Variety choice will be a key starting point for high second wheat yields

UK wheat growing will intensify further in the coming season in response to favourable market prices, a benchmark national study of second-wheat management conducted this spring suggests.


The study conducted on behalf of Monsanto, involving 400-plus growers across the country bringing over 100,000ha of wheat to harvest this year, suggests the national wheat acreage is likely to grow only slightly in the coming season.


But within this it shows the area of second wheat set to increase by as much as 15%, as the wheat growing balance in rotations returns to the level it used to be before the poor prices of the past few years.


This will clearly put the onus on improved second-wheat agronomy to reduce the first to second wheat yield gap of between 0.5 and 1.5t/ha recorded by most growers, who overwhelmingly identify take-all as their biggest agronomic challenge (fig 1).


Figure 1


To address this challenge the vast majority of growers (more than 80% in each case) put their priority on selecting good second-wheat varieties and using a take-all seed treatment. Just over 70% delay drilling until October, with a similar proportion prioritising earlier spring nitrogen (fig 2).


Underlining the importance of an integrated approach to second-wheat agronomy, no less than 75% of growers prioritise both variety selection and take-all seed treatment, while over 40% employ all four key performance optimising techniques in their management.


“Second wheats can consistently deliver a handsome return on investment,” stresses David Langton of Masstock Smart Farming, which has set out the latest technical understanding for growers in a 20-page second wheat management guide as part of its Sustainable Rotations Initiative. “But only if they are managed correctly and in a different way from first wheats. Especially so with the level of input costs we’re seeing today.


“Our extensive research and development and Smart Farm work, the experience of our agronomists across the country and a number of valuable independent studies highlight the many things growers can do to make the most of second wheats. And we know that at least 50% of the important decisions are made before the crop emerges.


“With take-all and, to a lesser extent, eyespot the biggest challenges, correct variety choice is vital,” he points out. “As is appropriate seed treatment. Drilling date is another important consideration in minimising the impact of take-all, together with seed rate and doing everything possible to ensure the best root development.


“Alongside better crop nutrition and improved fungicide and growth regulator management, it is essential these measures are applied together as a package for the most consistent benefit.”


Masstock advises growers to select varieties that give both the highest actual yields as second wheats and have the highest yields relative to their first-wheat performance (see table).


While the particular yield potential of varieties like Oakley and JB Diego ensures they are near the top of the actual second-wheat yield list, their poor relative yields as second wheats casts doubt over their suitability for the slot in Mr Langton’s opinion.


Figure 2


In contrast, he reckons varieties like Duxford, Battalion, Sahara, Gladiator and Humber, which have high actual and relative second-wheat yields will be a more reliable choice. Whereas Einstein has been the benchmark second wheat for some while, Masstock agronomists’ recent experience backs-up trials evidence that it is becoming outclassed by these newer arrivals, several of which have particularly strong eyespot resistance.


“It’s worth remembering that milling wheats, which invariably tend to sit near the bottom of any yield ranking, can be particularly valuable as second wheats,” Mr Langton says. “After all, many growers use the yield limitation of second wheat cropping as a way of improving their chances of making the Group 1 spec by ensuring high protein levels.”


Regardless of variety, Masstock advocates using a seed treatment effective against take-all in second wheats as a matter of course this season unless the risk from the disease has historically been low.


“The specialist fungicide silthiofam (Latitude) is likely to be more valuable than either of the fluquinconazole-based dressings (Jockey or Galmano) where the take-all pressure is high,” he says. “Under these circumstances an average yield benefit of 0.7t/ha has been recorded in trial work, with associated improvements in specific weights of 1-2kg/hl.


“Where the take-all pressure is lighter, there is less to choose between the actives – both delivering yield benefits of 0.3-0.5 t/ha. With a yield improvement of just 0.15t/ha required to cover the cost of Latitude at this season’s prices, its cost:benefit is such that many growers may prefer to err on the side of safety and go for the specialist treatment. Where some early-season control of foliar diseases is considered important, though, the wider activity of fluquinconazole may be valuable.


“Regardless of whether you use a take-all seed treatment or not, the close correlation between drilling date and take-all impact always makes it advisable to sow second, third and fourth wheats last, giving priority to the first and continuous wheats that are at far less risk,” he recommends. “Indeed, I would never consider sowing a second wheat before October without an appropriate seed treatment.”


Unless sowing is particularly late or seed-beds difficult, the Masstock guide suggests there may be some take-all management benefit from reducing seed rates. As well as suffering lower levels of infection rates, crops drilled less densely tend to be better able to cope with take-all by virtue of their greater root mass. Equally, seed dressings will be more economic.


Well-prepared and well-consolidated seed-beds are also highlighted as important in both inhibiting early take-all development and encouraging maximum nutrient uptake and root proliferation.


Good nitrogen, potash, phosphate and manganese nutrition are particularly essential with second wheats, too, as is effective grass weed and volunteer control in the previous break crop. The use of suitable strobilurin fungicides and early plant growth regulation can also help.


“Undoubtedly the single most important ingredient for success with second wheat is the right attitude, though,” concludes Mr Langton. “More than anything else, the key to getting the best possible returns is to recognise the particular challenges the crop faces and do everything possible to overcome them.”


Fig 1: Biggest second wheat growing challenges


Source: Latitude National Second Wheat Management Study 2008


Fig 2: Priorities for second wheat agronomy


Source: Latitude National Second Wheat Management Study 2008


 





































































































































Mainline variety second wheat performance


Variety


Second wheat yield (t/ha)


Yield difference from first wheat (t/ha)


Duxford


10.29


– 0.71


Oakley


10.20


-1.18


JB Diego


10.20


-0.95


Battalion


10.14


-0.40


Sahara


10.10


-0.82


Istabraq


10.07


-0.86


Glasgow


10.05


-0.91


Humber


10.00


-0.82


Ambrosia


9.98


-0.80


Gladiator


9.98


-0.77


Einstein


9.97


-0.72


Brompton


9.86


-1.07


Alchemy


9.84


-1.03


Xi 19


9.80


-0.93


Zebedee


9.80


-1.05


Timber


9.79


-0.82


Cordiale


9.78


-0.76


Marksman


9.76


-0.63


Gatsby


9.75


-0.81


Deben


9.74


-0.91


Solstice


9.57


-0.88


Consort


9.45


-0.67


Robigus


9.43


-1.39


Nijinsky


9.42


-0.91


Claire


9.30


-1.06


Mascot


9.28


-0.90


Malacca


8.96


-0.79


Hereward


8.74


-0.74


Soissons


8.46


-0.80


Varieties performing well as second wheats in both absolute and relative terms are highlighted in bold.


Varieties performing notably poorly in either case (yield less than 9.5 t/ha or yield difference greater than 0.85 t/ha) are highlighted in red.


Source: CEL Recommended List 2008/9

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