Many oilseed rape growers achieved record yields in 2011. Why, and what lessons can be learned to help build on that success?

Last season the UK average oilseed rape yield hit a new high of 3.9t/ha. That performance marked an acceleration in the yield increase seen over the past two years and a step-change on the decade before that, when yields averaged just over 3.1t/ha, according to DEFRA figures.

Despite this, crop performance still appears well adrift of the 5t/ha average that many experts agree is achievable. However, 5-6t/ha crops were common enough in 2011 and closer examination of the factors driving that performance shows the gap could be bridged, says Pete Berry, senior research scientist at ADAS.

“The weather was probably responsible for at least half of the yield uplift,” he says. “The open autumn helped establishment, so we had very even crops going into winter. Fortunately, snow cover protected most crops during the long hard winter.

For more on this: See all of the articles on High 5 OSR yields

“The dry spring then restricted growth and N uptake, so we had more open canopies at flowering than usual.” This and the sunny April meant there was plenty of light to encourage optimum seed setting. Rain returned in time for most crops, and the cool June and July prolonged seed filling.

Technical expertise was responsible for a decent chunk of the yield increase in many situations, says Dr Berry. “Achieving a low to moderate plant count of 30-40/sq m going into winter is very important. And avoiding too large a canopy is critical. Many growers now assess green area index to achieve the optimum structure, by manipulating the timing and amount of nitrogen and using growth regulators. These can also reduce lodging, another important factor behind last year’s high yields.”

Phoma

Disease pressure was also low, partly due to weather, but also due to effective use of fungicides in autumn against phoma.

There is still plenty of room for improvement, both through advances in breeding and better management, says Dr Berry. “The UK environment is perfect for high yields – the current potential if the best traits seen in current varieties could be combined with the best management is around 6.5t/ha, never mind 5t/ha.”

There are two ways to increase yield: increase the number of seeds, and increase seed weight. A 3.2t/ha crop will typically have 80,000 seeds/sq m, each weighing an average of 4mg. A 6.5t/ha crop could be achieved with 130,000 seeds/sq m, each weighing an average of 5.5mg.

Bringing flowering forward a week and reducing flower cover by about a third through low plant populations, correct N management and growth regulator use would achieve the necessary increase in seed number, Dr Berry explains.

Similarly, seed weight could be raised sufficiently by extending the seed filling period by six days through better rooting (cultivations and PGRs), more foliar N and complete disease control, as well as increased light use efficiency (improved canopy management and reduced lodging).

“There’s no doubt that better technical expertise is starting to pay off. We do see some farmers regularly achieving 4.5-5t/ha and, soil type permitting, there’s no reason why this should not be seen much more frequently.”

Driving yields

ProCam’s 4Cast data, which accesses crop performance across 400,000ha of arable land from Scotland to the south coast, illustrates the wide range of yields that occurs within seasons and therefore the potential to increase those yields, says ProCam’s national agronomy manager Nick Myers.

“Over the past decade average yields ranged from 3 to 3.7t/ha, but the top 25% achieved 4-4.5t/ha. Last year the average was just over 4t/ha, but the top 25% averaged 5.2t/ha, and quite a number got close to or topped 6t/ha. That suggests 5t/ha is certainly within reach of most UK growers.”

Better agronomy is undoubtedly driving yields, he believes.

“As well as benefiting from good establishment and canopy management higher yielding crops tend to have a more managed and higher level of pesticides – for example, many crops had five well-timed fungicide applications last year,” Mr Myers notes.

“They also received better nutrition in the form of later N and micronutrients; last year a lot of foliar analysis was carried out and some quite obvious trace element deficiencies were identified, showing that attention to detail does pay.”

Variable costs now average £450/ha, according to 4Cast data. The best growers spent just £16/ha more to achieve their 5t/ha plus yields, but achieved paybacks approaching £400/t, says Mr Myers.

“Almost all of the value of the extra yield goes straight on to the bottom line – it costs very little more to achieve it. The key is better management, and that will become increasingly important as costs of production continue to rise.”

Good establishment

Many of Agrii’s customers achieved an average of 5t/ha last year, says technical development manager Philip Marr. Although weather played a big part, it shows the principles of good establishment, correct plant populations and canopy management work, he adds.

“Yields over the past three to four years have been climbing, and averaged 4-4.5t/ha,” he says. “I believe with better varieties coming through plus the adoption of better management, we are seeing at a real step-up in performance.

“We could see similar yields to last year in 2012. We’ve seen a swing towards higher yielding hybrids over the past couple of years which develop faster and have very good resistance to both light leaf spot and phoma.

“There is plenty of yield potential coming through – Monsanto has predicted new varieties will increase yields by 3% a year for the next 20 years.”

That, coupled with improved crop management, will push the UK’s overall average to 4.25t/ha by 2015, he predicts, and to 5t/ha within the next decade.

Many observers – Mr Marr included – believe there is plenty of potential to pull that timescale forward through widespread adoption of better agronomy techniques. This will be spurred on by better rapeseed prices and increased confidence to invest. “Until a couple of years ago people were just listening to advice – more and more are now listening and doing.”

Over the next 12 months, the High 5 series will help growers push yields higher by focusing on key agronomy pointers during each of the four main periods during a crop’s life.

At the end of June, the spotlight will be on preparation to establishment to help growers give their crops the best possible start.

The 2012-2013 High 5 Challenge

Over the next 12 months, the High 5 series will help growers maximise yields by focusing on key agronomy pointers during each of the four main periods during a crop’s life. These will include:

• Preparation to establishment (August to October), covering which is the best variety at the right seed rate for your conditions
• Establishment to emergence (November to February), covering how to maintain the right population of plants for floret initiation
• Emergence to canopy (March to April), covering how to achieve the right canopy for optimum light interception and yield building
• Canopy to harvest (May to July), covering how to capture as much yield and oil content as the conditions allow.

At the end of June, the spotlight will be on preparation to establishment to help growers give their crops the best possible start.

Why the high 5 challenge?

Farmers Weekly is teaming up with Dekalb and BASF to help growers increase average rapeseed yields to 5t/ha. National yields climbed to their highest-ever average of 3.9t/ha last season and we saw from many growers that 5t/ha is eminently achievable. Building on the initiative with Dekalb in 2011, in 2012-13 High 5 will provide advice around the four key parts of the growing season to help growers maximise yields.

Sponsors’ message

As UK oilseed rape breeding and crop protection leaders, our overriding aim is to help growers maximise the contribution OSR makes to their farming businesses through first-class genetics and chemistry with the best high output management advice.

Dekalb varieties are bred to deliver the most reliable output, efficiency and manageability even under the most challenging conditions.

The BASF oilseed rape portfolio provides a wide range of innovative crop protection solutions developed through a long-term commitment to R&D.

Together in this initiative we wish to share the latest guidance from leading crop specialists and the practical experience of growers maximising their OSR performance.