Consider boron in your rape crop this autumn

Challenging conditions for oilseed rape are making it increasingly important to maintain the momentum of established crops this autumn.

Crop nutrition expert say growers should pay special attention to foliar nutrition – and in particular boron – to ensure oilseed rape is sufficiently robust ahead of winter months and has the best chance of withstanding cabbage stem flea beetle.

“Larger rape plants are much more likely to withstand the adult grazing and larval phase of flea beetle attack and will be more robust when it comes to freezing temperatures,” says Chris Bond, product manager for crop nutrition and plant health at FMC.

Nutrient deficiency

FMC carries out annual tissue testing to monitor trends in crop nutrients. In recent years, it has identified declining levels of boron in rape. In 2021, 26% of tested crops were deficient. This year it jumped to 42%.

“Over the past three years we’ve seen boron deficiency creeping up,” says Mr Bond. The micronutrient is particularly important after the four-leaf stage because it influences crop growth and frost resilience over winter by strengthening cell walls.”

Boron also has a part to play in flowering, explains Mr Bond. “Although flowering is quite a way off, the rape starts to develop florets at the base of the plant as early as the autumn – so making sure the plant has enough boron to influence this is important as it ultimately could impact yield.”

‘Good choice’

Mr Bond recommends an autumn application of boron mixed with other micronutrients to optimise Nitrogen Use Efficiency (NUE) and give the crop a boost.

“Bo-La is a mixture of boron and molybdenum, which can address boron deficiencies but also help boost NUE as in order to take up nitrogen, molybdenum is needed,” he says.

“If you’re looking for a ‘multi-vitamin’ for your crop, Stoker is a good choice. It contains boron and molybdenum but also manganese and magnesium, which support photosynthesis, and sulphur which is another important element.

Rape crops come under heavy fire in the autumn and winter months – but a small investment in foliar nutrition can give crops a boost and help them emerge from the winter in a competitive state, adds Mr Bond.

“These products can be applied with other crop protection products, such as autumn fungicides or grass weed programs,” he explains.