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How five growers control their black-grass


In June we introduced the five growers embarking on the 5x5 project. In this issue we catch up with them as they assess their black-grass control this season.

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Find out how 5 growers go about controlling black-grass #5x5 #black-grass

Suffolk, Julian Swift

Suffolk, Julian Swift

Julian Swift steeled himself from the beginning for a bad black-grass season in his part of East Anglia, but thinks some judgement and much luck meant his land was hit much more lightly than some in the region. But the spread of the weed, both into new areas and places where it was thought to be under control, continues to be a worry.


He says: “I knew in November nothing was going to kill the big plants it appeared we were likely to get if we didn’t have some frost. The lack of that followed by a difficult spring for spraying, plus a warm, wet June the black-grass loved, meant nothing was a surprise.


See also: Yorkshire farmer looks to the skies for strategy to control black-grass


“It kept growing and tillering, resulting in plants with huge numbers of tillers – it was difficult to find the base of the plant in some cases. So unsurprisingly, we didn’t get brilliant results from our control programme.


“But although I wasn’t expecting such heavy infestations in some areas, I don’t think we’ll be hit too heavily for yield. Altogether, of our 2,400 hectares we’ve only had to resort to spraying off about half a hectare in patches of badly infested crop.”


He describes his 5x5 field of Evolution winter wheat as looking ‘awful’, but with half looking better than the other half, thinks it should still yield seven-eight tonnes/ha.


“I could plough this field this autumn, but it hasn’t been ploughed for 25 years, and I’m reluctant to revert to that.”


Instead, Mr Swift plans to plant a cover crop after harvest, followed by peas in spring.


“Usually this would go into oilseed rape, where any autumn failure would mean it would still be possible to plant something else in spring. With peas, we won’t get that insurance.


“I think cover crops have an important role to play in suppressing black-grass establishment by creating a better soil structure, but the blend is something we need to ensure is right. This year our barleys drilled behind a forage radish plus black oats mix looked very good, and I think the radish definitely plays a significant role in soil improvement. The right cover crop blend is about more than the sum of its parts. We also plan to ensure we retain the maximum benefit from that soil improvement by band-spraying out the cover crop and drilling into the sprayed-off strips.”


While the worst black-grass was restricted to a few locations, the more serious issue is the weed’s appearance in new places, and those where it was thought to have been eliminated, says Mr Swift.


“One field that’s had only two winter crops in seven years is still far from spotless, while in winter bean crops where we thought we’d got black-grass under control, we’re still seeing plants appearing.”


Like others, this season he noted black-grass plants grew bigger heads, leaves and stems.


“I have seen some fields being fallowed as a method of control, but I’m not convinced by this. I think it shuts down the soil biology, in turn damaging the structure, and hence the drainage, creating a situation black-grass loves.


“We’re in the middle of a programme of drainage updates, and it’s not surprising to see how the presence or otherwise of black-grass in a field mirrors its drainage map.”


One other thing Mr Swift is investigating is the effect of drill coulter type and drilling speed on soil disturbance.


“We’ve purchased a Weaving disc drill to run alongside our Horsch tine coulter machines this year, and will be looking at what works best on different fields/soils. Minimising disturbance can be as much about topography and speed as soil type and coulter format – it was clear in on-farm demonstrations last year that when running down hills, with less demand on the tractor, greater forward speed resulted in greater disturbance and more black-grass germination.”


Treatments and black-grass head counts:


Timing Date Treatment
Drilling 13/09/2015 Wheat
Cultivations None-inversion (year two). 8m Vaderstad Seed Hawk
Pre-em 13/09/2015 Sunfire 0.48 litres/ha
Post-em 28/04/2016 Broadway Star 265g/ha + adjuvent
Crop canopy cover at flag Thin: 1.5 out of 5
Black-grass tillering Mean: 6.8 heads/plant
Black-grass control Large area of very poor control

Source: Bayer



Northamptonshire, Keith Thompson

Northamptonshire, Keith Thompson

“The 5x5 field is better than we’d hoped for. It is not at levels where we can control it with the knapsack, but I hope it will be by the end of the five years,” says Keith Thompson.


