Crop Watch: Rain lottery sees patchy OSR crops

Deciding when to drill wheat in blackgrass areas is a hot topic this week and Giles Simpson says most are holding their nerve in the West on areas where blackgrass is a problem.

However, in the North, Patrick Stephenson says delayed drilling is seldom a option given the conditions in October and he prefers to tackle the weed by changing rotations and using a good pre-emergence stack.

In oilseed rape, Kevin Knight says establishment has been a rainfall lottery, leading to patchy germination regardless of drilling date.

Marcan Mann adds that patchy emergence has left some growers faced with either re-drilling with a winter crop this autumn, or leave it until spring to allow blackgrass germination.

North: Patrick Stephenson

AICC (Yorkshire)

patrick stephensonWith the last dregs of harvest being completed, everyone is flat out drilling.

Seed-beds, up to now, have been excellent and part one of next year’s cropping is going well.

I have listened to and agreed with the blackgrass experts about the value of delayed drilling until mid-October. Unfortunately, this is seldom an option for the North.

We are far better altering rotations and ensuring that crops are drilled in good conditions and sprayed pre-emergence with a stacked herbicide mixture.

Flufenacet-based products will be the cornerstone of the programmes and, despite a straight formulation being available, co-formulations will be my preferred recommendation.

The first drilled wheat’s are now emerging and have had no slug problems so far. Very few pellets have been applied and with good seed-beds, I am hoping this remains the case.

The emerging crops will be closely monitored and top-ups of further herbicides will be applied as required.

See also: See the archive of all our agronomist reports

The Rothamsted aphid monitor is already picking up high numbers of cereal aphids.

Crops drilled early with Deter (clothianidin) seed dressing should be covered for about six weeks from drilling, but those not dressed will need close monitoring and potentially an early spray.

Understanding which aphids are present will help guide product selection.

Gout fly is also an issue for these early-drilled crops. The eggs are 3-5mm long, cylindrical, cream coloured and lay on individual leaves. Pyretheroid sprays offer good control of the eggs if levels are deemed to be high.

It is sad to say but the march of cabbage stem flea beetles from the South is carrying on at a pace and we have more issues this year than last.

Crops drilled after winter barley in mid-August have shot out of the ground and are starting to look big. Unfortunately, those drilled later are battling with flea beetle and to a lesser extent slugs.

South: Kevin Knight

Zantra (Kent) 

Kevin KnightWell, that was the least stressful (dare I say relaxed) harvest I can recall for some time.

Yields varied widely – 100 hours less sunshine than average during June equates to around 10 days less grainfill.

Early-drilled wheat on light ground and winter barley, ran out of steam before the sun came out.

Second wheats and spring cereals were still green and ripening during July and yielded fairly well.

Wheat yields were between 8t/ha (barley yellow dwarf virus) and 10.5 t/ha, with 9t/ha being good this season, though south of 7t/ha was possible where timings were wide of the mark or corners cut too hard.

Oilseed rape came in above 4t/ha, winter beans did well, spring beans variable dependent upon ground from 3t/ha to just under 6t/ha, most around 4.5 to 5t/ha.

Oilseed rape establishment has thus far been a rainfall lottery. Kent had a dry August and 4-76mm of rain over September (all in the second half).

Most have had a patchy germination regardless of drilling date which concentrated flea beetle and slug activity on the plants that are there.

Difficult decisions remain over some fields, as re-drilled patches and broadcast top-ups are playing catch up.

Boosting establishment of rape seedlings is key to even up prolonged germination and plants stressed by drought and grazing from flea beetles, slugs, sawfly and diamondback moth in places.

Once emerged, foliar feeds of P, K, boron and zinc can give seedlings the wings they need to get away. Applying some sulphur in early autumn will improve uptake of seed-bed nitrogen and yield potential.

Wheat drilling is just starting, though only on clean fields as stale seed-beds have yet to come to life, and residuals need moisture for best effect.

Where blackgrass is an issue it would be pointless. If you thought last year was a perfect storm for grassweeds, just try drilling cereals early in a dirty field now and watch the wholecrop silage grow away when the rain comes in. You’ve been warned.

Slug pressure is high despite the dry weather, they resurface at any hint of moisture from rain or heavy dew, so monitor emerging crops closely.

East: Marcus Mann

Frontier (Essex)

Marcus-MannNo sooner is the harvest over and the new season begins. It fascinates me how a small country can have such varied weather across its regions.

Essex appears to be missing the bands of rain which are frequenting the rest of the country with some areas not having any substantial rain since the monsoons in June.

This has had a detrimental effect to oilseed rape which has suffered more through lack of moisture than flea beetle at present.

Crops which were drilled early, particularly where following winter barley have retained some moisture and emerged. Those drilled slightly later have remained in dry soils and sat dormant for long periods.

This has resulted in patchy small plants that have lost vigour and decisions are being made towards their viability.

Options are either to re-drill with a winter crop this autumn, or leave for the spring to allow blackgrass germination.

Also being taken into account is the shortening day length and cooling night temperatures.

Winter cereal drilling is under way and generally seed-bed conditions have been good.

However, the dry weather has affected the germination of high dormant blackgrass this year with very little currently being seen on stubbles. This is encouraging later drilling of areas where past history has shown blackgrass issues.

This has great merit, but will also come with its own caveat. Soil conditions will be analysed as we get further into the autumn, as the risk of drilling late and compromising the crop, will lead to less competition and further grassweed issues later on.

As a general rule, if it looks like conditions may become too saturated to apply the residual, don’t drill.

In terms of the residual programme, most will begin with a tri-allate application and be followed by a full flufenacet programmed approach.

Diflufenican and pendimethalin will be the main blackgrass partners, with either prosulfocarb, flurtamone or picolinafen being added for further ryegrass control.

West: Giles Simpson

Pearce Seeds (Wiltshire/Dorset/Somerset)

Giles-SimpsonMother Nature is still in charge and there’s nothing we can do. Harvest has only just finished here in Dorset with the last of the cereals cut this week.

In general, the harvest has been average, winter barley and oilseed rape ranged from poor to average. Hybrid barley was the exception out yielding the conventional varieties.

Winter wheat yields were better than expected with very good specific weights. However, spring cereal crops have done the best and, in a lot of cases, have outyielded winter crops. 

Oilseed rape has gone into generally good seed-beds and has come up evenly. Slugs have been a nuisance, but have been kept under control with a mixture of metaldahyde and ferric phosphate pellets. Flea beetle has generally not been a problem.

maize harvesting

© Tim Scrivener

Winter wheat on non-blackgrass ground has started to be drilled, but where blackgrass is a problem, most people are holding their nerve and have not drilled. The weather forecast is helping this decision.

I don’t think anybody is drilling single-purpose dressed seed this year after last year’s mild weather and pressure from aphids.

It’s not every year that you see combines working in fields next to forage harvester cutting maize crops, but this year we have.

The early maize varieties are fit and the foragers are going and yields look as if they will be good, but not exceptional. Remember how cold it was in the spring.

This will mean that ground conditions are suitable for crops to be drilled into the maize stubbles, so hopefully, we will reduce soil erosion.

Where no crop is to be drilled, then the ground does need to be cultivated to reduce the run-off. There will be no excuse this year, as time and ground conditions are on our side, especially if you have drilled the early-maturing maize varieties.

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