Get the most from your OSR this spring

With most OSR crops now well on their way, growers are doing all they can to ensure robust growth and higher yields. Yara agronomy operations manager, Natalie Wood, and Yara area manager, Oscar Thacker, discuss the current status of OSR crops and what steps growers can take to drive growth forwards.

“My observations over the last week or so are that OSR crops are ranging from those that fared well over winter to some that have suffered from things like pest damage,” says Oscar. “There’s a wide range. Clearly how to get those backwards crops moving is a key question for all growers and farmers out there.”

Progressing OSR growth

How can growers manage these variations effectively? “We’re aiming for a green area index (GAI) of 3.5 at the beginning of flowering,” says Natalie. “The key determining factor for that is N. Each unit of GAI needs 50kg of N per hectare to achieve that 3.5 we’re looking for. Ordinarily, OSR needs 220kg of N per hectare in spring to achieve this, in two or three applications.”

While N clearly plays the most critical role in crop nutrition, any backward OSR crops could well be suffering from other deficiencies. “If a crop has taken damage, we need to encourage those shoots and roots to regrow,” says Natalie. “We’re at a time where P isn’t quite available in the soil, but OSR crops need it. If there’s a deficit, that will only exacerbate issues for any struggling crops. Making P (and K) available during the rapid growth phase means we don’t hinder crop progress and help foster as much biomass as possible.”

Oscar concurs with this: “For forward looking crops, a nitrogen and sulphur fertiliser is the right approach. Otherwise, consider what system you’re running, and which product is right for you.”


At this time of year, micronutrients are vital for ensuring each crop can reach its full potential. Despite this, many tissue samples continue to display high levels of deficiency, indicating that the problem is more widespread than we might think.

“For OSR, the key micronutrients are magnesium, manganese, boron, calcium, and molybdenum,” says Natalie. “Using a product specific to the crop will help increase micronutrient levels to where they should be. We’ve done six years of trials and seen an average yield increase of 0.27t/ha when applying three litres of Yara’s own OSR-specific product in autumn and spring, for example.”

“We need to think beyond nitrogen and aim for efficiency with all nutrients. Choose products and tools that will help deliver the right nutrients at the right time to ensure robust and resilient growth when the crop needs it most.”

Oscar adds: “OSR prices are fairly buoyant, so it’s worth the investment. Even a crop that doesn’t look like much at first can produce a lot at harvest if given what it needs.”

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