Black-grass will not impact on yields this year and the crop looks well, he adds. “Delayed drilling made the biggest difference. We used a standard pre-em. The treatment was pretty average this year but delayed drilling meant we had less black-grass to deal with.”


Next season the 5x5 project field will be drilled with spring beans followed by wheat. “Hopefully we’ll see progress in a couple of years.”


On contract-farmed land, he has done a limited amount of applying glyphosate to growing crops to control black-grass. “It’s never enough. The cheapest option in the long run would be to spray but cashflow sometimes determines it.”


More generally, he says this year he has seem some of the most vigorous black-grass ever. “Each plant has loads of tillers. That’s possibly why we’re seeing so much around. Each plant has 20-30 tillers and wheat is not crowding it out. Barley is best but it [black-grass] is still coming through.


“There wasn’t a winter and it carried on growing.”


Treatments and black-grass head counts:


Timing Date Treatment
Drilling 23/10/2015 Wheat
Cultivations Plough, press, drill
Pre-em 20/11/2015 0.6l/ha Liberator + 2l/ha Defy + 3l/ha Anthem
Post-em None
Crop canopy cover at flag Thin: 2 out of 5
Black-grass tillering Mean 4.75 heads/plant
Black-grass control Some surviving late and small

Source: Bayer


Cambridgeshire, Leonard Stamper


A min-till approach to a depth of 5cm on the 5x5 project field has provided better control of black-grass than deeper cultivation elsewhere on the farm, says Lenny Stamper. “There was better chit in autumn and stale seedbeds got rid of quite a lot. There won’t be a yield penalty.”


Elsewhere on the farm, he believes this year’s vigorous black-grass populations are a result of the mild winter. “It’s shot away and done well and the chemical didn’t last as long because of the mild winter.”


See also: VIDEO: Five-year plans to tackle black-grass


While he did contemplate spraying off areas with glyphosate, in the end he did not. “We wanted to get something off it.”


Next season the 5x5 project field will be sown with oilseed rape. The same shallow cultivation method will be used.


Treatments and black-grass head counts:


Timing Date Treatment
Drilling 11/10/2015 Wheat
Cultivations One-pass with Horsch Joker, drilled, shallow cultivation
Pre-em 13/10/2015 4l/ha Crystal + 0.2l/ha Hurricane (DFF)
Early post-em top up 12/11/2015 0.6l/ha Liberator
Crop canopy cover at flag Good: 4 out of 5
Black-grass tillering Mean: 2.89 heads/plant
Black-grass control Patch of poorer control

Source: Bayer


Cambridgeshire, Abbots Ripton Farming Company

Cambridgeshire, Abbots Ripton Farming Company

Black-grass control plans got off to a sound start this season for Abbots Ripton Farming Company, with good pre-emergence treatment results and timely Atlantis (mesosulfuron + iodosulfuron) application. But the combination of high pre-existing populations and, in particular, lack of winter frosts undid much of that good work, resulting in strong tillering and the growth of big plants.


The estate’s cropping manager Paul Drinkwater says: “We’re containing the problem, but we’re not yet reducing it.


“Beginning our weed control with Avadex Excel, Liberator, and Stomp Aqua gave us good results, but in many fields we were starting from high populations. Post-emergence Atlantis took some out, being particularly effective where it was applied in November, and when walking fields in February/March the problem appeared to be at manageable levels of 3-4 plants/sq.m.


“However, the lack of frost right through the winter was a bigger help to the black-grass than anything else, and that not only helped the plants tiller tremendously, some producing 20 tillers or more, but also resulted in some big heads.


“As a result, in places we have a lot more than I expected, and there will be a high seed return. We applied glyphosate to the worst patches, and have sprayed off around a hectare in total.”


The field chosen for the 5x5 trial, though, has come through better than hoped for, says Mr Drinkwater.


“As it encompasses a number of different soil types, I knew it would present a challenge. But while the black-grass is proving a struggle to control, by mapping the patches we are keeping it in place and making it easier to target, saving time and money over blanket treatment.


