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  1. Spraying off areas of crops affected by black-grass is a difficult call to make, but it is one that more growers are considering in the fight against this increasing problem.

    Midlands-based Hutchinsons-Cropwise agronomist Andrew Wright says concerns about the spread of black-grass further north and west across the UK, combined with disillusionment over the efficacy of products affected by herbicide resistance, means there is more acceptance of this zero-tolerance approach.

    Andrew Wright

    Assessing crops during January and February for black-grass that has survived autumn treatments is key to making an early decision that minimises the financial impact and allows more time to sow an alternative spring crop if required, he says.

    “It is a difficult decision to make and there’s no set black-grass population threshold to go by; it’s really down to individual growers.

    “Some will want to spray-off areas of crops at the first sign of any surviving black-grass, while others will persevere, especially in regions where good results can still be achieved with spring herbicides, such as parts of Derbyshire and west Nottinghamshire.”

    Where a spring herbicide is to be applied, Mr Wright favours products based on iodosulfuron-methyl-sodium and mesosulfuron-methyl.

    He acknowledges efficacy can be reduced where resistance is present, but correct application still delivers worthwhile control of black-grass and other key weed species, such as wild oats and brome.

    Spring crops account for 20-25% of the cropping in Mr Wright’s region and he urges anyone going down this route to follow a few simple steps to minimise the risk of stimulating a troublesome black-grass flush within the crop:

    •    Prepare seedbeds in the preceding autumn
    •    Spray-off with glyphosate in the spring once soil has warmed and black-grass has emerged – typically two weeks before drilling
    •    Avoid further soil disturbance before drilling
    •    Drill later in spring when soil is warm and crops can establish quickly
    •    Minimise soil disturbance at drilling – direct drill if possible
    •    Sow competitive crops at a high seed rate to outcompete black-grass e.g. spring barley, up to 400 seeds/m2.

    Mr Wright also says the importance of delayed autumn drilling combined with an effective pre-emergence strategy for effectively reducing black-grass numbers before winter has been clearly highlighted this season.

    “We’ve seen some excellent results where growers have drilled later – typically after mid-October up to the first week of November – into good seedbeds and have used an effective pre-emergence herbicide strategy that included tri-allate.

    “However, where crops have been drilled earlier than this and/or seedbeds have been more cloddy, you can find black-grass coming through in places.”

    Spring black-grass control tips

    •    Map problem areas now ready for treatment
    •    Apply post-ems early when weeds are small, but…
    •    Ensure weeds are actively growing
    •    Consider the wider spectrum of weed control available from post-ems beyond black-grass
    •    Don’t overlook any areas of poor autumn control
    •    Consider spraying-off areas of crops where surviving black-grass populations justify to prevent weeds from setting seed and multiplying further
    •    Re-drill areas with spring varieties where possible
    •    Minimise soil disturbance when drilling spring crops (5cm depth max).

  2. Farmers must be bold and take a “zero tolerance” approach to spring-emerging black-grass and populations that survived autumn control, urges Hutchinsons agronomist and Norfolk farmer Alex Wilcox.

    Although autumn control was generally very effective given favourable weather and soil conditions well into November, he warns that high dormancy means there is a continued risk of fresh black-grass emergence into the spring.

    Alex WIlcox in WInter Wheat Dec 2016

    Early treatment of small susceptible weeds is crucial, but growers must also ensure black-grass is actively growing to maximise efficacy of post-emergence chemistry, he says. This may require patience, especially when coming out of a cold spell.

    In winter wheat, Mr Wilcox favours using a full rate of an iodosulfuron-methyl-sodium + mesosulfuron-methyl-based product applied as soon as conditions are suitable. He also recommends including a water conditioning agent such as X-Change to enhance control.

    “Even where resistance to this chemistry is present in field populations, there will still be some black-grass control and there is added value from control of wild oats and a range of broad-leaved weeds.”

    Fields should be walked over winter to identify and map problem areas of black-grass ready for treatment, he advises. “There’s got to be a zero tolerance approach towards any patches of black-grass.”

    He acknowledges there is limited ability to control black-grass in oilseed rape into the spring, but insists it must be a cleaning crop to avoid stoking up future problems, which again means a no-tolerance approach.

    “If you haven’t achieved good control from propyzamide-based products then be brave and mark these areas out, spray them off and re-drill with a hybrid spring oilseed rape.”

    For those putting problem black-grass areas into spring cropping, Mr Wilcox says minimising soil disturbance at drilling is key to avoiding a flush of black-grass within the spring crop. Direct drilling can therefore produce good results.

    Where drill systems disturb more soil, he advises growers to focus on establishing a competitive crop as quickly as possible.

    “Delaying drilling until late March or early April when ground is warmer can work, but it isn’t always suitable especially if you’re disturbing more soil as it simply encourages a flush of black-grass at the same time.

