Investment to achieve good returns from spring oilseed rape is more about spending time, rather than money advocate Oxfordshire growers Nigel and Margaret Lawrence.
Investment to achieve good returns from spring oilseed rape is more about spending time, rather than money, advocate Oxfordshire growers Nigel and Margaret Lawrence.
From the moment of emergence, the crop is under intense pressure, with timely intervention crucial to prevent losses.
Their 70 hectares of spring OSR a year, at Shirburn Farm, Watlington, is an integral part of a whole farm rotation approach to profitability, across the 300 hectares of arable cropping.
The benefits of spring OSR following autumn-sown wheat crop, in terms of control of grass weeds and as a timely and easy seedbed entry, for example, are often worth as much as the crop itself.
Achieving consistency with yields has been the Achilles heel of the crop, he says.
Combine monitoring has shown yields fluctuating from more than 3.2 t/ha, down to 0.5t/ha across the farm.
The Lawrences set an average of 1.8 t/ha as a realistic performance budget, which has typically been achieved and, providing costs can be minimised, is viable for the whole farm rotation.
As soon as the spring OSR is planted, daily inspections are started for any sign of flea beetle activity.
From the first cotyledon emergence, flea beetle can decimate seedling growth overnight, warns Mr Lawrence.
“It’s hand and knees inspection for the first signs of beetle migration, and then being prepared to act fast,” he says.
Control strategy has centred around Hallmark Zeon to target flea beetle activity and for repellence effect to limit the speed of further beetle migration.
However, control has been getting more difficult in recent years, he says.
The focus is on getting crops established as quickly as possible, but also at a low cost to minimise financial risk in case of failure.
He has mostly relied on home-saved seed of conventional varieties.
Tamarind has proven the most dependable variety on-farm, with new seed stock grown every couple of years.
Even with paying the full royalty cost on all the seed sown, it is still a relatively low initial investment.
Such is the pressure from insect damage, the Lawrences typically sow seed at rates of 6.5-7.5 kg/ha, aiming to establish 150 plants per sq.m, with seed rates tailored to seedbed and growing conditions.
With the low cost of seed, last year they trialled increasing seed rates to as much as 10 kg/ha, however results were not significantly different in established plant population and there was no advantage in yield.
All the farm’s crops are established with the minimal number of cultivation passes.
After harvest, wheat stubbles are surface tickled to encourage grass weed chit, and then sprayed off.
Further germinated weeds are killed before the spring crop establishment, moving as little soil as possible to reduce costs and retain structure.
He says spring OSR germination and initial growth can be slow, depending on soil conditions and temperatures, which makes even and precise seed placement so important.
Winter sown crop typically more reliable than spring sown. Early summer rainfall crucial for yields. Performs better on moisture retentive soils. Sow early varieties in northern regions.
Market for high-protein seed for animal and aquaculture feed. Some varieties may be later maturing. Only sow once soils are warm and dry, from mid-March. PGRO advice available.
Market for industrial crop or livestock feed. Not a true cereal break. Good options for grass weed control.
Late harvest may restrict autumn crop establishment. Join the Maize Growers Association for agronomic advice.
Huge interest for 2020 sowing. Legume crop benefit for following crop. Can perform well on lighter soils. Early maturing varieties potentially more suitable for northern regions and Scotland. Look to the PGRO for guidelines and advice.
Increasing interest from growers, with more reliable varieties for UK conditions. Limited agronomic experience. Few contracts available for this spring.
The last time the UK experienced such a difficult autumn establishment season, in 2012-2013, the subsequent area of spring oilseed rape increased by more than 750%, growing from less than 10,000 hectares to more than 91,000 hectares.
In the search for viable spring crop options this season, growers report spring OSR can work. But the crop demands very close attention to agronomy and controlling growing costs to make realistic returns.
No fertiliser is applied in the seedbed, but placement is followed up with 125 kg N/ ha, typically split in two or three applications in quick succession as the crop rapidly develops through growth stages.
As soon as seedlings are seen emerging, fields receive metazachlor as a pre- or peri- emergence herbicide, with the option to top up with clopyralid + picloram for cleavers and mayweeds where required.
All the established fields have a graminicide to reinforce black- grass control, but Mr Lawrence says he is mindful the efficacy appears to have been waning in recent seasons.
While common belief with winter OSR is that pollen beetle move onto open flowers as soon as possible and stop further damage, Mr Lawrence’s experience is that in spring OSR they will continue to feed voraciously on green buds lower down the stems, even when top flowers are fully open.
Hallmark Zeon has been his first option in previous seasons, but issues with resistance and now the loss of pymetrozine is of further concern for the crop.
“Spring OSR doesn’t have sufficient flower heads to tolerate losses to pollen beetle damage and there’s too little time for compensatory growth which can help in winter crops,” he advises.
Instead, use of anti- resistance options, including indoxacarb/acetamiprid, may need to be looked at in future.
The simple low-cost fungicide strategy orientates around Amistar as a standard application to limit Sclerotinia effects and maintain green leaf area for the short growing season crop – followed by tebuconazole.
In a high disease risk season, a second tebuconazole application may also be required.
The immense importance of break crops is not lost on Mr Lawrence.
After 15 years of simple, and profitable, continuous wheat, the legacy of black-grass left the farm almost uncroppable, with several years of rotational fallow.
Now, with the rotational approach of mixed crops and minimal pass cultivation strategy, he believes it is back on an even keel for sustainable productivity and profitability.
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