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In this issue... Precision progress page 62 Clover care page 77 Putting N in its place Cropping route to regen ag Net Zero nutrition page 44 Beet for bees page 89
Opinion
Volume 23 Number 2 Talking Tilth - A word from the editor.
4
February 2021 6 Smith’s Soapbox - Views and opinions from an Essex peasant…..
60 Tech Respect - CPM ’s machinery editor surveys the search for UK Ag’s next step.
91 Last Word - A view from the field from CPM’s technical editor.
Technical
8 Weed management - Thinking differently about weeds
Is it time to look at managing weeds in a different light?
14 Weed management - Herbicide hints for spring
Weeds may need attention as winter turns into spring.
18 Forward-thinking farmers -Tests and tools to track and trace
Decent diagnosis of in-field issues ensures the right product is applied..
22 Theory to Field - Can less be more?
Improving productivity is all about using inputs more efficiently.
26 Disease delve - The dynamic force behind yellow rust
Editor Yellow rust stood out as the disease to watch of 2020.
Tom Allen-Stevens 30 Research Briefing - Emerging from the shadows
Technical editor Research shows folpet may be more effective than previously thought.
Lucy de la Pasture 34 Real Results Pioneers - Dig down to preserve potential
Machinery editor One Cambs grower resolved to get a better understanding of the soil.
Charlotte Cunningham 38 BioScience insider - Primed for defence
Writers Innate defences against disease come at a hefty price to the plants.
Mike Abram Rob Jones 42 Fertiliser advice - Keep the faith
Things may be looking up for growers who kept their faith in the crop.
Tom Allen-Stevens Lucy de la Pasture
Charlotte Cunningham 44 Grow the future - The productive plus of a carbon conscience
A focus on climate change could add to your productivity.
Design and production
48 Technical survey - Inhibiting climate change?
Brooks Design Both the industry and the government are looking to reduce fertiliser emissions.
Advertisement co-ordinator
52 Fit for the future - When yield gives way to shield
Peter Walker Sow a seed you can depend on over one that may simply fill the barn.
Publisher
56 Consultations - Your views matter
Angus McKirdy Two significant consultations were launched in the New Year.
Business development manager
Charlotte Alexander
To claim two crop protection BASIS points, send an email to
Machinery
linda@basis-reg.co.uk, quoting reference CP/100659/2021/g.
62 Fertiliser spreaders - Precision pushes progress
To claim two NRoSO CPD points, please send your name, The capabilities of spreader technology have soared in recent years.
NRoSO member number, date of birth and postcode to
angus@cpm-magazine.co.uk 68 Innovation Delve - Trials uncover secrets to success
Claydon Drills and Hutchinsons have been carrying out cover crop trials.
*the claim ‘best read specialist arable journal’ is based
on independent reader research conducted by 72 On Farm Opinion - Going to great lengths
McCormack Media 2020 The value of low-disturbance kit is rapidly gaining traction in UK agriculture.
Editorial & advertising sales
CPM Ltd, 1 Canonbury, Shrewsbury, Shropshire SY3 7AG Innovation
Tel: (01743) 369707 E-mail: angus@cpm-magazine.co.uk
Reader registration hotline 01743 861122 77 Climate Change Champions - Regenerative route to Net Zero
The Southill Estate in Beds has productive soils that capture carbon.
Advertising copy 81 On-farm R&D - Field opens for agri-tech explorers
Brooks Design,
On-farm innovation is set to get the ELM scheme co-design treatment.
24 Claremont Hill, Shrewsbury, Shropshire SY1 1RD
Tel: (01743) 244403 E-mail: fred@brooksdesign.co.uk
CPM Volume 23 No 2. Editorial, advertising and sales offices are at Roots
CPM Ltd, 1 Canonbury, Shrewsbury, SY1 9NX England.
Tel: (01743) 369707. CPM is published eleven times a year by
CPM Ltd and is available free of charge to qualifying farmers
84 Potatoes - Understanding dynamics aids control
and farm managers in the United Kingdom. Nematodes and late blight are two of the big problems facing potato growers.
In no way does CPM Ltd endorse, notarise or concur with any of the 89 Sugar beet - Should neonics return?
advice, recommendations or prescriptions reported in the magazine. The granting of an emergency authorisation has attracted criticism.
If you are unsure about which recommendations to follow, please consult
a professional agronomist. Always read the label. Use pesticides safely.
CPM Ltd is not responsible for loss or damage to any unsolicited
material, including photographs.
crop production magazine february 2021 3
CPM (Print) ISSN 2753-9040 CPM (Online) ISSN 2753-9059
It’s never a good idea to ask a in the genome is pinpointed damaged or reclaimed soil?
plant root to grow through and marker-assisted How do they fair with cover
compacted soil, whether or breeding is used to bring crops, companion crops, in a
not it’s capable of doing the compaction-busting root blend, planted inter-row or as a
so. Organic farmers capability conventionally into perennial understorey? How
would rightly scorn a commercial lines. So it seems they do in min-till, no-till, strip-till,
system that engineered a little ludicrous to me to restrict controlled traffic farming, on sand
crops to allow bad a breeding technique that could that caps, or in deep subsoil
practice and such a effect the same change in a layers of naturally compacted
notion goes against the fraction of the time, whatever clay?