    “You may be better drilling earlier at a higher seed rate when conditions are cooler and black-grass isn’t growing to ensure the crop is in the ground and ready to go as soon as it warms up.”

    Spring black-grass control tips:

    •    Map problem areas now ready for treatment
    •    Apply post-ems early when weeds are small, but…
    •    Ensure weeds are actively growing
    •    Don’t overlook any areas of poor autumn control
    •    Minimise soil disturbance when drilling spring crops (5cm depth max)
    •    Consider the wider spectrum of weed control available beyond black-grass.

  3. With spring fast approaching, what are the best options for spring sowing - will spring 2017 be comparable with that of 2016?

    The open autumn has meant that many growers have been able to delay planting their wheat and benefit from controlling early flushes of blackgrass.  However , we envisage continued growth in spring plantings compared to 2016, with some varieties of spring barley proving popular and demand now starting to outstrip supply, says David Bouch, Hutchinsons seed manager.

    David Bouch of Hutchinsons

    “There will be challenges for OSR growers where winter OSR crops have been lost. The total area lost is somewhat difficult to ascertain. Some estimates say in excess of 70,000 ha, but it is safe to say that the hectares entered have seen a significant decline, due to both lack of moisture at the time of establishment and also to flea beetle damage where crops did survive.”

    Spring barleys are the preferred option for those growers with black grass concerns, and there are many varieties that can be considered as viable options for this sector, he says.

    “Propino will undoubtedly be the most widely grown and in turn could find seed supplies tight. Of the newer varieties, there will be increased interest in both RGT Planet and also Laureate where higher yield potential, coupled with initial support from the malting industry, offers encouragement. Agronomically both varieties also offer the possibility for cleaner crops.”

     “KWS Irina offers opportunity in different markets and again demonstrates good untreated yield, coupled with very stiff straw. There will still be a place for Concerto and Odyssey which both have malting and distilling potential. Finally, in the west where feed barley and a need for straw are more pressing, then Kelim has been a consistent performer.”

    Spring drilling will increase in 2017

    “Spring wheats are very individual choices and if milling is the requirement there is little need to look further than Mulika - whilst out yielded by all the other spring varieties, it is the only variety to offer group one milling qualities. It also possesses OWBM resistance along with Belvoir. “

    “KWS Kilburn offers the greatest yield potential for growers looking to keep things simple in terms of storage, if hard wheats are already in the farm rotation.”

    Mr Bouch notes that there is the potential to see a growth in spring oilseed rape on the back of high market values for the crop at harvest 2017. “Varieties  Builder, Dodger and Doktrin can be considered as options. Hybrid has to be the choice, with the necessary vigour needed for successful establishment.”

    He believes linseed could also see some interest, as contract prices currently look more attractive than they have in recent seasons.

    “Peas and beans are likely to be in reasonably tight supply with yields from harvest 2016 being disappointing and therefore, for those growers who are looking to plant after failed OSR crops, there may be a need for early decision making to acquire varieties of choice. “

    “Beans will undoubtedly be Fuego, Fanfare and Vertigo as the standard bearers, but there will be some interest in the new variety Lynx that has the best downy mildew resistance of any variety currently available. “

    “The choice in peas - Prophet and Campus - offer both yield and quality as large blues, with Campus in particular having excellent standing ability to enhance its claims for consideration.”

    Mr Bouch warns that supplies of seed for several popular varieties are likely to run short, and advises  growers to act promptly  in order to  secure their most preferred options.


  4. A three year survey carried out by Cobb Agri in collaboration with Hutchinsons, has shown that sulphur levels in UK soils are continuing to drop to very low levels, and need addressing this spring if crops are to reach their full potential.

    Sulphur is an essential plant nutrient that is required for optimum crop yields and quality as it plays an important part in plant metabolism; sulphur is essential for the formation of plant proteins and amino acids. Recent declines in atmospheric sulphur concentrations (as a result of reduced industrial emissions) have led to sulphur deposition rates across the UK that are not enough to meet crop requirements.

    “We suspected that many of our soils were deficient and we wanted to gain a snapshot of how these levels were changing from season to season. We knew two years into the survey that we had issues with severely low levels of sulphur in our soils, and this additional third year of testing has confirmed that levels are continuing to drop,” says Andrew Goodinson, agronomist with Hutchinsons.

    “For the purposes of accuracy, we opted for grain testing as this is the most reliable method of measurement for sulphur, as tissue and soil testing can produce wildly fluctuating results.”

    “Over the three years we have tested over 500 samples and our concerns have been confirmed; sulphur levels are continuing to decrease in our soils, with no obvious geographical bias.”

