While the importance of establishing oilseed rape in the autumn is well understood, the proper nutritional demands and requirements frequently go underestimated – with a noticeable impact on yield.

Timing

The ideal timing for establishing OSR for strong growth during winter is in August or the beginning of September. This enables the crop to properly form and lessen the risk of frost damage when temperatures drop.

Cabbage stem flea beetle is a major concern for farmers however, particularly during August. OSR crops are at their most vulnerable during emergence, and the prevalence of adult beetles can possibly result in total crop failure. A robust pest management programme is essential – to avoid flea beetles by delaying sowing would be counterproductive, as the crop will not establish properly before winter.

“What you ideally want is a nice healthy crop going into winter,” said Natalie Wood, country agronomist at Yara. “This is important so that the OSR can cope with the stresses encountered during winter such as low temperatures, potential water logging and frost damage.”

Nutrition

Nitrogen is an important nutrient to ensure strong establishment. The amount of nitrogen taken up by the plant before winter is about 60 to 100 kg, supplied by the soil, as well as fertilisers. If you’re in a Nitrate Vulnerable Zone (NVZ) then regulations only allow 30 kg of N per hectare, so it’s worth making adjustments if necessary. Weather conditions, rainfall level, soil health, and temperature are also important considerations when applying N.

To achieve excellent quality and yields, the best option is to apply an NPK product.

“Phosphate is essential for strong root growth and shoot development,” said Natalie. “This gives the crop an extra boost in the autumn when it's trying to get up and away quickly, making sure it's got everything it needs.”

Placement

Placing the fertiliser in bands helps ensure nutrients are located where they are needed, helping crops to achieve vigorous early growth. This also boosts the efficiency of uptake – by applying fertiliser in bands, farmers can apply in rates at about half of their usual autumn broadcast applications, with no reduction in N response.

Placing fertiliser along with the seed itself ensures that the nutrients are exactly where they are required for optimum uptake. When placed above, the seed will grow through the fertiliser, increasing the level of nutrient uptake. “Placement is particularly important for phosphate,” says Natalie Wood. “Phosphate is very immobile in the soil, only able to move less than one millimetre. The closer the fertiliser is to the seed, the easier the plant can access it.”

Strategically placing fertiliser also helps reduce costs due to requiring a lower amount per hectare. Instead of 30kg of N per hectare, about 20kg can be used due to the close proximity.

Natalie said: “If you’re concerned about your OSR crop being a bit patchy or underwhelming, it’s important to invest time and resources to give it a good start in the autumn. Different strategies and products can help avoid the various pitfalls that often delay OSR establishment. Strong OSR growth in the winter is possible with the right tools and approach.”