How to start the new cropping year in Scotland

Article overview

Current situation (19 August)

All the winter barley has been harvested and, from what I've heard, yields are slightly better than anticipated. They're not record-breaking by any means but given the weather growers are relatively happy.

In the south of Scotland most of the oilseed rape has also been cut, while further north there is still area to be cut. That's likely to be a mixed bag. Combines have also started on wheats in the Borders, but not much has been touched in Fife or beyond.

1) Stale seedbeds make sense

If weather allows you to do a stale seedbed, then do it. I'm aware of farmers who have already done stale seed beds by putting a set of shallow discs through stubbles following winter barley.

With the moisture likely to come this week in August they should have had a nice chit of volunteers before getting oilseed rape in the ground. This will help the oilseed rape by removing competition from the volunteer barley.

But the same applies after oilseed rape crops that have been cut. If you can tickle the surface and get a chit on that seed before sowing wheat, again the competition from volunteers will be reduced and it will help the grower and crop.

You don't need a long time to do a stale seedbed. I think some growers think they might need three weeks but it really doesn't need to be that long. You're just wanting a chit. If it's warm and there's moisture, then plants will germinate quickly so you are looking at possibly 10 to 14 days in some cases for a stale seedbed.

Where fields have potential grass weed issues, for example couch or bromes, then stale seed beds are even more important. Taking out these kinds of obnoxious weeds will help you no end before you drill the next crop.

Timing of glyphosate sprays depends a little on weather, weed type, and whether you’re also worried about destroying any green bridge for aphids transmitting barley yellow dwarf virus.

If you are looking to destroy a green bridge then our research suggests that glyphosate applications should be at least 10 days ahead of sowing. This will reduce infections of BYDV because the aphids will have moved on with no green material left to feed on.

The latest you can leave glyphosate applications, where you’re less worried about a green bridge, is around 48 hours ahead of drilling. Perennial weeds, such as thistles, might need a little longer to be controlled.

2) Test overwintered seed for germination

If you have leftover seed from last autumn and let's face it plenty of growers probably have, then before planting it this season make sure you've done a germination and vigour test.

The results will affect your seed rates so don't just think it will be fine, get it tested because if you end up sewing something and only 70% of it comes through the ground it's not going to be good.

3) Sow, roll and spray

After last season there will definitely be growers drilling wheat earlier in September this season. Current conditions point towards it being possible to achieve decent seedbeds.

Sowing, rolling and then spraying is key. If you can sow the field, then you can roll it, and if you can roll it, you can spray it. Rolling will obviously depend on your soil type with some on heavier ground deciding against it, especially after last year where it contributed to poor establishment by keeping the water table artificially high. But generally it helps to consolidate ground and helping to achieve good seed-to-soil contact.

Pre-emergence herbicide sprays are best applied within 48 hours of drilling, if possible. Liberator (flufenacet + diflufenican) is probably your starter for 10 in terms of product choice.

For the majority of growers if you just have annual meadow grass and some broadleaf weeds then Liberator at around 0.3 L/ha does a good enough job.

Where you are unlucky enough to have weeds like rats tail fescue like we have at the Edinburgh weed screen the full rate of 0.6 L/ha will be required. That will also be the case for more common weeds like Italian ryegrass and bromes.

With these more difficult grass-weeds, including black-grass, you will likely need to mix in a product like Proclus (aclonifen) to get on top of it. Remember Proclus must be used pre-emergence.

There are other options, including ones containing metribuzin. Metribuzin brings a little contact activity so can be used early post-emergence, and will give control of difficult broadleaf weeds, such as groundsel and bur chevil.

One final herbicide-related note: Liberator can no longer be used in winter oats. The Chemicals Regulation Directorate (CRD) ruled winter oats should be reclassified as a major crop, which means the extension of authorisation for minor use (EAMU) has been lost.

4) Is it too late for oilseed rape in September?

Oilseed rape establishment in September really comes down to the weather. Most growers will have tried to establish oilseed rape in August with some farms already sown up.

The cut off for drilling oilseed rape in September is probably the first couple of weeks but it does depend on the weather. If you're planning to drill or see drape in September then go for a hybrid variety with its increased vigour and speed of establishment. Those characteristics will be crucial at this stage.

Cabbage stem flea beetle fortunately hasn't been a huge thing yet in Scotland. It's not widespread but we do get little patches sometimes. If you want to follow cabbage stem flea beetle migration patterns then Bayer’s Magic Trap, which is a water trap with a camera attached, allows you to do that using an app on your phone.

Also keep your eyes peeled for slugs, which could be a challenge this autumn. Use layers mash under a slate to check numbers.

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