    “If we take results from 2015 and 2016 specifically, and look at two separate farms that we surveyed the issue is very clear. One farm that was sampled showed an N:S ratios of 17:1 in 2015 which dropped to 12:1 in 2016, a similar story was recorded at a second site where the sulphur levels dropped from 15:1 in 2015 to 11:1 in 2016.

    Andrew Goodinson

    “These results improved as we increased the rate of SO3 applied. “

    Mr Goodinson puts down these decreasing levels to a range of climatic factors. “We know that atmospheric deposition of sulphur is less with lower sulphur dioxide emission, so there is less sulphur available to plants generally. Meanwhile, warmer temperatures last autumn have led to faster mineralisation of the nutrient, which followed by heavy rainfall resulted in the removal of sulphur as well as nitrogen, magnesium and potash from the rooting zone of crops.”

    “We have found that the standard recommendation of sulphur for winter wheat is 25-50kg/ha SO3 (RB209) is not enough to replace the low levels that we have identified in the survey,” says Jessica Smith of Cobb Agri who was closely involved in the testing.
    Sulphur is a mobile nutrient and autumn applications may move down the soil profile away from the root zone restricting the availability of this nutrient, so there can often be an issue to get the timing of application correct, spring applications are more effective, “she says.

    Mr Goodinson recommends planning ahead for sulphur applications in the spring. “Prevention is better than cure. “Sulphur must be applied to the soil at the right growth stage, we recommend applying it at the first and second pass of nitrogen. We would generally recommend the addition of 75kgs/ha of sulphur to winter wheat, and a 100kgs/ha of sulphur to oilseed rape.”

    “However it is important to recognise that for the best results, sulphur rates should be increased alongside nitrogen rates and this was another reason why a greater proportion of the results fell into the low category this year.”

    “For example in organic manures with low rates of nitrogen, the sulphur levels will most probably be adequate. However, in very hungry soils that need higher concentrations of nitrogen, the sulphur levels will need to be increased proportionately,” he says.

    “On one farm where liquid digestate was applied, the ratio was 11:8 compared to 13:8 where no digestate had been applied.”

    “It’s also worth remembering that spring crops are not as responsive to sulphur as with the shorter growing period they have less time for uptake. “

    Organic manures can supply useful amounts of sulphur, with the crop-available S supply varying according to manure type
    Liquid digestate 35m3/ha = 40kg SO3
    Poultry litter 5t/ha = 40kg SO3
    FYM 25t/ha = 60kg SO3

    Why is Sulphur important?

    • Sulphur and nitrogen deficiency can often be confused. Chlorosis (yellowing) occurs in the younger leaves first, when sulphur is deficient. When nitrogen is deficient it will be the older leaves to show initial signs. However even in the absence of visible symptoms, yields can be affected. A quick leave tissue test for Malate:Sulphur ratio can highlight any issues.

    • Baking experiments have shown that loaf volume increases significantly if the bread making wheat has been fed with the correct levels of sulphur. If the N:S ratio is higher than 16:1 bread quality and loaf volume is compromised.

    • Acrylamide is a processing contaminant that has been found in cooked food that is formed during high temperature cooking and processing of wheat. HGCA trials have shown that asparagine levels, and hence acrylamide formation, can increase if wheat is grown in sulphur deficient conditions.


  5. Avoid single species cover crops and tailor mixes to farm conditions and objectives to get the best results out of this much-hyped addition to arable rotations, say organisers of a new field-scale demonstration.

    Farmacy’s 60-acre Calcethorpe cover crop demonstration site at Glebe Farm near Louth on the Lincolnshire Wolds is evaluating a range of seed mixes and management techniques to give growers a practical insight into the reality of growing cover crops.

    The trials have already shown how selecting the right cover crop mix brings a host of benefits above and below ground and organisers expect to see clear yield benefits from improved soil structure and nutrition in the subsequent spring barley crop.

    Alice Cannon

    “You don’t have to spend a fortune on exotic mixes, but you do have to select species that will work for your situation,” says Market Rasen-based Farmacy agronomist Alice Cannon.

    “It is possible to establish an effective cover crop for £20-40/ha, which is half the cost of some mixes, and maybe lower if you’re able to home-save some seed, however there is a clear purpose to these crops and investing in the correct species is vital.”

    There are a number of reasons for sowing a cover crop (see below), but no single species or mix can achieve all of these benefits so growers must prioritise the main aims for specific field conditions, she says.

    “Once you’re clear what you want from the cover crop, select a mix that can achieve these results.”
    Cover crop benefits:

    • Improving soil health by providing food for soil fauna and flora
    • Better soil structure and natural aggregation from root and biomass growth
    • Adds fertility (nitrogen) and organic matter
    • Reduces leaching
    • Moisture retention (light soil)
    • Prevents erosion (wind and water)
    • Suppresses weeds
    • Dries soil from depth (heavy land)
    • Forage for livestock.