“I think if there’s one thing we can perhaps do more with it’s delayed drilling, but with a large acreage to cover it’s not always easy to sit still if conditions are good come the third week of September.


“To help here, we are also looking more closely at how we manage fields which are actually suited to drilling early – those which we’ve been able to clean up and those which have no history of black-grass.


“The managers of the individual farms across the estate are also reviewing the ploughing history of each field. Our skirt fen land, of which our 5x5 project field is part, is more challenging to manage from a black-grass point of view than our clay soils. That’s primarily because we use the plough every four years on the clays, which are all in a combinable crop rotation which is otherwise under minimum tillage.


“On the skirt fen, where the rotation is mainly first wheats broken by peas, beans, potatoes and beet, we plough almost every other year, exposing buried seed again after a relatively short time. There may be more we can do with rotational ploughing on our worst black-grass land.”


Treatments and black-grass head counts:


Timing Date Treatment
Drilling 14/10/2015 Wheat
Cultivations Power harrowed, drilled, rolled
Pre-em 16/10/2015 Liberator (0.6l/ha) + Stomp (2.5l/ha) + Hurricane (0.1l/ha). Avadex applied 24/10/2015 (15kg/ha)
Post-em 18/11/2015 Atlantis (0.4kg/ha) + Defy (3l/ha) + Biopower (1l/ha)
Crop canopy cover at flag Good: 4 out of 5
Black-grass tillering Mean: 11.6 heads per plant
Black-grass control Large area of poorer control

Source: Bayer


Norfolk, James Thomas

Norfolk, James Thomas

To date, black-grass populations appear worse on James Thomas’ loam soils, despite the fact most would argue it typically thrives in heavier soil types.


Where Mr Thomas has used a spring Atlantis application, crops look relatively clean, only slightly worse than last year. However, where Atlantis was not used, he believes black-grass populations are likely to affect final wheat yields.


He says: “Black-grass control has been good and bad, there are some areas I did not treat with Atlantis and now I wish I had as black-grass is worse in those fields.


“Where we have really bad black-grass, it is likely to affect yield, but this only really affects three or four acres.”


Like many, Mr Thomas has noticed black-grass has tillered aggressively this season; something he thinks has been driven by wet, mild weather.


“I don’t think black-grass populations have been helped by having such a wet, mild winter.


“High rainfall meant a lot of chemical was lost down the soil profile and it stayed mild throughout the winter, so black-grass was able to grow away quickly heading into spring.”


Despite this, black-grass populations haven’t been such where he has had to resort to spot spraying with glyphosate.


Control within his nominated 5x5 field has exceeded his expectations, highlighting the importance of a robust pre-emergence programme and targeted post emergence applications.


Treatments and black-grass head counts:


Timing Date Treatment
Drilling 03/10/2015 Wheat
Cultivations Deep min-till, Vaderstad drill
Pre-em 20/10/2015 Crystal (2l/ha) + Liberator (0.3l/ha) + Anthem (2l/ha) + Hurricane (0.1l/ha)
Post-em Apr-16 Atlantis 0.4kg/ha + Biopower
Crop canopy cover at flag Thin: 2 out of 5
Black-grass tillering Mean: 2 heads/plant
Black-grass control Very good, one small patch

Source: Bayer



Year 1 conclusions

Bayer farm business manager and 5x5 project manager summarises the findings of the first year:


  • Four of the five project fields have black-grass which is difficult to control, some with very high populations. James Thomas’ field is the exception, with a sensitive population but where care is needed to prevent future spread of the weed and development of a resistant population
  • All fields have survivors this year, some at disappointing levels
  • The pre-em residuals started by seeming to work well, but the unusually mild winter allowed for more survivors than usual and unfortunately they tillered heavily, especially in thinner crops
  • Atlantis (mesosulfuron + iodosulfuron) was used on two fields. It worked well at Mr Thomas’ but left many survivors, due to resistance, at Paul Drinkwater’s. Where it was not used, growers did not think they would get much control from it due to resistance
  • Only Keith Thompson’s project field was drilled late – October, 23. It helped a lot
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