24 August 2001

CANOPYCONTROLISCHALLENGE

The DTI, HGCA and ADAS-

funded Sector Challenge

project aims to get growers

using the latest crop

management techniques for

wheat. Edward Long reviews

the lessons learnt by two

growers involved this year

and relays the comments of

the ADAS advisors involved

THE importance of a good seed-bed is top of the list of lessons John Hollingworth, of South Farm, Letwell, has learned from taking part in the Sector Challenge project.

He now hopes to apply crop management skills acquired on first wheat to boost second wheat performance on his 777ha (1920 acre) farm on the Yorks/Notts border.

"The seed-bed is the launch pad for a successful crop and it must be prepared not manufactured," he says. "It is vital to ensure there is adequate moisture for rapid germination. About 80% of the preparation needs to be done as soon as the combine leaves the field."

A firm seed-bed prepared then will take water and dry naturally. "Volunteers should be removed with glyphosate not cultivations to avoid reworking the land."

This harvest he has 330ha (815 acres) of Claire and Consort falling to the combine.

With a thousand grain weight of 52g and a target 120 seeds/sq m for the canopy managed crops in the project, seed rate was set at 78kg/ha (0.6cwt/acre) for the early September sowing last year.

"Elsewhere I went down to 50kg/ha on the best loam and up to 100kg/ha on the stickiest clays. The crop emerged within a week, so it is clear we could have reduced it to 50-60kg/ha."

However, the open canopy provides little competition for grass weeds. Ipu application was unavoidably delayed due to the weather and there are more than usual in the crop this summer.

"Getting the timing right will be a priority this autumn," he says.

Soil mineral nitrogen tests revealed 79kg/ha of nitrogen available in February. "I was amazed there was so much. I assumed that after the wet autumn and winter there would be little left."

To achieve the target green area index (GAI) of 6, the spring application was cut from 180kg/ha to 140kg/ha (144 units/acre to 112 units/acre).

"There was no need for early N, but I didnt want to apply it all in one dollop so put half on in mid-April, the rest two weeks later. The amount saved was given back to the crop after flag leaf emergence to keep it green for longer, which seems to have worked."

The low plant population meant plants were robust and needed only a single dose of chlormequat to keep them on their feet. Disease risk is also reduced, but Mantra (epixiconazole + fenpropimorph + kresoxim-methyl) rather than a single triazole/strobilurin mix was used because mildew is a threat every season on Mr Hollingworths farm.

However, only two applications were made, at standard T1 and T2 timings and no ear wash applied.

As the Arable Supplement went to Press, crops were still to be harvested but ear counts in July showed the 500-550/sq m target had been met. Mr Hollingworth has only one regret about the project – the term canopy management.

"It has taught me a lot about growing wheat, but I wish it had a more catchy name. It sounds technically complicated and could put off some growers," he says.

ADAS angle

Andy Wells of ADAS Gleadthorpe says two main lessons have come from John Hollingworths canopy managed crop – the importance of establishment and of targeting N to actual need. "Moisture is needed at drilling and if there is insufficient drilling must wait," he says. Target plant population increases with every week that passes in September and when there is moisture the appropriate seed rate for that week must be used. "Mineral nitrogen reserves must always be assessed as no-one knows how much is available to the crop. Unless reserves are low no early N is needed if the appropriate seed rate was used – the aim is to produce grain not straw. Growers going for a canopy management system must be aware crops will look less vibrant than neighbouring ones early in the season."