The best cultivation techniques to cut slug damage

Ploughing and minimal tillage are proving the best cultivation techniques compared with no-tillage for controlling slugs on one Leicestershire farm.

Sally Morris, agronomist at advisory group Hutchinsons, explains how research on her family farm showed that cultural methods can cut slug numbers sharply in high pressure situations.

The 140ha family farm at Hoby near Melton Mowbray, Leicestershire, is on heavy clay soil and is prone to slug problems, which is exacerbated by a tight wheat and oilseed rape rotation.

Losses of up to 50%

“As a result of slug damage, we’ve previously experienced up to 50% crop losses early in the season during establishment, in just a couple of days,” she says.

“Although we try our best to manage this through re-drilling, we have experienced patchy, thinner crops due to high pest pressure,” she adds.

Her trial started comparing metaldehyde with ferric phosphate slug pellets, and in a hilly area with water-run off concerns the ferric phosphate showed better results. This encouraged her to look at the effects of cultural methods.

See also: Take our free online Academy on slug control

Second trial

She started a second trial this season, comparing the effects of cultivation techniques on slug populations in winter wheat.

She tried three different techniques, namely ploughing, minimal tillage and no-tillage.

“Overall, as expected, the ploughed area was the most effective for slug control, with a maximum of only two slugs found during monitoring. No pre-baiting was required, and we only needed one application of ferric phosphate at drilling,” she explains.

The crops in the minimal-tillage area also got away and established well without too much slug damage, despite the high slug pressure experienced in this area.

Great slug pressure

In the no-tillage area, she expected there would naturally be greater slug pressure, and as a result an area of stubble was rolled three times before drilling and she compared this to an area that hadn’t been rolled.

“The results were significant, and in the no-till area which hadn’t been rolled, we experienced up to 29 times higher slug pressure in comparison with the ploughed area,” she says.

”This led us to conclude that ploughing, and min-till are the best methods for our farm when it comes to managing the number one pest,” she adds.

No till slug damage

No-till slug damage

Ploughed wheat no damage

Ploughed wheat no damage

More work

The trial work will continue this autumn, with more of a focus on soil health, but she will be repeating the trials without the no-till, as it was incredibly challenging to get the crop to grow.

She plans to reassess the plough system in comparison to min-tillage, while also considering soil biology, pH, soil profile, and worm levels as Ms Morris look to understand how cultivations affect each of these variables.

“I also have plans to upscale the cultural control trial, taking it to a new farm where they practice min-till and experience huge slug issues. The new trial will again be in winter wheat, across two fields of approximately 20ha,” she says.

“The trial work has already been incredibly useful in demonstrating the benefits of different systems and products in practical real field trials,” she adds.

Trials to monitor the effects of cultivation on slug control

(Winter wheat field of 6ha drilled into an oilseed rape stubble)

Trial one: No-tillage, direct drilled and rolled twice

  • High slug pressure
  • Pre-baited before drilling with metaldehyde
  • Ferric phosphate applied at time of drilling, with four follow up applications

Trial two: Min-tillage, drilled and rolled twice

  • High slug pressure
  • Pre-baited before drilling with metaldehyde
  • Ferric phosphate applied at time of drilling, with two follow up applications

Trial three: Plough-based system, drilled and rolled twice

  • Low slug pressure
  • Ferric phosphate applied at time of drilling, no further applications needed

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