A Wiltshire farm manager has shared his top tips for growing oil seed rape.

Selecting high yielding, conventional rape varieties such as Elgar to counteract potential yield loss from cabbage stem flea beetle (CSFB), regularly walking every field and the application of digestate (in preference to conventional fertiliser) to minimise CSFB damage have all proved smart moves for business director Josh Stratton and his farm manager Tom Hallett at East Farm in Codford, Wiltshire.

The 1,640ha farming business near Warminster is now in its sixth year of using digestate and, whilst attacks from CSFB still occur on some outlying fields that the umbilical pipe system used to apply the digestate cannot reach, the remainder of their rape has remained relatively clear of damage with annual yield losses of less than 5 per cent.

Tom said: “Although we walk our rape crops every two days to check on flea beetle larvae populations and other potential disease issues we have noted a pattern in recent years where fields receiving digestate suffer less CSFB damage.

"As we use similar establishment systems and inputs as our neighbours (who have suffered significant yield losses to CSFB) I put much of our success down to our 'boots on the ground' approach and the use of digestate.”

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Alongside the farm’s main crops, which include spring and winter barley, winter wheat, spring oats and a recent return to spring peas, winter oilseed rape is still an important break crop at East Farm.

This year they harvested 270ha of rape, with the area split between four conventional varieties.

Tom said: “We generally favour conventionals over hybrids, partly on the basis of lower seed costs and partly following advice from our agronomists, Crop Management Partners. They know our business very well and we trust their recommendations.

"Whilst there’s possibly a good case to be made on greater yield potential from hybrids, high yields are only one part of the equation. We measure our success on gross margins and always evaluate our cost/ha on inputs against the final yields.”

For 2019/20 East Farm grew 110ha of Elgar, 120ha of Campus and 20ha each of Aardvark and Acacia. All were drilled from August 10-28 last year.

Tom explained: “The rape was established using a Vaderstad Top Down cultivator with a 5m Bio-drill on a one-pass approach. With all the rape varieties, particularly Elgar (which we’ve grown before) we look for good early vigour and early maturity.

"The key to rape is good establishment and early nutrition to make sure you develop large plants that stand well and are robust enough to overcome pests, disease and unpredictable weather.

"A good set of disease scores is also vital to ensure you keep input costs down. A variety such as Elgar, which has a 7 for light leaf spot, a 6 for stem canker and an 8 for resistance to lodging, ticks all the right boxes.”

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Each crop received 200kg/ha of nitrogen, most of which is digestate produced by the farm itself.

East Farm annually produces around 75,000T of PAS110 compliant digestate fertiliser from food waste.

Sulphur was applied to the rape in late February followed by two main fungicide sprays: Proline (prothioconazole) at 0.5L/ha and Azoxystar (axozystrobin) at 0.6L/ha applied at first flowering with a follow up at late flowering. For the insecticide Tom went with one application of Mavrik (tau-fluvalinate + ethylene glycol) at 0.2L/ha.

Due to the farm’s loam chalk soil (which acts like a sponge to retain moisture) and the use of slow releasing digestate fertiliser, which gives the rape a consistent feed spread over a longer period, the crops coped well with the May-June dry spell with only the Acacia fields beginning to stress and looking patchy.

Tom concluded: “When the post harvest yields were confirmed we were pleased with the overall results.

"Our best yielding rape crop was Elgar, which averaged 4.3-4.5T/ha (0.3T/ha above our 5 year average). Although we drilled it later this time (following Spring barley) we were confident it would deliver based on its excellent early vigour. The variety seems particularly well suited to the growing conditions we experience here and appears to have very few weaknesses.

"Of the other rape crops, Campus achieved 4T/ha, Aardvark averaged 3.5T- 4T/ha and Acacia managed 3.5T/ha.”