Growers preparing to drill oilseed rape after one of the earliest harvests on record are being urged to wait for meaningful rainfall before sowing, rather than working to a calendar date.
Florentina Petrescu, oilseed rape product manager for Limagrain UK Field Seeds, says hot, dry summer conditions have left soils critically short of the moisture needed for reliable establishment.
“There needs to be a decent amount of rain to restore moisture levels to where they need to be to sustain a rapidly emerging rape crop,” she says.
Oilseed rape seed must continue taking up water after initial germination to support emergence. If soil moisture runs out, seed can start to germinate but fail before the crop is out of the ground.
“How often have we seen seed that has started to germinate, only for it to wither away through lack of soil moisture before completing emergence?” says Ms Petrescu. “This shows how sufficient moisture is needed in the soil to start the process, followed by further rain after drilling.”
Her advice is to be guided by seedbed conditions, not fear of missing an early drilling window.
“Many will be worrying about compromising establishment by holding off drilling until conditions improve. However, holding off does not compromise yield,” she says.
Later-drilled rape can still perform strongly when sown into the right conditions, and hybrid varieties can bring added vigour, faster emergence and early biomass accumulation.
Ms Petrescu points to crops drilled in mid-September on the Lincolnshire Wolds that have achieved yields above 6t/ha, showing there remains high yield potential for September-sown crops where moisture and seedbed conditions are right.
“It is crucial to give the crop the right conditions to establish from the start,” she adds. “Drilling when conditions are not right means yield potential has already started to be eroded before the crop is even out of the ground.”
The importance of drilling into favourable conditions has been underlined by Rutland grower Sarah Bell, whose 17ha crop of LG Armada was drilled into a firm, moist seedbed last August after timely late-July and early-August rain.
The crop yielded strongly at 10% moisture, fully justifying the decision to grow oilseed rape as part of the farm’s rotation.
“It is a strategic decision to grow oilseed rape, based on a risk-versus-reward calculation,” says Ms Bell. “This year it has certainly paid off.”
She says Limagrain varieties are attractive because of the genetic resilience bred into them, including disease resistance, strong vigour and rooting ability.
On her mixed farm, soils benefit from the legacy of farmyard manure. The LG Armada followed spring barley on a relatively light but well-bodied site, with minimal carryover risk from cover cropping and enough moisture for early drilling.
Berseem clover was used as a companion crop, while autumn nitrogen, spring nitrogen and sulphur were applied. Fungicide and other inputs were kept to a minimum in a low disease-pressure season.
Despite rainfall from April to June being around 25% below average, with rain arriving in two heavy bursts, the crop stood seven feet tall by mid-July harvest.
“It has really shown what can be achieved when conditions allow full genetic potential to be realised,” says Ms Bell.
For the season ahead, both growers and advisers say the message is clear: wait for moisture, drill into the right seedbed, and give the crop the best chance of establishing strongly from day one.
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