Root to success? very essence of conservation the outcome. Rather than restrict their
agriculture. The difficulty is that if you introduction to the field, that’s
So should we ban plant over-regulate a technique such exactly where these plants
Scientists have made an breeders and scientists from as GE because you fear it may should be. Rather than close our
important discovery about plant engineering such an ability into have undesirable outcomes, with minds to them, we should be
roots –– it’s not that they can’t crops? That is in effect how EU the same hand you stifle the open to what they can do, share
get through compacted soil, they regulation currently works, and potential for that same technique our views and build on one
choose not to. The question for the question Defra has now put to do good things. It’s not the another’s experiences
farmers is what to do with that in front of us in a consultation is fault of the tool that there’s a bad –– good and bad. And rather
information. whether to diverge from this outcome, but the way it’s used. than view them as a binary tool
The findings of the research, (see page 56). So rather than over-regulate and that will simplify a system, allow
led by Nottingham University, Defra has always believed that restrict its use, we should bring it them to find their place in
were published in Science last where a change to a plant’s DNA into the field and develop our a matrix of methods that
month. Compacted soil causes could have happened naturally, understanding. complements the rest.
ethylene to build up, according to this should not make it a GMO, Coming back to this discovery Here in the UK, right now,
the research team, which acts as subject to the tight EU about compaction-busting plant we are in a unique position to
a signal to plant roots to stop regulations. The grey area is roots, I don’t think we should unshackle ourselves from the
growing. But in plants where a gene-editing (GE) where a cut regulate or restrict breeding traditional view of how farming
mutation has been introduced to –– or edit –– is made at a very of plants that have this ability, should be done. We have a new
switch off this response, the roots precise point in the genome. The although I thoroughly respect the agricultural policy to put in place,
will continue to grow through the slight mutation that results when views of those who’d choose not and there is a genuine call
compacted soil. the plant naturally mends this cut to have them on their farm. from Defra that this should be
On the one hand, this is known to confer a desired trait. Equally, whether they choose to co-designed with farmers.
is potentially a massive Similar mutations happen grow compaction-busting crops The roadmap to its new R&D
breakthrough. Increasingly heavy every day in the field –– it’s the or not, the farmers who throw the Innovation package starts this
kit has put arable soils worldwide skill of the breeder that spots the good soil management rulebook spring (see page 81). This is
under pressure –– more than traits they confer and brings the out the window are fools. surely the time to bring as many
half of Europe’s 68M hectares desirable ones into commercial But there is a third way. technologies as we can into the
of cultivated land is prone to lines. In fact, it’s quite likely As with any crop bred with new field to explore what they can do.
compaction. Farmers spend a there’s a wheat plant somewhere plant-breeding techniques, these
fortune alleviating the problem with a natural mutation that’s are not tools for fools but plants
and yields could be significantly switched off this rooting with potential. Wouldn’t you Tom Allen-Stevens has a
improved if crops could be bred response. It could be in your want to know how they 170ha arable farm in Oxon,
that didn’t have this restriction. field and you’re just not aware performed in dry soils, brashy where the main restriction
But on the other, isn’t this that the mutation’s there. soils, late-planted after roots, in on roots is the inability to
exactly the wrong thing to do with Now that the trait has been the corner of that field where get into the field to start
this discovery? Compaction is identified, though, and scientists establishment is always tricky? them off.
damage to the soil, causing have a proof of concept from an Are they best used rotationally, tom@cpm-magazine.co.uk
soil erosion and nitrous oxide engineered plant, it’s just a or as a short-term measure @tomallenstevens
emissions, as well as poor yields. matter of time before the place to restore life and structure to a
that clearly forbids any sniff of crop then doubled in recent years. I disturb as I trudge across the
production. At the other end of the Although the effect of schemes crop, it’s good for biodiversity,
spectrum there was our fields in that preclude production will have (and of course the bloody
archaeology protection different impacts on different pigeons!)
schemes that precluded the farms, you could argue there is a Then there’s the benefits of
use of plough but otherwise deleterious impact on our industry over-wintering OSR crops in terms
allowed crops to be grown as a whole if you downsize of the boon they provide to
however you thought fit. production. Things like R&D insects in early spring as a rich
For us as a business, the budgets and infrastructure source of pollen, not to mention
attractiveness of the schemes investment depend on the nesting habitats for reed buntings
was more to do with the level of critical mass of their economic in early summer.
Covering all bases payment rather than whether they foundation. I don’t suppose there is a
permitted arable production but There is also the snowflake’s chance in Hell that
One of the key questions to be we were conscious that there are much-discussed chestnut of Defra would ever accept winter
asked of the new Environmental efficiencies of fixed costs achieved our food self-sufficiency as a OSR as eligible for an acreage
Land Management (ELM) through economies of scale to nation. Without going into this payment under an environment
Scheme is to what extent it will consider. Once you start reducing vast discussion in detail, the scheme but nonetheless maybe
be dominated by elements that a cropped area to less than simple fact is if we produce less we should be making the case.
take land out of crop production. 300-400ha then fixed costs start to food as a nation and consumption If it requires some sort of min-till,
We’ve had some personal increase at a greater rate than on a patterns remain the same then we non-plough condition then all the
experience of this over the years pro rata basis. When it comes to will import more from abroad. This better. On our land in the typically
with our involvement with various the key issue of payment rates the will in turn have important impacts dry autumn it’s almost impossible
environment schemes. At the one term ‘income foregone’ becomes on our economy and on the to get good tight seedbeds for
end of the scale there is our all the more electric when wheat environments of those places small seeds behind the plough
arable reversion rough grassland prices have more or less halved that make up the shortfall. anyway. So it would be a win for
There are also important my bank account and the ecology
cultural issues. For right or wrong of my farm not to mention the
farmers are by definition active nation’s food security and balance
food producers rather than of payments. What’s not to like?
passive park keepers.
So there is a case for coming Pigeons may be unwelcome in
up with imaginative environment OSR, but is the crop delivering
schemes that allow production a host of ecosystem services?
rather than preclude it. I was
chewing this over in my mind as
I trudged through my oilseed rape
crops on my winter morning ritual
of checking for pigeons and test
firing the bangers.
