After a summer of severe drought across large parts of the country, and one of the earliest harvests in years, rain has finally arrived – and just when growers need it most. So with most oilseed rape now in the ground, how can growers support rapid establishment and head off the threat of pests? 

Natalie Wood, agronomist and product manager for Yaravita & Biologicals at Yara, says this year's conditions have been a tale of two extremes. "We've had very dry weather for an extended period in some parts of the country, and others further north had pretty much a normal year," she explains. Many areas also missed the overwinter rainfall needed to refill the water table, compounding the dry spell. "Thankfully some rain did come in June, just in time for a lot of the country, and it managed to save some of those harvest yields," she says. Although plenty of disappointing harvests were still reported, she notes.

Getting oilseed rape away quickly

Post-harvest, the moderate rain that fell on still-warm soils in early September created ideal seedbed conditions for drilling OSR. But committing to the crop doesn't stop at drilling. Quick establishment is the single biggest factor in how well the crop thrives.

"If you'd spoken to me a couple of weeks back, I would have advised some seedbed nitrogen or NPK to get the crop growing quickly," Natalie says. "However, if that wasn't possible, there's still time to apply a starter fertiliser to give it the best chance of survival and help it outgrow potential pest issues such as pigeons or cabbage stem flea beetle. For growers in a Nitrate Vulnerable Zone (NVZ), applications must also be planned around the relevant closed periods, with the end of October marking an important deadline for nitrogen applications to oilseed rape." 

When foliar nutrition comes into play

Timing for foliar nutrition depends on the drill date rather than the calendar. "What you're looking for really is that four to eight true leaf stage," Natalie explains – not the cotyledons, but the true leaves that follow. "It just needs enough leaf area to help the nutrients get into the crop." Crops drilled earlier might reach that stage at six leaves; later-drilled crops may be targeted nearer four.

What's important is getting nutrition into the crop before winter. OSR is a leafy, fast-growing crop through autumn, which can quickly diminish the soil's micronutrient supply. This is why Natalie recommends an application of YaraVita Brassitrel Pro in both autumn and spring. This is a formulation designed specifically for brassicas, containing magnesium, manganese, boron, calcium and molybdenum. "We want efficient photosynthesis, cell growth and structure going into winter, and support for that rapid growth phase in spring," Natalie says. 

Brassitrel Pro applications in autumn and spring can improve the yield of OSR by a third of a tonne per hectare which represents a strong return at current crop prices.

Building vital root reserves with phosphate

With drier seasons increasingly likely, building a strong root system now matters more than ever. Phosphate is the key nutrient for root development, and Natalie says foliar applications offer real advantages here. 

"Foliar phosphate is a much more efficient route into the crop," she explains. "You're applying much smaller amounts, but the crop takes up pretty much all of what you apply." For growers concerned about root development, particularly on later-drilled crops, a phosphate-based foliar product such as YaraVita Crop Boost is worth considering alongside conventional fertiliser.

That efficiency becomes especially valuable in dry conditions, since foliar nutrients are absorbed directly through the leaf rather than relying on soil moisture. "A good example this year was Crop Boost on maize," Natalie says. "I had quite a few comments back about the rapid greening effect people saw during that dry period, when the crop looked stressed and they were a bit concerned about it." Visible results like that matter to growers watching a crop under pressure – and can instil much-needed confidence in the crop. 

Cereals and the later-drilling challenge

With black grass pushing many cereal drilling dates later in the calendar, root systems have less time to establish before winter. "If you've got a small root system and we end up with some waterlogging, potentially you've got the roots retracting even more," Natalie warns, with knock-on effects into spring and any dry weather that follows. Again, building that root system with a foliar phosphate product such as YaraVita Crop Boost – applied in autumn, or held back to the T0 spring application if conditions don't allow – helps to reduce that risk.

Trial data backs up the approach. For cereals, Crop Boost also delivers a benefit of around a third-of-a-tonne per hectare, rising to over a tonne per hectare when combined with a spring YaraVita Gramitrel application. Although on average, growers can typically expect around half a tonne per hectare from that combination.

Planning for whatever the weather brings

Whether it's "the weather or pricing or everything else farmers are having to deal with," Natalie is aware that "farmers can't catch a break at the moment."

But despite recent rain and some early, gloomy predictions about El Nino, Natalie thinks the land can withstand a certain amount of rain. "It's been dry and there's still a lot of room in the water table to take some moisture," she says. "It's only when we start to see potential waterlogging that we could have issues, but these crops are pretty resilient." OSR typically shows strong spring recovery, and while cereals can also be impacted by prolonged waterlogging, they too have good capacity to bounce back with the right spring nutrition. 

For growers concerned about ground conditions, Natalie suggests drone application offers another route to get products on when travelling fields isn't practical. "We've had some applications of some of our nutrition products through a drone and this is interesting work we know growers are exploring at the moment."

"Stay responsive"

With conditions shifting, Natalie's advice is to stay responsive. "Keep an eye on the weather," she says. "If you need to tailor your approach with different nutrients, Yara has the products to match, whether that's foliar phosphate for root establishment, or the micronutrient support crops need to make it through winter and into spring."