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How to successfully manage second cereals this autumn

The rotational chaos, combined with a predicted fall in the oilseed rape area for harvest 2021, will inevitably see more land pencilled in for second or third cereal crops this autumn.

To maximise output in these situations, growers are urged to consider the golden rules of successful second or consecutive cereal production, including high seed rates, targeted use of seed treatments and early spring nutrition.

Extreme winter

According to AHDB’s Spring Planting and Variety Survey, the wet winter resulted in a 25% drop in the winter wheat area for harvest 2020 as many growers switched to spring cereals, most notably spring barley with a 52% increase.

Oilseed rape has also seen a further 25% decline, which in part was down to a dry establishment period and worsening cabbage stem flea beetle damage across large parts of England.

This disruption means there are some tricky decisions to be made this autumn as farms look to get back on track, both in terms of rotation and profitability, which will have inevitably taken a hit.

Strutt and Parker director and AICC agronomist Jock Willmott says across his area from Warwickshire to East Suffolk, there is likely to be further substantial reductions in the oilseed rape area, with the majority of farms dropping the crop altogether.

He sees most other break crops benefitting, with areas of winter beans, winter oats, winter linseed or sugar beet where grown all creeping up. However, second wheats are also likely to see a surge, especially as a “second” cereal behind the large area of spring barley.

“In combinable crop rotations, there is a generally a proportion of second wheat the farm is comfortable growing.

“But its gross margin is similar to oilseed rape (see table) and more reliable if grown right. So, with many making a loss in 2020, increasing the wheat area could help recoup some of that.”

Variety choice

The first consideration for successful second or third wheats is variety, with the nutritional status of the ground after a high-yielding cereal crop likely to be low and plants requiring good nutrient scavenging capabilities to thrive.

With an inevitable glut of wheat next year, there will be pressure on price, so Mr Willmott advises growers to consider a group 1 type suitable for second wheat situations, such as Skyfall or KWS Zyatt, to attract a premium.

However, he acknowledges that because seed may be in short supply and prices high, many will look to use home-saved or over-yeared seed that didn’t get planted for harvest 2020, so may be restricted on choice.

“As they are drilled later and into a challenging situation nutrition-wise, seed rates for second wheats need to be at the top end.

“You’d typically start at about 400 seeds/m2 and move upwards depending on the quality of the land, so using bought-in seed can be expensive, especially if it’s treated.”

Take-all risk

On seed treatments, Mr Willmott reminds growers of the increased take-all risk, which needs to be assessed on a field-by-field basis before opting to use take-all seed treatment silthiofam (Latitude).

The later crops are drilled into October, the risk of primary infection drops off, so much will depend on whether growers are delaying drilling for grassweed control. However, after being caught out last autumn, there may be a trend to drill earlier this time around.

Growers should also consider field history and soil type, with heavier clays at least risk and risk increasing pressure as soils get lighter.

“On poor quality or lighter land following a host crop, you may want to consider a seed treatment and in a third cereal you’d certainly be brave not to use Latitude,” says Mr Willmott.

“Also, if you have a block of lighter land where you don’t have any experience of growing second wheat, it might be something to consider.”

Take-all decline

This is echoed by Certis seed treatment expert Tim Eaton, who says Latitude isn’t necessary in all second wheat situations, where a robust variety is drilled later, for example, and where take-all decline kicks in with the fourth and fifth consecutive wheat.

He adds that a quirk of this season is the jump in spring barley and spring wheat areas. To get rotations back on track, these may be followed by a winter wheat.

“This should also be factored into take-all risk assessments. We have data from the UK and Northern France showing a 0.65t/ha benefit of Latitude treatment in wheat grown after spring barley and 0.45t/ha after spring wheat, but that isn’t to say all sites would show as much take-all pressure.”

When sowing consecutive wheats or wheat after winter barley, spring barley or spring wheat, Mr Willmott says management will be the same, with higher seed rates and seedbed consolidation key at establishment.

Beware bromes

Grassweeds should also be a consideration, with brome moving in from headlands perhaps the biggest concern and although it isn’t fashionable, ploughing is advised depending on species present.

“You do have to keep an eye on it going in to second cereals. Sterile and great brome should be ploughed down, whereas soft and meadow brome should be left on the surface to break dormancy before cultivation.

“Generally, blackgrass herbicide stacks will take care of any autumn germinating brome, but you can get caught out by spring germinating soft and rye bromes which may require an SU treatment in the spring.”

Later in the season, strobilurin fungicides early in disease control programmes have been shown to have some impact on secondary spread of take-all and could be a consideration when planning for the spring.

Early nitrogen

With nutrition likely to be compromised in these scenarios, early nitrogen application as soon as growth begins in the spring is also crucial in helping the crop to maintain tillers and first split nitrogen rates need to be higher than in the past.

“The increased costs of growing a second wheat is a sticking point and performance can be erratic in dry seasons, but with the right management they can yield close to first wheats,” says Mr Willmott.

More information on Latitude can be found here