The OSR is notably proud this
year having thrived in the wet and
warm autumn. Although some
agronomists, with good reason,
will worry about over-proud OSR
crops, in another analysis it
should be seen as a good cover Guy Smith grows 500ha of
crop providing all sorts of other combinable crops on the north
benefits. It’s fixing nutrients, so east Essex coast, namely
they don’t wash away in what is St. Osyth Marsh –– officially the
driest spot in the British Isles.
proving a very wet winter. Very
Despite spurious claims from
importantly it’s absorbing and others that their farms are
fixing carbon. Furthermore it’s actually drier, he points out
conditioning the soil with its that his farm is in the Guinness
vigorous rooting, and by providing Book of Records, whereas
a cover, protecting against others aren’t. End of.
erosion. Finally, judging by the @essexpeasant
linnets, hares and skylarks
6 crop production magazine february 2021
Thinking differently
about weeds
“ Use little
hammers and not
sledgehammers.
”
Technical
Weed management
You don’t have to be Einstein modes of action (MoA) available in an periods, which means they can grow
international survey published last year. rapidly in the periods between times
to know that doing the “There’s a real risk that we may run out when effective controls can be applied.
same thing and expecting of chemistry to control some weeds. “Intensive weed control can degrade
Resistance is expensive, with the annual farmland’s natural capital, with potential
a different result is the cost of blackgrass resistance in England negative effects on both farm productivity
definition of insanity. Is it estimated at £0.4bn in lost gross profit and the environment,” believes Chloe.
(2014 prices) to the industry. According to Regular and intensive tillage is a major
time to look at managing research published in the scientific journal contributor to unsustainable levels of soil
weeds in a different light? Nature Sustainability, in winter wheat the erosion, she adds. “In Europe, soil erosion
cost of herbicides can be anything rates are from 3-40 times more than the
CPM reports. between £75-450/ha for blackgrass control. upper limit of tolerable soil erosion. Both
tillage and herbicides have some effect ▲
By Lucy de la Pasture Evolving resistance
“The more we study the problem, the
tricker it seems to be getting. We used to
Blackgrass has become a weed that’s think that if you mixed herbicide MoAs then
driving farming strategies on many it would prevent resistance, then as time
farms –– its success and the failure of went on it was realised resistance was
herbicide measures has led to changes still evolving. Recent research from
in rotations, cultivations and herbicide Rothamsted, led by David Comont, is
use. But instead of a weed being the showing that mixing herbicides does delay
force behind changes in practice, could target site resistance, but at the same
weeds be thought about in a different time it also promotes the development
way and be managed more ecologically? of cross-resistance,” she explains.
That was the question posed by Chloe also points out that more
Dr Chloe MacLaren, plant ecologist at intensive weed control can select for more
Rothamsted Research, during AHDB’s problematic weeds. On a farming systems
Agronomy Week. level, weeds which are generally tolerant or
Chloe points out that the way weeds good at avoiding control are becoming Chloe MacLaren believes the time has come for
are being managed across the globe is increasingly common. “These weeds new thinking about weeds and particularly the
a struggle, with 262 weed species found achieve this through strategies such as benefits diversity can bring.
to be resistant to 23 of the 26 herbicide variable germination times or short growth
8 crop production magazine february 2021
Weed management
that the weeds will always win. We need
new ways of thinking about weeds,” she
says. Foremost Chloe suggests it’s not
necessary to get rid of all weeds and that
instead the aim should be for farms to be
more resilient to problematic weeds.
Diverse community
“We don’t want huge populations of
species like blackgrass, but we do want to
foster a diverse community of wild plants
Intensive use of herbicides selects for weeds with so that the weed benefits outweigh the
a similar growth habit, metabolism and resource costs of having them there,” she says.
requirement as the crop itself, hence the success “Amongst the positive functions of weeds
of blackgrass as a weed. are soil protection, nutrient cycling and
interaction with beneficial insects ––
on soil microbes, particularly mycorrhizae. providing pest interference and pollinator
▲
“We don’t know enough about this yet support. Removing weeds habitually
to know if that contributes to a change or means all these functions can potentially Small, flowering weeds (or wild companion
loss in function of soil microbes, but it does be lost.” plants) such as field pansy can bring more
suggest we want to be careful about how Long-term research studies show that overall benefits than costs to farmland.
often we use either of these tools.” many weed species may not be as
The conventional approach to weed competitive with the crop as most people When plots with high diversity
control is also a major cause of biodiversity think, she adds. “Weed diversity is (~20 species) were left unsprayed, the
loss in farmland –– critically bird biodiversity associated with reduced competition yield loss caused by the weeds was
depends on the variety of weed seeds that between weeds and the crop. There is much less than in plots with low diversity
are available, she highlights. evidence for this in Rothamsted’s long-term (5-6 species): 30% compared with 65-80%.
“Several arable weeds are being farmed Broadbalk experiment, where researchers A further long-term study in France
to extinction but we’re still losing the war on compared plots with high weed diversity to published in Nature Sustainability looked at
weeds. The more we study them, it seems plots with low weed diversity. the effect of different cropping systemsWeed management
and found different weed communities enhanced weed diversity.”
developed in each system over time in Chloe suggests that the question in
response to the management used. In agronomist’s and farmer’s minds shouldn’t
unweeded and zero weeded plots the be ‘how weedy is the field?’, but more
researchers found six distinct weed ‘which weeds are there and how many
communities, four of which decreased different species are present?’ when
yields (20-55%) but two had no effect making weed control decisions.
on yields. “Weeds which are beneficial in
“The yield loss was also less as weed crops are small, slow-growing, mainly
diversity increased. The study found large-seeded flowering plants. These
yield wasn’t strongly correlated to are less competitive with the crop while
weed density but was highest in weed providing more services to biodiversity.
communities dominated by blackgrass Tall, fast-growing, competitive weeds
and cleavers, and lowest where field –– such as blackgrass and wild oats
pansy or speedwell were present with –– aren’t desirable,” she explains.
Putting the theory into practice is tricky,
and solutions will be specific to farming
systems and sites, admits Chloe. But there
are a number of things to avoid, she says. Steve Cook says agronomists are having to use
some pretty big sledgehammers, particularly to
Eliminating weeds tackle blackgrass.
