Establishment recipe maintains OSR’s key rotational role

Despite serious pressures from flea beetle, slugs and game birds as well as the wettest winter on record at Tarrant Gunville near Blandford, all but a very few of the 100 hectares of DK Exsteel planted at Eastbury Estates this season are going through to harvest. And in gratifyingly good condition, at that.

This clearly proves the value of the six-point establishment recipe developed through almost a decade of research and development on the Farquharson family’s 480 ha Dorset iFarm, ensuring the crop maintains its key role in the downland rotation.

“Winter OSR is crucial in keeping on top of black-grass here,” points out operations manager, Dave Thompson. “It allows us to make the most effective use of clethodim and propyzamide both ahead of and after the first cereals that are our Number One earners.

“In recent years we’ve stretched the rotation and included an extra break. We now follow the oilseed rape with wheat or hybrid seed barley, a second cereal (either wheat or spring barley), spring beans, then wheat or seed barley again before going back to OSR. That way we get at least two good grassweed clean-ups every six years.”

Dave Thompson in his 2024 crop of DK Exsteel

Back in 2019, with only 33ha of the 70ha planted surviving to harvest and averaging just 3.3t/ha, there were serious question marks over OSR at Eastbury. A 3.9t/ha average wherever the crop established well enough in the very challenging season coupled with a disappointing experience with winter beans, however, persuaded the family to stick with it and do everything they could to improve their establishment success.

“As part of the iFarm network we’ve learnt a huge amount about establishing winter OSR from the Agrii trials we’ve been involved with over the years,” Mr Thompson explains. “So, to keep the crop in the rotation we knew we’d have to redouble our efforts to improve the establishment on which its performance depends.

“Working closely with our agronomists, we now focus on the six areas of establishment agronomy we’ve found to be most crucial. We drill the fastest developing hybrid we can into a long cereal stubble with the least possible soil disturbance. We avoid drilling either too early or too late, place fertiliser with the seed and, wherever possible, sow a buckwheat-based companion crop around 10 days ahead of the OSR.

“We try to leave a 4-6” stubble into which we sow the companion with our old Moore Unidrill in mid-August as soon as the cereal straw is baled and removed.

“Then, towards the end of August, we drill our chosen hybrid at 50 seeds/m2 and a starter fertiliser placed in the row using our 6m Horsch Sprinter with Dutch openers, disturbing as little of the soil and emerging companion crop as possible. That and our no pre-em/no early graminicide policy means the emerging crop stays well concealed from both the beetles and game birds until it bursts through covering canopy, by which stage it is safely established.”

This recipe has proved highly effective, allowing the Eastbury Estates OSR to consistently average between 3.7t/ha and 4.2t/ha – depending on conditions – since 2020. And this with new crops emerging in close proximity to crops harvested the previous season in the ‘non-blocked’ rotation.

Direct drilling into a long stubble already sown with a companion gives OSR the head start it needs over pests at Eastbury Estates

In a season where the challenge from both CSFB and slugs has been particularly intense, this year’s crop of DK Exsteel is underlining the value of the approach. A local deer problem and 10 days of hot, dry weather in early September didn’t help. However, it powered away from late September to reach 75% crop cover and a GAI of 2.0 by mid-November and came through the very wet winter with a population of around 30 plants/m2 to develop a nicely-branched, well-podded canopy.

“We’ve found that fast autumn development rather than just vigour is one of the most important things in getting a good crop,” reports agronomist, Jazzmyn Jex who co-ordinates the large annual iFarm trials at Eastbury. “OSR’s ability to tolerate flea beetle and slug damage is all about how much leaf area it puts on ahead of winter. And fast development is equally important in helping the crop grow through its companion.

“We’ve monitored speed of development across varieties and treatments in all our trials here since 2017, using a combination of GAI, NDVI, and manual plant counts and leaf size measurements. Hybrids are always noticeably superior to conventional varieties in almost every respect, and DK Exsteel has long been the best autumn developer of all.

