Arable
Consider take-all risk as early-drilled second wheats set to surge A combination of factors is pushing growers to consider planting more second or third cereals. Farmers Guide takes a look at the risks and how they can be mitigated ahead of the autumn drilling campaign. Is oilseed rape worth another shot? Or should I grow more wheat? Do I drill earlier to avoid being caught out by bad weather? These are all valid questions that growers might be asking when formulating cropping plans for this coming autumn. With strong prices, many will opt for more second wheat and if drill dates are brought forward, take-all risk will increase in many situations. This is leading many agronomists to advise the use of a Latitude seed treatment to protect yield.
“Of course, the final thing that might happen this year is that some will say: ‘To hell with late drilling’, because they can’t afford to get caught out again,” Mr Bean comments. “They will drill a week or so earlier than they might have done, to ensure they have a crop that earns them a margin. “All these factors will drag take-all into conversations, as risk is higher in early-drilled second wheats and although build up isn’t as severe after spring cereals, it is still a significant factor,” he adds.
Rotational disruption
Grower experience
It has been a difficult time for combinable crop producers over recent seasons, with extreme weather preventing a significant area of winter wheat being planted. On top of wheat woes, many have been forced into a reduced oilseed rape area or are walking away from the break crop altogether due to flea beetle pressure. Zantra agronomist Chris Bean (right), who advises growers across south east England, says many arable businesses have been moving away from second wheats too, put off by the additional risks and costs of getting crops to harvest in good shape. However, with rotations in disarray after two wet autumns and alternatives to oilseed rape less lucrative, he believes momentum has shifted again and more second wheat could be drilled this autumn, if conditions allow. The rotational disruption may also mean that a chunk of that wheat goes in after a couple of spring-sown cereals, where fields didn’t get drilled in the autumn or oilseed rape failed.
Mr Bean points out that not every farm or soil type will necessarily have a take-all problem, even where it might be expected if textbook logic is applied. He most often advises farms with lighter soils, which are known to be higher risk because they can be prone to drought. As the soil-borne fungus attacks the roots, symptoms are exacerbated once the land dries out and the crop becomes water stressed. There is also more space for take-all hyphae to spread and cause secondary infection in more porous soils. However, Mr Bean says on some farms with high-risk soils, growers may get away without any severe symptoms, while in similar situations a few miles down the road it can be a different story. “I’m not sure if that is down to variety choice or how soils are managed, but knowing field and farm history of take-all is an important part of decision making. “One thing we have been trying to do is grow varieties naturally suited to the second wheat slot. Milling wheat is widely grown in the south and Zyatt has done well for us,” shares Mr Bean.
Heavy land Bartholomews agronomist Justin Smith (right) agrees that take-all doesn’t always appear in the places where you most expect it, with severe symptoms seen on both the high-risk chalky downland and weald clays he oversees across Kent and Sussex. In the past two years, the heavy land has suffered from waterlogging, which has compromised rooting in his wheat crops. These wet periods were then followed by a dry spell in the spring – this has seen take-all have a significant impact as crops mature. “These blocks of extreme weather seem to be getting more common and it’s resulted in us seeing more take-all on heavier soils,” explains Mr Smith. Advising a number of mixed farmers, second wheat is an important crop for his clients and like Mr Bean, there will also be a significant chunk drilled after spring cereals this year, too. He says part of the integrated pest management strategy for take-all in second cereals includes attention to detail when preparing seedbeds to ensure they are well-structured and free from root-hindering compaction. Following that, later drilling should be considered, but he acknowledges the nervousness about delaying late into October, given the previous two wet autumns. On top of cultural reduction of risk, Mr Smith says he always raises the option of using a Latitude (silthiofam) seed treatment with his growers, as it is the only chemical seed treatment with take-all reduction on its label. Whether it is used ultimately comes down to whether the grower is willing to invest. “Some will not want to spend the money and gamble. In some seasons, you might get away with it, but those that have experienced 30–40 per cent yield loss from take-all now see it is a no-brainer. continued over…
10 www.farmersguide.co.uk August 2021
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