“Firstly, try to avoid consistently
penalising weeds for being different to in selecting for weeds that are similar
the crop. Examples of this are always to the crop and benefit from the same
eliminating weeds that germinate before resources, so are more competitive in
the crop, disadvantaging weeds that use nature.
alternative resources or are more stress “Secondly, avoid doing the same
Flowering weeds provide seed for birds and an
tolerant or using in-crop herbicides that thing each year as this exacerbates the
interaction with beneficial insects – providing
eliminate weeds that have different problem of selection for similar and more
pest interference and pollinator support.
metabolisms of growth forms. This results competitive weeds. Then, if possible, try
▲Weed management
frequencies and precision application of
herbicides.
“Minimising resource ability means
limiting light, nutrients and water to weeds.
Not only do more free resources mean
more weeds, but high resource availability
helps fast-growing problematic weeds in
particular.
“This can be avoided by choosing
competitive crops, using precision
techniques such as variable rate fertiliser
applications and drip irrigation, and/or
choosing organic nutrient sources
(legumes and manures) that release Campus OSR was successfully established
nutrients more slowly. Light to weeds can on David Miller’s farm this autumn with a
also be limited by shading the soil with multi-species companion crop, with no need
intercrops, crop residues and mulches,” for insecticide or early herbicide treatments.
she explains.
If those three principles are followed, David Miller of Wheatsheaf Farming
David Miller has embraced change on his farm, Chloe is optimistic that the last principle, Company in Hampshire is one of these.
which now has a focus on agroecological ‘take advantage of the positive aspects of He’s adapted his farming system to
principles. weeds’, will come naturally. “Increasing improve soil health and reduce dependency
diversity, avoiding sledgehammers and on inputs on his 700ha of Grade 3 ground.
not to create an environment where reducing resource ability should lead us “Herbicides were developed after World
▲
the only worry the weed has is resisting toward farming systems that are resilient War 2 with the intention of being used in
control. to problematic weeds whilst allowing a conjunction with cultural controls. Weed
In intensive systems with short-strawed diversity of less competitive wild plants control has now become a reactive system
cereals, high fertilisation rates and to persist. These remaining ‘weeds’ (in which relies on applying herbicides.”
pesticide use, this means that weeds this case perhaps better termed ‘wild David moved to no-till six years ago and
face little competition and few enemies or companion plants’) will then contribute uses cover crops extensively to bridge the
pathogens –– meaning the only selection to soil quality and supporting beneficial gap between cash crops on the farm. In
pressure is herbicides.” biodiversity,” she comments. this time he’s already seeing a significant
To manage weeds in a more ecologically reduction in blackgrass and a shift in the
sound way there are four main principles, Enhancing biodiversity weed species present, with less-competitive
says Chloe. “Increase diversity in all Agronomist Steve Cook of Hampshire weeds becoming more prevalent.
its forms, use little hammers and not Arable Systems says that enhancing Companion crops also feature heavily in
sledgehammers, minimise resource biodiversity probably comes low on the list his system. This autumn, oilseed rape was
availability and take advantage of the of priorities for most agronomists, whose drilled with a mixture of vetch, berseem
positive effects of weeds. All of these are main aims are to avoid yield losses and and crimson clover and buckwheat and
useful for pest-pathogen management optimise grower margins. established successfully without the use
and nutrient-use efficiency,” she explains. But he also says that weed problems of any herbicides or insecticides. After a
“Increasing diversity in all its forms have built up in recent years. “Agronomists good frost has thinned out some of the
refers to increasing crop and management are having to use some pretty big more susceptible companion plants,
diversity –– in rotations and in different sledgehammers and pushing things David removes the rest using Astrokerb
fields –– to avoid creating a consistent too hard, but they’ve had to tackle (propyzamide+ aminopyralid).
environment where well-adapted weeds blackgrass.” All the spring-cropped land on the farm
can proliferate. He puts part of the problem down to benefits from a mixed-species cover of
“Increasing other forms of biodiversity –– poorer rotations which have reduced crop sunflowers, vetch, lupins, camelina,
whether farmed (such as livestock) or wild biodiversity but has also observed that berseem and crimson clover and buck-
(such as seed-predating insects) –– can farmers seem to have a reduced tolerance wheat over the winter. ““There’s a natural
also help to suppress weeds. The use of of weeds in their crops than perhaps they sequence of senescence in the mix and
‘little hammers rather than sledgehammers’ did several years ago. we use a Cambridge roll when conditions
encourage tactics that target just a few Steve believes that there are good are frosty in Jan to bruise the remaining
species at specific times and places, while reasons behind the desire for clean crops, crop, enhancing die-back,” he says.
allowing beneficial species to persist.“ including ease and speed of harvest and Nitrogen use is one of the factors David
Chloe gives the example of using little that even though in theory it should be is looking very closely at in his farming
hammers in practice. These are techniques possible to leave behind the less system. “The last tonne of yield can require
such as intercrops and cover crops, rather competitive weeds, in practice herbicide 100kgN/ha and when you consider the
than sprayed or tilled inter-rows or fallows; actives are mostly broad spectrum, even negative side of nitrogen application, what
using mowing or weed wipers to target tall in spring. it does to the soil and weeds, then you
competitive weeds, while leaving short But more and more growers are finding have to question whether the extra yield
species untouched; using reduced tillage that where there’s a will, there’s a way and is worth it.” ■
12 crop production magazine february 2021“ Most wild
oat plants are only
resistant to one mode
of action
”
Herbicide hints
for spring
Technical
Weed management
February sees many
A fatua, 10% A. sterilis spp. ludoviciana and
agronomists getting ahead of 21% were a mixture of both species. It was
the spring rush and noting a higher proportion of winter wild oat than
we’d anticipated –– it had been assumed
weeds which may need to comprise around 10% of the population,
attention as winter turns concentrated in a central band across
the country.”
into spring. CPM finds out the Questionnaire responses suggest that
latest on wild oat resistance, farmers and advisors consider the wild oat
problem to be increasing at the highest rate
some spring advice for where winter wild oats are present, making
blackgrass and a farmer’s understanding the contrast between the
two species important, says John.
strategy for getting ahead John Cussans says the survey showed a higher
of weeds in peas. Herbicide resistance proportion of winter wild oats in the population
“The immediate concern is that the than previously thought.