“It’s no coincidence that this hybrid has proved the most consistently top-performing variety in our national trials with more than 40 varieties for every one of six years in which it has been included. This and the considerable gross output advantage it has shown over previous farm favourite, Inv1035 is why the farm’s entire crop is down to the variety this season.

“We also value DK Exsteel here for its excellent all-round disease and pod shatter resistance, not to mention standing power. But its superior autumn development ability is what really sets it apart; particularly so where autumn conditions are challenging.”

DK Exsteel had a noticeably larger leaves and a higher plant count in mid-October than other varieties in the latest Dorset iFarm trials

Of course, the right start is essential to allow the variety to express this character. Which is why the estate’s companion crop-based establishment approach is so important.

Even on a farm that has never grown OSR, Ms Jex’s Agrii colleagues have recorded surprising levels of adult beetles on freshly moved soil ahead of other autumn crops, underlining the importance of minimal soil disturbance – even when establishing a companion ahead of the crop.

The team has tried out a range of companions at Eastbury over the years. This includes phacelia which proved really good at both deterring pests and encouraging bees but far too competitive in a mild winter, cutting crop yields by 1.4t/ha.

They have settled on 10kg of buckwheat as their standard, and this season have found a combination of fenugreek with buckwheat and vetch particularly valuable, the curry smell being off-putting to the game birds that have always been such a headache.

Minimum disturbance companion crop drilling into long stubble with the disc-based Unidrill reduces the initial attractiveness of the ground to adult beetles. Direct Sprinter drilling the OSR into the emerging companion – again with the least possible soil movement to attract pests – means it emerges well-disguised beneath a 2-3 week old companion and volunteer canopy.

“The companion dies back just as the OSR grows away strongly and clethodim deals with any cereal volunteers and holds back the black-grass which we hit hard with propyzamide at its best timing, together with Belkar (Arylex + picloram) for extra broad-leaf control wherever necessary,” says Miss Jex. “This is a really effective strategy for the rotation as much as the crop itself.”

Placing a specialist AgriiStart fertiliser giving 30kg/ha of nitrogen, protected phosphate and added boron with the OSR at drilling has also proved a valuable element in the establishment jigsaw; especially so in seasons where early rooting and crop growth has suffered from either too little or too much soil moisture.

DK Exsteel-s thick collar and branching right from the base are what Jazzmyn Jex is looking for in an OSR crop

The final element of the recipe is to drill neither too early nor too late. Drilling in the first half of August has resulted in big spring problems with CSFB larvae in the past, while sowing beyond the first few days of September is definitely out given the estate’s game bird and slug problems.

“The last week of August is invariably our optimum timing,” Mr Thompson confirms. “It means the OSR emerges comfortably after the initial peak of flea beetle migration. This works well alongside everything we do to discourage the adults on the one hand and get our crop up and away fast on the other.

“We think we may be able to improve our recipe still further by drilling the OSR as well as the companion crop through discs rather than tines as we do with our Sprinter. That way we would disturb less soil to attract beetles and cause less disturbance to the earlier-sown companions. But since this would require a new two-tank drill, it all depends on the finances.”

Overall then, Eastbury Estates has found a reliable way of ensuring winter oilseed rape retains its key grassweed control role in a profitable cereal-based rotation that would otherwise be hard to maintain.

The crop certainly doesn’t come without risk. Not least with an up-front cost of around £250/ha before Christmas. But the establishment approach the team has developed really helps to minimise the risk of the crop failing to turn a profit while fulfilling its important agronomic place in the rotation. All the more so with SFI payments totalling around £200/ha now on offer for the combination of direct drilling, companion cropping, no insecticide use and variable rate nitrogen already employed in the production regime.

Eastbury Estate's Six Point OSR Establishment Recipe

• Leaving a long enough cereal stubble;

• Establishing a strong buckwheat-based companion ahead of the crop;

• Minimising soil disturbance at both companion and OSR drilling;

• Employing the fastest developing hybrid variety possible;

• Placing a specialist starter fertiliser with the seed;

• Drilling the crop neither too early nor too late.