24 August 2001

SPEEDY DRILLERS MUST BEWARE

Early drilling is the order of

the day across huge swathes

of the UK this autumn. But

getting it right requires a

whole new approach to crop

husbandry, as Charles Abel

found when he visited a

leading farm management

company in Lincs

EARLIER this week, one Lincs estate hoped to start its winter wheat drilling campaign, aiming to boost yields and simply get the job done in good time.

But whether a single seed has been drilled yet depends on a host of factors, stresses Philip Ashton, farm manager at Malborough Farm near Lincoln for farm management and consultancy company Aubourn.

Seed rates as low as 60seeds/sq m drilled in the last week of August can deliver up to 1t/ha (0.4t/acre) more than mid-Sept drillings, he maintains.

But seedbeds must be near perfect, on the right soils, slugs must be fully controlled and autumn and spring crop management must be adjusted too.

With 728ha (1800 acres) of first wheats to drill by Sept 15 at the latest, Mr Ashton is more committed to early drilling than most. He also has a wealth of experience – good and bad – after testing the approach for several years.

"There will be a huge temptation to get on with early drilling this season," he admits. "And when the pressure is on is when mistakes get made. Growers have got to be firm with themselves and resist the temptation to go before conditions are right."

After last years drilling debacle simply getting crops established will be a key reason for early drilling, he admits. "Last year the wheat area was 25% down; this year it will be up 25%. That is a lot of extra wheat to get drilled."

But unless big changes are made to crop management, early drilling benefits could soon be lost as crops succumb to extra pressure from slugs, BYDV, weeds, autumn and spring disease and lodging.

Of those threats slugs are an obvious risk, but lodging is equally worrying, stresses Mr Ashton. "It is one of the biggest lessons we have learnt – you have got to be on top of lodging. If the crop goes over you lose yield straight away, you have more disease and you delay harvest."

Main reason for early drilling at Malborough Farm is to boost crop output. "We want to exploit the agronomic benefits of establishing crops in that small window when conditions are excellent or as near to perfect as possible. As the saying goes, one day in August is worth two in September, three in October or four in November."

The result is an average yield advantage of 0.5t/ha over mid-Sept/Oct sowings and up to 1t/ha for very early sowings.

But not all land suits such an early start. Light land is essential – anything else becomes a precarious balancing act. "You can do it on heavier sites, but the risks increase and you can not expect the agronomic benefits, only the logistical ones" says Mr Ashton.

Timing critical

"It will be tempting to get started early this year, but you have got to be firm with yourself," agrees Aubourn soils specialist Neil Fuller. "We had a perfect example with beet this year. One part of a field was drilled a week too early. It capped and struggled. The rest was drilled a week later, when conditions improved, and soon overtook it."

If drilling conditions become more marginal make a note, he adds. "It is a big help to know the crop history when it comes to planning spring inputs."

To ensure seedbeds are ready on time Mr Ashton runs separate harvest and cultivation gangs. Rape land is disced and pressed straight after harvest and again before drilling, with sub-soiling as needed. Chitted weeds and volunteers are removed with glyphosate. Set-aside and vining pea land is prepared much earlier.

Get seed rate right

Correct seed rate is then vital. "One of our biggest mistakes in the past was getting this wrong. There is such a lot of leverage from the big heads on early drilled crops that you really do need strong stems, and that means getting the seed rate right."

A detailed trial established with the Stanhay Dart precision drill last autumn shows just how little seed is required in the right conditions.

"Ten seeds/sq m was way too thin, even in the near-perfect seedbed on light land. But 20 seeds looks acceptable, and 30 may have been the optimum for the site."

Adding a safety margin means 60 seeds/sq m may be the commercial target in ideal conditions, he says. That is roughly half the 100 seeds/sq m he used last year, which is equivalent to 55kg/ha (0.4cwt/acre), itself less than half the 120kg/ha (1cwt/acre) typically used for early sowing on UK farms.

"This year we will be aiming for 60 seeds/sq m in August, rising to 100 in late August, 120 in the first week of September and 270 in the second week of September." Based on typical thousand grain weights those figures represent 30, 55, 66 and 150kg/ha respectively.

Top-notch seed

Such low drilling rates mean seed must be top quality. Aubourn uses certified seed it grows for Cargill, treated with magnesium and manganese ear sprays to boost quality and dressed to a tight size specification. Uniform seed size, for uniform emergence, is considered more important than the boldest sample.

Variety choice is all Claire, for simplicity, with early drillings getting Secur (tefluthrin) seed treatment to replace up to three foliar BYDV sprays. No slug control has been seen with the product.

Drilling depth with the Vaderstad drill is as shallow as possible, provided moisture is available. Thousand grain weight is tested meticulously to set seed rate which is then adjusted by field according to seedbed and weather forecast.

There is zero tolerance for slugs. If checks on the preceding crop or traps on cultivated land show the slightest risk pellets are incorporated or spread pre-drilling.

"We dont use extra seed, because slugs dont eat every other seed in a row. If there is a slug problem we have to sort it out or delay drilling," says Mr Ashton.

Autumn disease is a worry, but whether Baytan (fuberidazole + triadimenol) or Anchor (carboxin + thiram) treatment is better than a foliar spray is unproven. "Were evaluating it, the jury is still out." Take-all treatment is not yet considered worthwhile on early first wheat.

Weed control must then be spot on, weeds emerging rapidly and competing vigorously with the crop in the warmer conditions. Blackgrass trouble should mean no early drilling, he stresses.

Even after an early-drilled crop has established successfully the story is far from over. Spring management, including weed, disease and lodging control must be adjusted to take account of the very different characteristics of early-drilled wheat.

Fail to do that and not only could the full yield benefits of early sowing be jeopardised, but there is a very real risk that crop problems will outweigh any logistical benefit, concludes Mr Ashton.

EARLY CROPS NEED N

NUTRITION can do much to support early-drilled crops, says Aubourn soils specialist Neil Fuller.

Autumn N can help boost straw breakdown and avoid N lock-up, which could starve the crop. "A big crop going into the autumn can require a lot of nitrogen," he stresses.

Where straw has been ploughed down it can create a layer of trash requiring extra N to aid breakdown. In turn, that should avoid crop yellowing in spring as roots run into trouble.

Phosphate can also have a crucial role in the autumn, boosting rooting in particular.

"With phosphate it is availability that counts. The index may be fine, but the phosphate could be locked up by high calcium in heathland, high magnesium in a river valley or high iron on ironstone soils," explains Mr Fuller.

Applying 50kg/ha of ammonium phosphate should achieve both aims, delivering both nitrogen and phosphate.

Oilseed rapes which turn blue, purple or bronze at the two true leaf stage are a classic sign of phosphate deficiency, he adds. The seed coat provides initial nutrients, but then the soil fails to keep the growing seedling supplied.

Applying phosphate as a high phosphate fertiliser or a phosphate liquid feed like potassium phosphite can solve the problem, the latter also acting as a mildewicide. &#42