By Lucy de la Pasture prevalence of herbicide resistance might be
higher in winter wild oats compared with the confined to one area.
and Rob Jones spring wild oats and that this may be behind Where wild oats have shown regrowth in
the former’s increased abundance.” the field and have been sent to NIAB for
Wild oats have taken a bit of a back seat To test whether this was the case NIAB testing, the resistance between species
as the spotlight has been shining firmly went on to test seedling susceptibility begins to diverge more, he adds. “In these
on blackgrass in recent years. to Axial Pro (pinoxaden) and Niantic samples 10-15% of spring wild oats and
“They’ve gone under the radar and (iodosulfuron+ mesosulfuron) at field rates. 30% of winter wild oats have shown
we haven’t looked at updating our The initial findings point to cases of resistance to ALS herbicides.”
understanding of wild oats for many years,” resistance in both species to both classes There are some features of wild oat
says NIAB weed biology specialist John of chemistry. biology that mean resistance takes much
▲
Cussans. “We felt it was really time to “10-15% of seedlings tested showed
provide an updated picture of wild oat resistance to pinoxaden. Where ALS
herbicide resistance, and also a general chemistry was used, 5-10% of spring wild
picture of where we are with wild oats oats showed resistant compared with
currently across the UK.” 10-15% of winter wild oats. Fully resistant
To achieve this, NIAB teamed up with Life wild oats were seen but decreased
Scientific to carry out the first survey of the sensitivity to the ALS herbicide was also
wild oat population in more than 20 years. detected which means a lack of herbicide
In excess of 100 samples were received at robustness may be seen in the field rather
NIAB and speciated to find the relative than incomplete control,” says John.
proportions of the UK’s two wild oats –– Even though the resistance was found
The UK’s two wild oat species are only
Avena fatua (common or spring wild oat) at a relatively low level, John believes it’s
distinguishable by their seeds –– the spring
and Avena sterilis ssp. ludoviciana (winter significant that resistance was detected
wild oat has a single seed whereas the winter
wild oat), he explains. across all the areas the samples came
wild oat has two-three seeds within a glume.
“70% of the samples received were from, indicating that the problem isn’t just
14 crop production magazine february 2021Weed management
Darren Adkins says that where pre-emergence
sprays were applied, blackgrass control looks
reasonable.
oats are hexaploid, meaning a plant has
three pairs of chromosomes where
blackgrass has just one, it develops
resistance much more slowly but once
developed, resistance will dominate,”
warns John. Fields that didn’t receive a pre-emergence
herbicide will benefit from a post-emergence
Metabolic changes spray when conditions allow to reduce
“ALS-resistance is mainly metabolic whereas competition from blackgrass.
resistance to fops, dims and dens is
mostly target site, with some involvement of Looking globally, in the North of North
metabolic changes. Wild oats have a more America wild oats have become problematic
complicated cross-resistance mechanism on the same scale as blackgrass is in the
than blackgrass and also have more fop UK, with resistance to a wide range of
and dim-specific mutations than to den herbicides, says John. “The potential is there
chemistry. Most wild oat plants are only for a problem to develop in the UK if the
resistant to one mode of action and there wild oat population isn’t understood and
longer to build than in blackgrass. “Wild is little cross-resistance, so rotating actives managed appropriately. It’s not possible to
▲
|oats are in-crossing (selfing), so the pollen is a good strategy for wild oat control,” collectively manage all grassweeds under a
doesn’t spread out in the field. Because wild he explains. strategy designed to control blackgrass.” ■
Getting the best out of blackgrass post-ems
Despite a wet Oct, farmers successfully drilled and 50% on the application is a good guide.”
most of their planned wheat area but not all For contact-acting herbicides, application
crops received a timely pre-emergence herbicide, technique and conditions are crucial to getting
so some fields may benefit from a follow up the best grassweed control, says David, though
this spring, according to Darren Adkins, he emphasises that any application involves
Bayer commercial technical manager for compromise.
theEast Midlands. “There are so many variables when spraying
“The settled spell at the start of Nov meant that conditions will never be perfect. The thing to
that most wheat went in this season. Farmers aim for is to get as many things right as possible.
understandably prioritised drilling rather than “On our own farm, we managed to apply
pre-ems but, where they were used, control looks post-ems in the autumn where they were needed,
reasonable.” so we won’t go back out this spring. With
Reducing blackgrass levels in the spring helps blackgrass, the principle for all contact-acting
reduce seed return and blackgrass problems in herbicides is that if the target is there and you can
future crops but it’s not the only weed to consider, spray, then get it done because smaller plants are David Felce stresses that getting the application
with other grassweeds and broadleaf weeds more susceptible. The date doesn’t matter (label right is as important as herbicide choice.
also providing competition in some crops, allowing) as long as conditions are in your favour.”
suggest Darren. For products like Pacifica Plus, active growth doesn’t have the weight to fall and adhere to the
“There’s often a mixture of weeds to deal with and sufficient drying time, ideally with a light target. Air induction nozzles reduce drift and will
in spring, which is why we introduced Pacifica Plus breeze, are the most important considerations allow more spraying opportunities but be aware of
(mesosulfuron+ iodosulfuron+ amidosulfuron) last in early spring. Without these, the herbicide is target and droplet size.”
