System change aids attack on ryegrass

21 April 2000




System change aids attack on ryegrass

By Brian Lovelidge

A CHANGE of cultivation system and repeated herbicide hits throughout the rotation are helping Kevin Craggs win his war on volunteer ryegrass.

Until a few years ago, the weed was a big headache on about half his 327ha (808-acre) Shotton Farm at Sedgefield, Co Durham. Now only about 18.2ha (45 acres) is badly hit.

The weed is a legacy of rotating two-year Italian ryegrass leys around half the farm for beef cattle. Initially it was not targeted with herbicides and even spread to some fields that had never been down to grass. The straw burning ban and a reliance on fairly deep non-inversion cultivations compounded the problem.

Ploughing one year in four instead of one in seven had little effect, so two years ago the cultivations policy was completely revamped and the herbicide strategy rethought.

Mr Craggs now goes in straight after harvest with a 5.4m disc and double ring press combination to produce a shallow stale seedbed, sprays off volunteers and ryegrass seedlings with glyphosate at 1 litre/ha, and then drills with a 4m Simba FreeFlow.

The system has proved cheaper, faster and far more suitable than ploughing or heavy discing for his shallow soil and eliminates a significant proportion of the ryegrass population before drilling.

"Everyone told me my ryegrass problem was likely to get worse with non-inversion tillage, but that is not happened. We are getting well on top of it," Mr Craggs says.

The ryegrass problem is further eased by the elimination of a grass break after a big cut in beef cattle, oilseed rape replacing the grass.

Despite an intensive herbicide regime resistance to fop and dim products is unlikely to develop because the weed is being hit by a range of active ingredients across the rotation.

The first hit is always glyphosate pre-drilling. Then for OSR half-rate Co-Pilot (quizalofop-P-ethyl) or Falcon (propaquizafop) is applied early post-emergence to take out barley volunteers and ryegrass. These are hit again with full rate Kerb (propyzamide) in October or November.

In cereals, Mr Craggs relies quite heavily on IPU early post-emergence, usually at 3-5 litres/ha plus Bacara (diflufenican+flurtamone) or Javelin (diflufenican + IPU) at various rates. Any ryegrass surviving this treatment or emerging late is eliminated by Grasp (tralkoxydim) in March or April.

This spring only 4ha (10 acres) of Vertige barley and a 2ha (5 acres) headland of Claire wheat, the worst ryegrass areas on the farm, required spraying with Grasp, at 1 litre/ha plus 4 litres/ha of Output adjuvant.

"We took out the worst of the ryegrass with Roundup," says Mr Craggs. "This treatment has moved the goal posts a fair bit as it leaves the other herbicides with much less to do." &#42

WARONRYEGRASS

&#8226 Legacy of grass leys.

&#8226 Stale seed-bed + glyphosate good start.

&#8226 Shallow cultivations OK.

&#8226 Various herbicides across rotation.

&#8226 No resistance trouble.

&#8226 Reducing problem.

Stale seed-beds are helping Kevin Craggs clobber volunteer ryegrass hard. One or two passes with this disc/press straight after harvest gives a good chit ready for spraying and drilling with no further cultivations.


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