Later wheat planting may explain East's increased yield variability, says Strutt and Parker
PUBLISHED: 10:00 24 November 2017 | UPDATED: 11:45 24 November 2017
A shift to later planting of winter wheat in order to tackle blackgrass weed problems may have contributed to increased variability in yields from year to year, according to analysis by rural property agents.
Strutt and Parker says while East Anglia’s average winter wheat yields have slowly climbed since the firm’s annual harvest survey began 19 years ago, growers are seeing greater variability over the past decade than they did in the previous five years.
The 2017 average of 9.1 tonnes per hectare was up 2pc on the previous year’s figure of 8.9t/ha, while in previous years the yield ranged from 10.2t/ha in 2015 to below 8t/ha in 2012.
George Badger, farming consultant and agronomist at Strutt and Parker, said: “Up until 2008 you can see that yields were relatively consistent year on year, but afterwards the variability seems to be a lot higher.
“Whilst the low of 2012 and the highs of 2014 and 2015 are a lot to do with the fortunes of rainfall and sunshine, we think there is another factor at play.
“Our survey data, which this year covers 58,000ha, is largely gathered from farms in the East of England and the Midlands where blackgrass is an issue. It is our belief that part of the explanation is a shift to later drilling, as part of a strategy to tackle blackgrass once resistance to contact post-emergence herbicides became more evident from 2010 onwards.
“Late drilling is an essential grass weed management tool, but it does result in smaller root structures which leave crops more vulnerable to weather extremes than they were when people could reliably drill in September.”
Mr Badger stressed that delayed drilling (after October 15) remained the right course of action on the worst-affected fields, as it gave growers the best chance of both cultural and chemical weed control.
But he said the data showed how important it was for farmers to make their decision on a field-by-field, rather than whole-farm, basis so that drilling takes place earlier in those fields suited to it.
An earlier-drilled crop, treated with a well-timed pre-emergence chemical application when there is moisture available, could be better than a later-drilled crop with a pre-emergence application which remains dry in poorer seedbed conditions.
“In 2017, people who late-drilled second wheats were caught by the dry conditions and lost secondary tillers to the spring drought,” he said. “This meant that crops of 6t/ha to 7t/ha were quite common in the survey.”