    Mixes show more resilience

    Miss Cannon urges growers to avoid single species cover crops and choose mixes based on at least three different options.

    “The resilience of cover crops to pests and diseases really improves when they’re used in a mix. The presence of other species ‘confuses’ pests, reduces the transfer of diseases and also spreads the risk of crop failure should a problem occur with one species.”

    This was clearly highlighted in the Calcethorpe trials this autumn where all single species plots of peas and vetch following vining peas were decimated by pea and bean weevil, whereas only minimal damage was seen in legumes sown as part of a mix. Similarly, oats suffered significantly more BYDV and crown rust where sown alone rather than in a mix.

    Mixing species also brings different attributes in terms of root growth and above-ground biomass production, Hutchinsons technical manager Dick Neale adds. Crops such as linseed and sunflower produce large fibrous root systems, while others like radish and mustard put down a larger tap root able to break compaction layers.

    “We’ve seen roots go down to at least 1m and in general I’d expect to see 50% more root growth than top growth in most crops, however this depends on the drilling date and establishment conditions.

    “Extremely dry conditions have seen some August drillings perform very poorly in 2016 while later sowings into moisture have flown out of the ground. The aim is to get a mix of roots in the ground, but the type of crop sown depends on what you want to achieve.

    “The cultivation benefits of cover crops can be significant, but you must be prepared to give them time to work, at least three years ideally.”
    Even within crops there is quite a variation in their characteristics and potential benefits, so it is worth seeking advice on the best option for your situation, Miss Cannon says.

    White mustard for example is fast to establish and produces more above-ground biomass than brown mustard, but stems have a tendency to turn “woody” post-flowering and nitrogen is less readily available to the following crop.

    White mustard may therefore be a better catch crop option where growers want a lot of biomass quickly but are prepared to wait a season for the nutritional release, whereas brown mustard may be preferred for a quick fertility boost in the following crop, she notes.

    Heavy versus light land options

    The most appropriate cover crop options vary considerably depending on soil type.

    On light, drought-prone land, such as Glebe Farm, spring moisture retention within the soil is a major draw of cover crops, Mr Neale says. Mixes should therefore include crops with dense fibrous root systems that bind soil together well and also have “flatter” top growth to cover the soil surface and retain moisture.

    Establishing cover crops 2

    The favoured mix in these trials is based on 57kg/ha spring oats, with 1kg/ha white mustard, 7kg/ha spring linseed, 38kg/ha spring beans and 33kg/ha spring peas.

    “On this land I’d expect an extra 0.5t/ha yield in the following spring barley crop from the extra moisture retention this cover crop delivers,” he notes.

    Conversely, on heavy land, especially where black-grass management is an issue, Mr Neale recommends species with deeper roots able to penetrate dense layers and dry soil from depth.

    Top growth should be more erect to allow light and air to reach the soil surface to stimulate black-grass germination and let land dry out in spring. Spring oats and linseed are particularly suited to this, he adds.

    Destruction timing is key

    Desiccation timing is critical to get the best results from cover crops and the optimum will vary for every site, Mr Neale says.
    Generally, cover crops on light land can be sprayed off with glyphosate closer to drilling than those on heavy land.

    The moisture held in the top growth and roots within the seeding zone is an asset to the new crop on drought-prone land, whereas on heavier soils earlier termination of the cover crop – typically at least six weeks before drilling - allows more time for surface layers to dry out, he explains.

    Again species mix is key in relation to the “exit” strategy. Oats or rye must be sprayed or grazed off at least five weeks ahead of a following spring cereal, regardless of soil type, because they produce negative allelopathy and will cause a delay in growth.

    If top growth is to be retained, ask whether your drill can handle it? These issues should be planned for as you do not want to delay spring sowing of cereals or yield will be lost due to a lack of tillering time.

    Growers are reminded that EFA legislation requires eligible catch crop mixes to be established by 31 August and retained until at least 1 October, while cover crops must be established by 1 October and retained until 15 January.

    Find out more

    Two more free demonstration days are due to be held at the Calcethorpe cover crop site next year.

    In February there will be an event showcasing different termination methods for cover crops, while a separate drill demonstration day in March will examine how different drills cope with drilling into cover crops.

    Contact Alice Cannon ([email protected] – 07583 692576) for more information and to register your interest in attending.

    Tips for getting the most from cover crops:

    • Be clear of the reasons for using a cover crop
    • Avoid single species mixes – minimum of three different species
    • Tailor mixes to end goal and farm characteristics
    • Exotic and expensive mixes are not always best
    • Reduce costs by home-saving seed
    • Establish cover correctly – treat it like a crop
    • Time desiccation correctly according to soil type and following crop.