year. It controls grassweeds like its predecessor, unlikely to be effective as it won’t be taken up by Any spray windows are likely to be short at this
Pacifica but the amidosulfuron component also the weed plant in sufficient quantities to kill it, time of year, but water volumes are one way to
adds broadleaf weeds to help clean up the crop adds Darren. increase area sprayed. “In open crops 100 l/ha is
in one application before moving on to other If conditions are favourable, then sprayer set up sufficient to get good coverage. As the canopy
spring jobs.” is the next focus. Droplet size and distribution both develops during spring this will have to increase
Spray application specialist David Felce, Agrii depend on nozzle choice and operation, explains to 150 l/ha or 200 l/ha.”
regional technical adviser and Cambridgeshire David. “In open crops in early spring, I favour a 03 Later in the spring, nozzles with a larger
farmer, recommends paying close attention when flat fan nozzle as it produces a smaller droplet size droplet size will probably be needed to penetrate
applying post-ems in wheat this spring. with even distribution. This means the herbicide is the canopy and reach weeds beneath. For all
“Application is always hugely important for any likely to reach the target and settle on the leaf. applications, a boom height of 0.5m above the
crop protection product. We can argue over exactly “With this type of nozzle, you have to watch canopy is a good starting point although the
how much of a difference it makes, but the old forward speeds; too fast and the pressure technology on some modern sprayers can safely
saying that efficacy is 50% based on the product becomes too high, creating a fine spray that go lower, he adds.
16 crop production magazine february 2021Removing the competition
With limited post-em options for
chemical control of weeds in peas,
a pre-emergence tank mix is critical
to ensure the crop remains
competitive during establishment,
says Velcourt farm manager Tom
Macfarlane. He oversees the arable
enterprise at Bannister Farms,
near Boston in Lincolnshire, where
the spring break crop is a key
component in a varied rotation.
The rotation includes vining
peas, cereals, sugar beet,
vegetables and maincrop potatoes,
all grown on light alluvial silt.
Approximately 40ha of vining peas It’s important to get the
are harvested each season on pre-emergence spray right with
contract with Boston-based so few herbicide options once the
co-operative Fen Peas. As crop is up, says Tom Macfarlane.
well as its ability to fix nitrogen in
the soil which benefits following herbicide options once the crop
crops in the rotation, the crop helps is up,” he says. “Post-em
to spread the autumn workload on applications can also check the
the farm, says Tom. crop, which is the last thing you
“Our average vining pea yield is need when it has to battle with
4.4t/ha which provides a profitable some of the challenging weather
margin to the business. And while we’ve seen in the spring in
the following crop benefits are recent years.
difficult to quantify, there is Tom highlights the importance
definitely a yield benefit in either of seedbed preparation to give
wheat or potatoes which usually peas a good start. “Seedbeds
follow after vining peas in our must be clod-free, level and
rotation.” contain some moisture for
He says that the early harvest maximum residual herbicide
that comes with growing peas efficacy.”
provides a good opportunity to For crop safety, seed is placed
begin land preparations ahead of at a minimum depth of 2.5cm
an autumn-planted crop, when and the pre-em herbicide
conditions are at their optimum, application is made as soon as
and this helps spread the farm’s possible after drilling. Typically the
overall workload. mainstay treatment includes
This year is a case in point, 3.0 l/ha Nirvana (imazamox+
where some drainage work will be pendimethalin) and 0.25 l/ha
completed on land after peas have Centium (clomazone) in a
been harvested and before the tank mix.
subsequent autumn crop is drilled. “We’ve always included
And being a spring break crop, Centium to give us good control
peas also provide further of cleavers, but it also helps with
opportunities to control grass control of chickweed, red
weeds, he adds. dead-nettle and shepherd’s purse.
With thoughts turning to crop It was noticeable in spring 2020,
establishment in 2021, Tom says when it was drier than I would
that a range of broadleaf weeds have liked when we applied the
including polygonums and cleavers pre-em, that we still achieved
are his main targets each spring to good control of these weeds.
ensure the pea crop gets off to the “Getting this aspect of weed
best possible start. control right, avoids the necessity
“It’s so important to get the for, and the risk associated with a
pre-em spray right with few post-em treatment,” he adds.Tests and tools with Bayer for James, as the lead in a group
of eight Sentry farmers. “For many years
to track and we’ve undertaken tramline trials with Bayer’s
Xpro club and a number of us wanted to get
involved with YEN. Bayer’s a key sponsor of
YEN, and offered to facilitate bringing us
trace together as a group and make the most of
what we get out of it.”
Now in its fifth year, the group gathers
twice a year –– just before harvest and
again in Nov or Dec, when they take a
close look at the YEN reports. The report
gives a full analysis of how the field in
question performed, as well as its
maximum potential yield, benchmarked
against other YEN farmers.
With a farm average wheat
yield of around 9.5t/ha, James’
“ You can’t
actually see any disease, ahave
YEN crop tends to perform at
middling 10.5-11t/ha. “We
had an 11.5t/ha crop of
so it’s useful to know Skyfall that achieved best
what’s there in its latent percentage of potential
yield in our group and 17th
phase.
” nationally,” reports James.
“But for me, it’s not about the
competition. That result opened my
eyes to what we could achieve off some
of our more variable soil, and as a group, it
really helps us focus on what improvements
we can make.”
The six-year rotation on the farm includes
Technical Forward- oilseed rape, peas, beans and winter and
spring barleys across its mainly chalky
thinking farmers boulder clays. “Our calcareous soils are
prone to nutrient lock-up, notably phosphate,
so we’re doing more tissue testing. In the
Decent diagnosis of in-field It’s the prospect of managing disease past year we’ve also joined YEN nutrition,
issues ensures the right with a reduced armoury that’s giving him bench-marking grain analyses to better
pause for thought, however. “We know we determine our offtake levels and overall
product is applied in the right have to stay in the protectant zone, and grain nutrition levels.”
place at the right time. CPM that’s rarely been a problem. But last While involvement with YEN is helping
spring we had chlorothalonil and disease James address nutrient issues, last year
reports on the progressive levels were very low. This year could be he also submitted samples for Bayer’s
growers and agronomists an entirely different animal, and we’re Rapid Disease Detection test for the first
facing it without CTL –– how will that time. James joins Bayer south east
▲
helping to refine the change things?”
techniques.
