Experts advise how to manage contrasting OSR crops after stop–start establishment

The expert who advises on crops in Essex and Suffolk explained that, in her area, a very dry August sandwiched between catchy periods at the end of July and the beginning of September, has led to half of the crops being drilled very early and the other half planted later than usual. Now, it presents two entirely different crops to manage.

“There is no real consensus around drilling date. It’s a personal decision for the farmer. For me, it is much easier to manage bigger plants than usual up to Christmas than a backwards crop,” Ms Kenney said.

There is a month between half of her oilseed rape, which was drilled in the first week of August, and the rest, which went in the first week of September.

“Crops that went in early look very well; they have enough moisture to get away and have kept going. Later-drilled crops will require regular rainfall to get to where we want them to be, and we will also consider foliar nutrition to reduce stress and enhance rooting,” she continued.

Consider foliar nutrition this autumn

To help later-drilled crops catch up to where they are expected to be, Tim Horton, combinable crops technical manager for Agrii, recommends growers consider foliar nutrition this autumn to help develop root systems and canopies heading into winter.

He said: “A good starting point is something like Nutriphite PGA, which is phosphite plus pyroglutamic acid (PGA). It’s the PGA that affects carbon fixation and nitrogen use efficiency. And it’s the phosphite which is affecting the availability of the phosphate by mobilising phosphate in the root zone. Combining both promotes root development.

“This creates a virtuous circle. The exudates are making more phosphate available due to the improved root structure, which in turn increases the available phosphate.

“Nutriphite PGA can be used from the two-leafed stage onwards. Applying it will boost the rooting and increase the plant’s resilience. You can apply this multiple times through the autumn and winter if needed.”

Another product Mr Horton recommends for developing OSR crops this autumn is Quark, which contains zinc acetate and a small amount of nitrogen. He says that zinc promotes oilseed rape root development, much like in cereals, where it is often applied with T0 fungicides.

“Really, it’s a programmed approach to enhance the plant’s growth through the autumn. Quark can go on earlier, from the cotyledon stage onwards. It’s ideal for reducing stress in struggling backwards crops, which may be the case with some later-drilled crops this year,” he added.

‘Oilseed rape stacks up financially this year’

With the first signs of Phoma now appearing, Ms Kenney said she will consider adding some foliar nutrition, alongside a fungicide if necessary.

When it comes to fungicide choice, she added it depends on whether some plant growth regulation may be required, with tebuconazole or prothioconazole favoured for disease control and metconazole if the canopy looks too large. However, reduced sensitivity of Phoma to tebuconazole has been known, and the Agrii expert said that control should be closely monitored.

“There can be a reluctance to spend too much on oilseed rape until the spring, when it’s known if there is a crop to take to harvest, but I think you have to be careful with this sentiment. If you keep disease at bay, even with a bit of tebuconazole, and do your best to have a healthy crop going into winter, you will be helping your crop when it comes to the spring.

“Oilseed rape stacks up financially this year, and we need to look after its potential,” Ms Kenney concluded.

Read more arable news.