“For some reason this hasn’t got through to the industry,” Professor Roger Sylvester-Bradley of ADAS told visitors to the United Kingdom’s Cereals event last month.
“It’s my last ditch hope the arable industry will start to twig that this is what it’s doing.”
Sylvester-Bradley’s name will be familiar to many New Zealand cropping farmers as the founder of the canopy management concept, whereby plant population and tillering of cereal crops is managed to maximise the interception of sunlight.
But for all the talk about canopy management over the years, in general UK farmers do not think about what they’re doing as harvesting sunlight, he said.
“Somehow I’ve failed to get that across.”
Sylvester-Bradley is working with a group of growers – 85 have signed up so far – aiming to close the gap between actual yields and potential yield, as measured by light received in the paddock. The group’s known as the Yield Enhancement Network (YEN) and costs £250 to join. (see www.yen.adas.co.uk)
For that members get automatic entry into a yield competition and analysis of how their crops performed compared with the potential of their paddocks.
Last year’s winner was Tim Lamyman, Lincs, who grew 14.5 tonnes/ha of winter wheat, a new UK record and 76% of the field’s potential in the 2014 summer.
So how does that compare to New Zealander and World Record holder Mike Solari’s 15.7t/ha grown near Gore in 2009-10?
Solar panel: this is what your crops are, Prof Roger Sylvester-Bradley told growers at the UK Cereals event.
Sylvester-Bradley said based on local weather records Solari’s crop received 50 terrajoules/ha which meant the yield was about 61% of the potential.
“So we [the British] win the percentage efficiency competition,” he quipped.
He said a typical summer in the east of England delivers just 36 terrajoules/ha and is considerably hotter than Gore or other cool cropping areas in NZ too.
“The temperature [for the world record] was three degrees cooler than our average summer temperature so everything lasts longer.”
Sylvester-Bradley noted that when most wheats had “died on their feet” by mid-July in Eastern England last year Lamyman’s crop of Kielder still had four green leaves.
He said besides getting disease control and plant nutrition right to keep leaves green, a key factor in harvesting as much light as possible is canopy architecture. Cultivars with erect leaves at an acute angle to the stem and sky are inherently more efficient than those with floppy leaves because leaves facing the sky become “saturated” with light even at low light intensities.
In contrast, erect leaves intercept less of the light allowing more to pass down through the canopy to lower leaves.
Typically there’s about six times more photosynthetic light in daylight than any one leaf can absorb so the angled leaf still gets enough light to reach maximum photosynthesis, without shading the lower leaves which in due course intercept more of the light and turn it into biomass.
