4 June 1999

Growers anticipate higher yields from move to thin crops

HGCA levy-funded work

suggests a new approach to

cereal management can reap

big rewards. Louise Impey

hears what the experts have

to say and finds out how two

growers are already on their

way to reaping the benefits

MANIPULATING seed rates and nitrogen use to produce the right crop structure helps boost yield and reduce reliance on plant growth regulators and fungicides, according to HGCA-funded research.

Two growers already exploiting those findings are nervously watching as thin crops approach harvest. Will the promised yield benefits follow?

Growers prepared to adopt the new approach must have the confidence to see it through, especially in early spring when crops appear thin and unlikely to achieve optimum yields, say the experts.

ADAS senior research consultant John Spink believes there is huge scope for reducing seed rates across most UK arable farms. Seed cost savings of £14-25/ha (£5-10/acre) can be made immediately.

"But its important to then manage the crop canopy accordingly so yield potential is achieved," he says. "It means that farmers are going to have to accept thinner looking crops – were only aiming for 600 shoots/sqm at ear emergence.

"It is more risky to have a too high seed rate than it is to go very low," he adds. "Lush, thick crops are prone to disease and lodging. With this approach, growers are encouraged to grow the right crop structure by measuring the canopy."

His ADAS colleague David Parish agrees and has put the theory to the test at Bedfordia Farms, Milton Ernest, near Bedford. Arable manager Bob Green has been persuaded to drill a field of Abbot at 200seeds/sq m, which is much lower than his normal 350 seeds/sq m.

"We drilled it on Sept 23 and the seed rate struck me as being very low," says Mr Green. "As it was following oilseed rape, I was very concerned about slugs, so I used slug pellets on that particular field."

Mr Green admits that he erred on the side of caution at drilling. "We were set a target of 150 plants/sq m in the spring, each with four tillers. In fact, we recorded 700 tillers/sq m this spring."

Nitrogen use has been geared towards achieving a canopy size or leaf area index of six. A soil mineral nitrogen test done by Mr Parish revealed 140kg/ha of N already existed, so an extra 60kg/ha of nitrogen fertiliser was all that was required.

"We applied 39kg on Apr 12 and a further 30 kg in mid-May," says Mr Green. "Thats much less than we usually use here – on our conventional crops Ive applied 180kg/ha in two splits."

Wheat yields at Bedfordia Farms average 9.5t/ha (3.8t/acre) for milling varieties and 10.5t/ha (4.25t/acre) for feed. Although initially concerned about the visual differences, Mr Green is now more confident about the outcome.

"We definitely have thicker, stronger stems in this field and better root development," he says. "But I hope we havent underdone it. Ill be watching with interest when we combine the field."

His savings to date are £15/ha (£6/acre) on seed – which is farm-saved, and £23/ha (£9.30/acre) on nitrogen. In addition, he has only made one pgr application with chlormequat, instead of the usual Terpal (2-chloroethylphosphonic acid + chloride) programme.

"If it yields well, then I will be tempted to adopt the strategy more widely across the farm. But it takes nerve and confidence, especially when your neighbour looks over the fence." &#42


More efficient crop production is just one of the themes that will be dealt with in a special Plan Your Day feature at the Cereals 99 event. To help growers make the most of their time at the show key industry organisations are providing a focal point for all enquiries. So, whether crop production, farm strategy, better marketing or cost control are the key issues for you, be sure to start your day at Cereals 99 with a visit to the Plan Your Day stand.

Lower seed rates mean lower costs

Northants grower Andrew Pitts has taken a bold stance since learning about the HGCA findings and reduced seed rates by one-third across his whole farm.

"We use farm-saved seed so were saving around £14/ha immediately," he says. "Our nitrogen and pgr bill will be a lot less this year as well."

Mr Pitts admits to being concerned about slugs and has drilled deeper than normal to save on the expense of slug pellets. And he is currently seeking advice about disease control. "We know that traditional, lush crop canopies are more susceptible to disease. I need to know whether to reduce rates or use different fungicides with a thinner crop stand."

ADAS advice based on HGCA-funded trials was to go for 0.5l/ha of Landmark (epoxiconazole + kresoxim-methyl) at leaf three emerged. "It will help prolong the canopy," says Bill Clark of ADAS Boxworth. "The strobilurins have given growers an extra tool for managing the crop.

"On thinner crops, Landmark will be better than Amistar. Theyll stay greener for longer," he adds.

Mr Pitts, who farms 607ha (1500 acres) from Grange Farm, Meres Ashby, also admits to being concerned about the state of his thinner crops at certain times during the growing season.

"It has been alarming at times. But a fair amount of our wheat went flat last year, so crops were too lush at higher seed rates. Im expecting better yields from lower seed rates."