Cultivator helps in blackgrass battle

Agronomists and equipment makers have come together in a rare joint effort to develop cultivation tools that could help growers in their efforts to tackle blackgrass.

The initiative is part of the Blackgrass Centre of Excellence trials, which Hutchinsons is using to help understand how season, previous cropping, cultivation and herbicide programmes affect control of this challenging weed.

Cambridgeshire cultivations equipment specialist Cousins of Emneth has been tasked with developing novel implements that encourage blackgrass to chit for spraying off or that sow oilseed rape without encouraging blackgrass to germinate by minimising soil disturbance.

“It’s very interesting for us to be involved with agronomists in designing equipment for a specific purpose like this,” says Laura Cousins. “We usually look at equipment design from the point of view of using metal to work the soil.”

A prototype tine-and-press ring cultivator devised by her father John Cousins is designed to work effectively no deeper than 100mm. The aim is to move the soil sufficiently to get a flush of blackgrass that can be sprayed off before further cultivation and/or drilling.

“It’s very difficult to get an implement working evenly at such a shallow depth,” she adds. “But the objective is to avoid burying seed or bringing older material to the surface.”

Micro Wing tinesTwo sets of Cousins Razor Ring pressed-steel shouldered discs are spaced some distance apart to stabilise the implement. Staggered rows of rigid tines positioned ahead of them have points designed to “stir” the soil at shallow depth.

“Our experience so far is that this will produce a seed-bed suitable for a range of different cultivator drills,” she says. “And because power requirement when working so shallow is very low at around 50hp/m, it will be possible to have wide working widths to cover a lot of ground using a modest speed to maintain the precise depth control required.”

Another commercially available solution to the blackgrass issue is the Micro-Wing tine for the V-Form subsoiler. This implement is commonly used with a broadcaster for sowing rape while loosening soil at depth, which inevitably causes a fair amount of surface disturbance.

“It’s very difficult to get an implement working evenly at such a shallow depth. But the objective is to avoid burying seed or bringing older material to the surface.”
Laura Cousins

The Micro-Wing works only 150-180mm deep, creating a strip of tilled soil 100mm wide; seed is broadcast on to this strip from fishtail outlets.

While this foregoes the benefits of deep soil loosening, minimising blackgrass germination in this way will result in a much lower population of viable plants returning seed once in-crop herbicide treatments have done their job.

Hutchinsons technical manager Dick Neale emphasises that using glyphosate to control volunteers and germinated weeds in the stubble is essential to remove competition to the young rapeseed crop.

While there is an inevitable trade-off between using a small cultivator point to minimise soil disturbance and the service life of such components due to wear, Cousins has used boron steel combined with Hardox for maximum resistance.

Lemken has teamed up with Agrii to establish a five-year trial to better understand the effects of cultivation systems on blackgrass.

It also aims to help growers make best use of cultural control methods through its Weed Wise initiative, that sets out to explain how best to use different implements.

“For example, ploughing properly will bury weeds effectively, and that’s not always achieved on farms today,” says Mark Ormond of Lemken. “We also explain why it’s better to make two passes when making a stale seed-bed than just one.”

Lemken’s credentials for taking this approach are based on the success of its two best-selling implements: the Smaragd sweep point cultivator with mixing discs for stale seed-bed creation on sandy soils and the Rubin high-speed shallow disc cultivator for clay soils or where there is a lot of surface straw.

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