Key concern
By Tom Allen-Stevens Yellow rust has always been a key
concern. “But it’s a disease we know
how to manage. We never underestimate
James Mayes confesses he has a little septoria, though, and know the damage
trepidation for what the season holds a wet spring can do.”
for his wheat crop. This year there are a couple of extra
He manages 800ha of combinable tools in the armoury that James hopes will
crops for Sentry at Bentfield Bury Farms, help him though. He’s putting Bayer’s
near Stansted Mountfitchet, Essex. The Rapid Disease Detection service through
wheats are all Group 1 quality types with its paces and has also signed up to the Bentfield Bury Farms has had good results from
KWS Zyatt and Skyfall in the rotation, and free trial of Climate FieldView, Bayer’s Skyfall winter wheat, and this year are trying a
there’s one field grown as a blend of the digital platform. blend with KWS Zyatt.
two this year as a trial. It’s part of a long-standing relationship
18 crop production magazine february 2021Forward-thinking farmers
scenarios you could then act on
accordingly (see panel below).”
This year there’s a plan to use Rapid
Disease Detection to pick up any yellow
rust in the crop, as well as septoria, and
to use FieldView to inform decisions. This
was used with the Sentry team for the first
time last year, and the biomass maps the
digital platform generates can be useful to
direct in-field monitoring, Richard explains.
“It gives you a regular check of how the
crop is developing, and unlike other
platforms, the biomass map in FieldView
The Sentry group gathers twice a year – just before harvest and again in Nov or Dec, when they take a doesn’t saturate later in the season. That’ll
close look at the YEN reports. be a good guide for areas of the field
you’ll want to sample with Rapid Disease
commercial technical manager Richard discipline to get into the crop and look in Detection.”
▲
Prankerd in a Zoom call to discuss results more detail at what we’re facing as each So what about the field with the blend
and the plan for the coming season. spray timing approaches –– you pick up of Zyatt and Skyfall? “They complement
“We first started qPCR analysis seven other aspects that may need addressing,” each other well on septoria, but there’s
years ago to detect septoria DNA in wheat he notes. a potential issue on yellow rust,” says
leaves before symptoms show,” explains He chose a field of Zyatt, late-drilled in Richard. “The two varieties have quite
Richard. “This was used in internal trial Jan, and Oct-drilled Skyfall. “The Zyatt
crops to get a better picture of whether didn’t receive a T0 spray –– we went
fungicides were being applied in a straight in with the T1. The Skyfall had an
protectant or eradicant situation. early dose of tebuconazole with CTL. We
“We’ve now moved to a rapid test with were keen to know from the test whether
results coming back within 48 hrs, making that would make a difference, and then
it a practical in-season tool for growers to how disease would develop up to the
inform fungicide rates and choice at the T2 timing.”
main T1 and T2 spray timings.” In the end, there was very little disease
So five days before a planned at both timings, largely down to the lack
application last year, James collected of rainfall –– just 0.5mm was recorded on
around 20 of the top two leaves in the the farm throughout May. Richard reports
crop canopy and sent them in for analysis. a slightly higher level of septoria was
“You can’t actually see any disease, so found in the Zyatt, “but levels overall
The rapid test gives results within 48 hrs, making
it’s useful to know what’s there in its were so low it could just be background
it a practical in-season tool for growers to inform
latent phase,” says James. noise. In a normal season, you’d expect
fungicide decisions at the main spray timings.
“For us at Sentry, it’s also been a useful to see significant differences in these
DNA testing reveals how septoria surges
Just how quickly a septoria threat can develop Elation coming in at over 250 pp/µl and Motown
can be seen from the data Bayer has acquired not far behind.
via various diagnostic tools since 2014, For Richard, it highlights how quickly rain
explains Richard. events can change septoria severity. “Growers
“Most of the work has been undertaken at have an idea of risk based on variety and drilling
our septoria-prone site at Callow, Herefordshire. dates but they are unaware of the weather to
Unfortunately, the autumn of 2019 put paid to come. In 2019, the dry spring had kept septoria in
trials for the 2019/20 season but 2018/19 results the base of crops, and there was talk of cutting
were revealing.” rates at T2. But these results show if you have Testing of leaves in wheat at the Callow trial
In 2019, the level of septoria DNA jumped after background septoria it only needs a few rain site in 2019 showed the level of septoria DNA
a series of rain events in late May and early June events to kick it off.” jumped after a series of rain events in late May
–– until then, DNA measurements had barely The work has also shown the value of variety and early June.
registered. First assessments taken on leaf two in resilience. Richard believes this can add an extra
Elation, Motown and Sundance, just ahead of T2 ten days to a fungicide spray window, but it’s At 5.7 Trinity was the most susceptible to septoria
sprays on 24 May, revealed only untreated Elation dependent on drilling dates, winter weather and and some samples carried DNA levels twenty
carrying perceptible infection –– this being rain events ahead of key growth stages. times above that of Siskin. No variety is immune
under 10 pp/µl (picograms per billion). Further “In 2016 DNA testing of leaf two, just prior to septoria, but what varietal resilience offers is
assessments just ten days later showed a to T2, revealed big differences in septoria levels the chance to schedule sprayer rosters around
significant increase in septoria DNA with untreated between KWS Trinity, Revelation and KWS Siskin. crops at highest risk,” he says.
