Archive Article: 1997/09/20
HOW do you grow a profitable wheat crop, using less than two full rate sprays, from seed to harvest?
Danish grower Mogens Worre-Jensen has been forced to find out. His pesticides are strictly rationed by the Government, under a green agricultural regime which aims to halve national pesticide usage.
At first, Mr Worre-Jensen was worried – as were all Danish arable producers. But despite the restrictions, he has managed to keep gross margins healthy, thanks to disease resistant varieties, and well-timed low dose sprays.
"We have learnt how to live with the pesticide limits," he explains. His solution on the 1,200ha (3,000 acres) of productive light clay loam at Vallo, Koge, just south of Copenhagen, includes British wheat variety Lynx.
This feed wheat failed to make the UK Recommended List in 1993, and so is not widely grown in Britain. Although it has excellent disease resistance, treated yields failed to match up to other UK wheats in Recommended List trials. Specific weight results were also lower than some other varieties.
But Lynxs major strength, its disease resistance, is valuable in Denmark, where sprays are limited. This is the second season that Mr Worre-Jensen has included Lynx in his wheat portfolio.
The variety has given good yields, but equally important, has routinely required only one fungicide spray, and that at a low rate. Last season it was a one-third rate Tilt Megaturbo (propiconazole with carbendazim), applied during early July. Rain in late June brought the risk of septoria.
The Lynx produced 9.6t/ha (3.9t/acre) following a vining pea crop. Variable costs were just £105/ha (£42/acre) – less than half the UK average figure for wheat.
This season the variety also needed just one fungicide spray – straight Tilt (propiconazole) at 0.2 litre/ha, at the end of June to protect the ears from septoria. An aphid spray was also necessary in mid July.
But the other more susceptible wheat varieties on the farm – Ritmo, Hussar and a small area of Reaper – have been sprayed three times with fungicides (all at low doses, 0.2 litres/ha). "This season has been relatively disease-free," says Mr Worre-Jensen. "Mildew and yellow rust have been low."
Growth regulator is included in the pesticide ration, and so Mr Worre-Jensen is keen to grow those varieties which can stand unaided. Lynx has good standing ability, but theres no doubt that the restriction on fertiliser reduces lodging risk.
Nitrogen limits are imposed on crops depending on soil type. The preceding crop is also taken into account. On Mr Worre-Jensens farm, Lynx following peas is allowed 135kg/ha (107 units N/acre), and 163kg/ha (130 units N/acre) following oilseed rape.
On the back of good yields and low input requirements, Lynx is the number two wheat in Denmark with about 17% market share. Ritmo is the market leader.
Lars Andersen of seed company DLF Trifolium markets Lynx in Denmark. "We need varieties which can stand up to a cold winter," he comments. "This season has been a real test, with cold temperatures and fierce winds from Finland and Russia. Lynx has held up well."
Danish wheats are drilled early – at the beginning of September -so that plants are well established before the winter cold bites.
Because most of the home-grown wheat in Denmark ends up as pig food, specific weight is not important. Grain prices are low (about £81-85/t ex-farm) for this harvest. Converted to the pound equivalent, this price appears higher than it really is, due to the effect of the strong pound on the sterling/krone exchange rate.
In reality, grain markets in Denmark have been low for some years – although Mr Worre-Jensen says they are better than he had been expecting. Unlike British growers last season, Danish producers did not benefit from exchange rate movements.
This harvest the first indications are that Lynx has not yielded as well as in previous years, and the varietys British breeder – John Blackman of CPB Twyford – suspects that nitrogen starvation is responsible.
Clues to the problem were visible this summer; some fields showed leaf yellowing and tipping. Danish growers tend to apply nitrogen early – just as they did when higher rates were allowed.
With limited nitrogen now available, late timings are more effective, suggests Mr Blackman. This is particularly true for late developing semi-dwarf varieties such as Lynx.
The Danish experience shows how varietal resistance becomes much more significant, if the rules change. Up to now, it has paid to go for yield in Britain, using high inputs. And so growers have failed to exploit the in-built disease resistance available in some UK varieties. But Danish growers want disease resistance – and British plant breeding can supply it. More British-bred wheats are on trial in Denmark.
British agricultural products are flying the flag overseas. In the first of a series focussing on our industrys success elsewhere, Gilly Johnson visits Denmark. Heres why a British-bred wheat is stealing a march.