, Weston.
• Winter barley (134ha) – Intro, Gaelic, Regina.
• Oilseed rape (194ha) – Amber, Apex, Contact, Lipton, Pronto.
HERBICIDE TACTICS
• Avadex early post-em where heavy blackgrass pressure.
• IPU + Stomp or DFF is backbone.
• Trifluralin boost may be added.
• IPU used alone on lighter, less weedy soils.
• Contact grass weed sprays avoided if possible in cereals.
AUTUMN CROPPING
• Winter wheat (410ha) – Beaufort, Blaze, Consort, Drake, Equinox, Reaper, Riband, Rialto, Weston.
• Winter barley (134ha) – Intro, Gaelic, Regina.
• Oilseed rape (194ha) – Amber, Apex, Contact, Lipton, Pronto.
HERBICIDE TACTICS
• Avadex early post-em where heavy blackgrass pressure.
• IPU + Stomp or DFF is backbone.
• Trifluralin boost may be added.
• IPU used alone on lighter, less weedy soils.
• Contact grass weed sprays avoided if possible in cereals.
SITE REPORT
Over the coming months, we will report the key management decisions being made at Haverholme Estate as well as providing progress on plots at the site of Cereals 98.
Getting to grips with spraying…
Velcourt manager Chris Redfearn (left) has targeted IPUand DFFas the main backbone for this autumns programme which will be applied by sprayer operator
Peter Leveridge.