20 crop production magazine february 2021Forward-thinking farmers
growth habits and grain characteristics
Forward-thinking farmers tend to be similar. “I’m not too concerned
with yellow rust, although we know
With robotics, gene mapping and molecular diagnostic tools and evaluate different farming pathogen populations are evolving so
markers, digital technology and bio-chemistry strategies, coupled with exciting plant breeding I want to stay ahead of what’s happening
it is a dynamic time for anyone involved in and product development programmes. It will in the field,” he says.
agriculture. help us develop innovative solutions and “I hope the testing and analysis we do
Challenges lie ahead for UK agriculture, such services to assist farmers achieve profitable this year will help not just with disease,
as improving productivity while minimising its and sustainable agronomic practices. but how the crop develops and how we
environmental footprint. But farmers have always Despite the challenges facing UK agriculture can retain green leaf area. There’s no
had to deal with change, and adopt new ideas there is much to look forward to. substitute for late season rainfall, but the
and technology. This series of articles focuses on crop’s got off to a good start. With the right
Bayer is at the core of these agricultural how innovation and partnership management, informed by in-season
advances, working with farmers throughout the between farmer and industry testing, we should be able to achieve
UK and further afield to trial and develop new will help us face the future together. its maximum potential.”
● Growers interested in taking part in
similar growth, though, so it’ll be from where they’re grown alone.” the free trial of Climate FieldView should
interesting to see how they develop Having grown both varieties for three get in touch with their local Bayer
together and whether disease levels differ or four years, James is familiar with their representative. ■
Resistance testing reveals a weed worry
Growers have been advised to keep an eye on high background population nor the result of poor
blackgrass and especially ryegrass in winter cereal application.”
crops this spring. Ryegrass plants with a high level Kevin contacted Bayer commercial technical
of resistance to residual herbicides have been manager Ben Giles who sent seed samples for
identified through testing. testing in Germany in July 2018. “They came
Bayer has been working with individual growers back as RRR resistant to both PDM and Liberator
and agronomists, investigating instances of (flufenacet+ DFF), and that’s really worrying,”
suspiciously poor control from autumn-applied says Ben.
residual herbicides, and helping with testing where Further work by Bayer as part of a
necessary. One of the first confirmed instance of pan-European study has shown the sample had
resistance in the UK was spotted by ProCam an ED90 (the level of active ingredient required for With few cultural options to control resistant
agronomist Kevin Pearcy, who looks after crops 90% control) for flufenacet of 800g/ha. “That’ll ryegrass Kevin Pearcy advises taking the
in Essex, Herts, Bucks and Glos. mean the typical field rate of 240g/ha will give affected areas out of crop production.
“We have pockets of bad ryegrass where very poor control,” he adds.
resistance to contact herbicides has already been Ben stresses that only a few instances of ryegrass species are very tough to manage.
confirmed, and here we rely on programmes pre-em resistance in ryegrass have been “If you suspect resistance, get samples tested,
based around flufenacet, diflufenican and confirmed in the UK. “We haven’t yet identified a although not all tests are based on the pot-test
pendimethalin with prosulfocarb and triallate case of blackgrass resistance, although reduced method which gives the best result for residual
added where necessary,” he explains. sensitivity has been confirmed through testing. In herbicides,” he advises.
“What was concerning was poor control from a these cases a well applied full rate of herbicide While reduced susceptibility to glyphosate
pre-emergence application. We needed to be sure will still deliver good levels of control.” has been confirmed in blackgrass, no cases of
this was truly poor control, and not survivors of a But Kevin notes that ryegrass can be more resistance in grassweeds have yet been identified
tricky to control than blackgrass with less effective in the UK. In bromes, instances of resistance to
cultural options. “It germinates all year round, and ALS and ACCase herbicides have been confirmed,
populations aren’t knocked back as much by a but no cases of resistance to residual chemistry
double spring break or a two-year grass ley,” have been recorded.
he points out.
“If you know the ryegrass population is
resistant to residual chemistry, I would advise
taking the affected areas out of crop production
through either a mid-tier option in Countryside
Stewardship, or preparing to adopt an ELM
option.”
Ben notes the importance of good hygiene to
stop resistant seed spreading. “The key one is
Ben Giles recommends those who suspect where you import straw that’s then spread with Ryegrass plants with a high level of resistance
resistance to get samples tested, ensuring muck, or transfer through contractors. It’s to residual herbicides have been identified
this is based on the pot-test method. important machinery is cleaned down between through testing.
farms. The lesson from Australia is that resistant
crop production magazine february 2021 21“ Lowering
inputs is just a
part of the
equation.
”
Can less
be more?
Looking across at his office wall, Brian and not just a crop in isolation, lowering
Barker scans the pieces of paper pinned inputs is just a part of the equation,”
there to give him inspiration. He settles explains Brian.
on the one carrying the quote, “That’s the One of his mantras is ‘farming for
way we’ve always done it, should we be potential not for hope’ and he religiously
doing it?” As a result of the trials being monitors every crop’s potential by monitoring
carried out on his farm, the pioneer in the biomass at key growth stages. It’s become
AHDB’s Strategic Cereal Farm network, an integral part of his farming practice and
the answer is, more often than not, Brian believes he now has a pretty good
a ‘No’. handle on crop potential from his five
AHDB’s Teresa Meadows explains that years of intense assessments. Even so,
the purpose of the Strategic Farms is he still gets a little twitchy about how low
to put research into practice and help he can go with inputs.
▲
growers find the line between inputs and
outputs so net margin can be maximised
Improving productivity is within an IPM approach.
all about using inputs more “They provide a platform for discussions
and take farmers on a journey which
efficiently. At AHDB’s encourages them to start to question
Strategic Cereal Farm in things and look at how inputs can be
matched to variety, disease and the
Suffolk Brian Barker is season rather than simply taking a
looking at just how low he programmed approach,” she says.
Tailoring nitrogen according to potential
can go by tailoring his inputs began when the farm did its stint as an
to crop, disease levels and AHDB Monitor Farm, but its current
Strategic Farm East status is taking the
the weather. CPM finds study of inputs to a whole new level.
out more. “The question we’re trying to answer Using regular plant counts to assess biomass has
is whether we can apply less and still been instrumental in determining crop potential on
By Lucy de la Pasture maintain crop output and to do this we’re the farm.
looking at the farming system as a whole
22 crop production magazine february 2021You can also read
