Challenging Wheat Agronomy - Agrii - Connecting Agri-science with farming

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December 12, 2012

Challenging Wheat Agronomy

Like most, Tom Goodman and Todd Jex’s wheat yields were around 20% down on expectations last season. The 12.7t/ha the two young Agrii agronomists harvested from the  Best of British Wheat challenge crop of KWS Santiago they grew on Stephen Moore’s Manor Farm, Stapleford near Salisbury, though, certainly wasn’t disappointing by any standard.  All the more so for coming from thin chalk ground in a low yielding year.

Yes, the very wet season did favour light land. And the crop only extended to three quarters of an acre as a field-scale trial.  However, it out-performed all but three of the 1230 or so small Recommended List variety plots across the UK which set the annual benchmark for wheat trial performance.

More importantly, it yielded almost 2t/ha more than an identical area of the same variety grown alongside it to a current Top 25% agronomic standard, delivering a very welcome extra gross margin of more than £85/ha.

So how exactly was this impressive result achieved and what lessons might it have for  growers keen to push commercial wheat performance forward from its present national plateau ?

“Perhaps the most important thing we did was set the bar high,” explains Tom Goodman. “Our aim was to harness the best of current agronomy to produce 15 t/ha from far from ideal wheat ground. We planned and managed the crop with as much precision as we could to do just this.

“We didn’t stint on the inputs. At the same time, though, everything we did was prescriptive. We only applied what modern agronomic science told us was needed.  We employed only the equipment and facilities available on the farm. And we were as constrained in our spray timings as everyone else by the weather.”

Compared to the Top 25% standard, the Agrii challenge crop received an additional
100 kg/ha of N to RB209 guidelines and within N Max, applied in five splits against a more normal three. The extra nitrogen was carefully balanced with a broad range of other nutrients based on a soil test in early November and successive leaf tissue analyses in March, April and May.

Significantly more sulphur and magnesium and slightly more potash were applied to the challenge crop to satisfy the desired yield potential and to correct particular imbalances revealed by the tissue testing. In addition to extra Nutriphite PGA, it also received markedly more copper, boron and zinc than the standard  regime.

To balance the extra N too, three PGR applications were employed – at T0, T1 and T2 – against a single T1 spray.  Like the standard regime alongside it, the challenge crop had a T4 as well as T3 fungicide to combat Septoria. It did, however, benefit from an SDHI component at both T1 and T2 compared to just T2, together with higher triazole rates at all timings and an autumn mildewicide.

“With exactly the same sowing rates on September 27, seed treatments, herbicide and insecticide inputs, variable costs were £300/ha higher for our challenge crop,” Todd Jex reports. “The extra 1.9 t/ha we harvested at a virtually identical bushel weight meant a £86/ha gross margin advantage at a feed wheat price of £200/t.  And this without taking any account of its 12.8% protein analysis compared to 10.7% from the standard regime.”

Detailed Agrii record-keeping shows the extra yield came primarily from a combination of 14% more ears/m2 and nearly 50% more grains/ear. The agronomists attribute this to two key factors – better nutrition and canopy management, and better disease control.

“Our fertilisation and PGR regime produced a visibly different crop architecture,” points out Todd. “Despite having a lot more N, the challenge crop was noticeably shorter than the standard with no hint of lodging. It also had markedly longer ears as well as more of them.

“Critically too, we recorded major differences in green leaf retention. While 80% of Leaf 3 and 15% of Leaf 2 were lost to disease by the end of June in the standard regime, our challenge crop lost just 8% and 0% respectively.

“The lack of sunshine prevented us hitting our 15 t/ha target. But the performance we achieved really underlines the value of setting-up wheat yield with the best possible nutrition and canopy management then maintaining the greatest photosynthetic capacity through to maturity whatever the weather,” he stresses.

“Our challenge recipe certainly isn’t for everyone,” accepts Tom Goodman. “Even in one of the worst wheat years in recent memory, though, it shows what can be achieved under farm conditions with the best possible agronomic attention.  There’s no single magic ingredient. Just like the British cycling team, it’s all about doing everything that little bit better.”

With this experience, Tom and Todd are currently extending their challenge work to one hectare plots of a different variety on a different farm. At the same time, parallel trials at Agrii’s Malborough R&D site are focused on pinpointing the most critical components of success in pursuit of the consistent 15t/ha performance that is their long-term aim. And they and their colleagues are working with growers across the country to develop the Best of British Wheat challenge across fields rather than merely field-scale plots.

At a Glance – 2012 Agrii Best of British Wheat Challenge

KWS Santiago

Top 25% agronomy crop

Agrii challenge crop


Crop height

83    m

68 cm

-15 cm

Ear number








Leaf 2 disease loss




Leaf 3 disease loss





10.8 t/ha

12.7 t/ha

+1.9 t/ha





Variable costs




Gross margin *




*Assuming £200/t feed wheat price regardless of quality


At Manor Farm, Stephen Moore found the Agrii challenge work very revealing. Especially so as he and his father Roger have been knocking on the door of 15t in the past with fields going into wheat after pigs.

“Nutrition is the key on our hungry, high pH soils,” he explains. “So it was interesting to see the value of repeated tissue analyses in fine-tuning nutrient applications. It was also just the year to see the benefit of a really robust fungicide programme.”

Although always wary of absolute yields in plot trials – even with strips of nearly an acre – Stephen found the yield difference between the 15t/ha strip and the standard grown to a regime similar to their own alongside it particularly instructive.

“The challenge crop always looked much better than the standard,” he recalls. “It stayed far greener and, despite the extra N, was noticeably shorter.  It was the last crop we combined and I have to say it was a bright spot in one of the worst harvests we’ve had in recent years. I’m sure it would have done 15t in almost any other year.

“Seeing what’s possible even under these conditions gives us something to aim at and useful insights into things we could do to consistently improve wheat margins across our 1300 acres.

“One swallow certainly doesn’t make a summer, though,” insists Stephen. “So we’re keen to work with Agrii to extend the study this season – across half a field, if we can. We need to establish how achievable and consistent this sort of agronomy can be commercially.

“It’s a lot of extra input spend and this sort of output increase would have implications for our grain storage, amongst other things. But you certainly can’t argue with the extra value Tom and Todd’s recipe has delivered so far.”