Pushing yields and profitability in wheat

Keeping the crop greener for an extra two weeks and maximising light capture have helped boost yields by up to 4t/ha for brothers Lawrence and Antony Bonner.

They hit the highs of 15.04t/ha in one crop, dwarfing the 11t/ha achieved in the same field, and were still able to achieve a healthy gross margin.

See also: Wheat works wonders in the Lincolnshire Wolds

Despite inputs being ramped up for the 2.5ha crop of the variety Dickens, the duo were still able to see a higher gross margin than the 11tt/ha crop of Diego crop grown in the same field using standard farm agronomy.

Larger area

Lawrence, who heads up the arable operation on the family farm, says the potential shown has prompted him to expand the 15t/ha blueprint that was achieved in the challenge crop, across a larger area next season.

“It is incredible what you can achieve, but in order to do this you have to invest in the crop and aim high by challenging the crop,” he says.

Key reasons for increase

  • Preserved the green leaf to extend the grain fill period by an extra two weeks
  • Lower seed rate to give an open canopy with more efficient light interception
  • Nutrition programme improving ear fertility 

Situated in the southwest corner of Northamptonshire, close to the town of Brackley,Cold Harbour Farm lies on heavy clay loam soils, which typically see wheat yields of between 9.5t/ha to 10.5t/ha.

Last autumn the gauntlet was thrown down to reach a 15t/ha crop as part of the Best of British Wheat -15 tonne challenge with distributor Agrii. Working closely alongside trials agronomist Greg Taylor, Lawrence was keen to keep the profit margins equally high.

World record

Inspiration on how to achieve a high yield came from the current world record wheat crop, which stands at 15.65t/ha, grown by Mike Solari, farming near the southern tip of New Zealand’s South Island.

Lawrence says a good starting point is managing his soils and rotation over the years to minimise grassweed pressure, and with regular farmyard manure applications pushed the organic content to 6%.

“When you grow 15t/ha there is a huge demand on the soil so everything has to be right,” he says.

Opting for spring beans in the previous crop offered a perfect entry into winter wheat and allowed him to select a blackgrass-free field on the farm, reducing the threat of yield-robbing grassweed.

Farm facts

  • Farm name: Cold Harbour Farm
  • Location: Brackley, Northamptonshire
  • Cropping: Wheat, oilseed rape, winter barley, spring beans, grass leys
  • Soil type: Heavy clay loam
  • Area: 600ha

Open canopy

The fulcrum of the high-yielding wheat crop comes using a low seed rate to produce an open canopy that would allow more efficient light interception, he believes.

The crop was drilled on 6 October at a variable rate average of 250 seeds/sq m, which was compared with the farm standard of 300 seeds/ sq m and an even higher 350 seeds/sq m, using the same inputs.

“We thought the number of seeds in the ground was going to have one of the biggest impacts on yield,” explains Mr Taylor.

The aim was to achieve a similar number of ears per sq m as the 500/sq m achieved on the world-record crop in New Zealand.

Coincidentally, results at harvest showed an additional 0.8t/ha had been achieved at the lower seed rate of 250/sq m.

Light penetration

Mr Taylor explains in order to maximise the crop efficiency he needed good light penetration in to the canopy.

“What I wanted with an open canopy was three equal-sized leaves that were all seeing sunlight and helping to produce yield and contributing in equal proportion,” he adds. 

Mr Taylor points out that traditionally the flag leaf provides 50% of the photosynthesis and can shade out the lower leaves.

However, a visual assessment on 17 July showed the 15t/ha crop had substantially more green area than the standard crop, with leaf two 90% green in the challenge crop and 0% in the standard.

“As a result of all our management we had manufactured a different crop. It had almost two weeks extra life than the standard crop that was grown in the same field. 

Harvest details

  • Yield: 15.03t/ha
  • Thousand grain weight: 53g
  • Specific weight 78.1kg/hl
  • Grain protein 11.95%
  • Grains per ear: 69

Crop needs

Mr Taylor stresses that despite all the input levels being well above farm practice, everything was driven by the particular conditions of the season and the needs of the crop.

Some 320kg/ha nitrogen was applied in five splits, with 50% applied after the flag leaf. This prevented too much biomass early on, which could leave the crop open to disease and lodging.

The crop received urea and ammonium sulphate in the first two applications and liquid nitrogen for the final three.

Mr Taylor points out that the late applications allow growers to adjust their programme to meet the demands of the season, allowing them to reduce it if the potential yield isn’t there.

In parallel with applying nitrogen, plant growth regulators formed a vital part of the crop management, with two applications early on at T0 and T1.

“We applied it even when the crop didn’t look like it needed it, because we knew we were going to apply the nitrogen,” he explains.

Fungicide programme

Hand in hand with more nitrogen, the crop needed a stronger fungicide programme over the farm standard rates.

“The fungicide programme is crucial because when you are putting on more nitrogen the plant can get stressed as you are producing bigger cell structures that are more prone to disease getting in,” he says.

A strobilurin fungicide at T1 helped battle yellow rust, which was prevalent across the UK, but it also provided a rooting benefit to help the crop scavenge for nitrogen.

He opted to use a mix of, azoles, SDHIs and protectant products to battle septoria and boost yield

“It is not just about keeping the crop clean – we got the physiological benefits from the strobes and the SDHIs,” he explains.

Trace elements

In addition to this Mr Taylor targeted trace elements as key to eliminating any key yield limiting factors.

“If you are aiming for nearly 5t/ha above your normal yield of 10t/ha, you are increasing it by 50% and putting a lot more pressure on the crop. This will be highlighted in any deficiencies,” explains Mr Taylor.

A tissue analysis was carried out early on in the season and again mid-way through the season, to help address any nutrient deficiencies and aid healthy plant growth and grain fill.

He says trials have shown that crops experiencing deficiencies in trace elements such as boron, zinc and copper can see a reduction in yield.

Nutrient application

“A well-timed nutrient application bolsters and works with the fungicide application,” he explains.

“At the minute grain prices are so low, you can’t afford to lose out anywhere. This is a relatively small input but it can make a big difference, especially if you are aiming for a high yield.”

Following the success Lawrence now plans to roll out the 15t/ha blueprint across 18ha, but is cautious of aiming high every time.

“We will implement it on a larger area and across a wider range of soil types that have more weed problems, so it will be interesting to see if we can still maintain the margins.”


Challenge crop (£/ha)

Standard crop (£/ha)
















Others including herbicides and slug pellets



Total variable cost £/ha




Yield t/ha



Grain Price £/t






Gross margin




Difference in gross margin (£)


Increase in gross margin (%)




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