Oilseed rape failed again?

David

Borage

Bruce Hill (Agronomist)

Borage gives an excellent entry for wheat. The late drilling date and short growing season allow good control of black-grass and provides ideal conditions to direct drill the following crop

Andrew Fairs is a farmer and borage grower himself, and says that in seven out of the last 10 years, the borage actually outperformed the wheat in terms of gross margins. However, he says, the challenge is convincing growers.

Welcoming attendees to the open day, Andrew Fairs commented that growing on contract only works if it works for both parties – so they feel it’s important for them to listen to their growers as much as it is for growers to know and follow best practice for growing borage.

Crop Development Services Ltd novel crop specialist Neal Boughton gave an in-depth borage agronomy update at the conference. He explained that Peter Fairs has been keeping weather records in the Great Tey area for the last 45 years or so, and that the average rainfall over the last 10 years versus the 45-year average suggests we are getting drier springs and wetter winters.

With seedbed preparation therefore, moisture conservation around the drilling area is key for good germination. Seedbed preparation should preferably happen in the autumn, with the aim of removing soil compaction.

Mr Boughton explained that drilling time has quite an in uence on the oil quality. A golden rules is "the lower the temperatures in the week before swathing, the higher the GLA levels in the seeds." There’s a tipping point at around 27ºC that causes the plant to ‘shut down’ the chemical processes to produce oil, as a form of heat stress. Hence, Peter and Andrew are encouraging borage growers to drill a little later in the spring.

Mr Boughton says there is actually some evidence to show that later drillings automatically have higher GLA values, regardless of the temperature, but explained that more data is needed. He is therefore urging growers to supply drilling, emergence, swathing and harvest dates in order to have these data comparisons.

The enzyme responsible for making that oil in the process needs zinc as a co-factor to function as e ciently as possible. So, could you add foliar zinc to assist borage and reduce stress during heatwaves? Mr Boughton is asking for volunteers to help with split eld trials to investigate this further.

Foliar applications of trace nutrients are advisable at rosette stage. You only need enough N to make biomass for a good tight swath – if you add too much, you increase mildew and lodging risk. Sulphur is more important as it helps the plant to utilise N more e ciently and allows the crop to produce higher oil levels.

If you have a eld which is even slightly de cient in boron, it’s important to consider adding that in order to maximise pollen production. Pollination is vital, and while other pollinators and wind can do a job to a certain extent, honey bees are essential – and the more hives, the better.

Placement of hives is important, including in the middle of larger elds if possible.

Only the brand names on the Permitted Pesticide List are allowed. There are other EAMU approvals, but they are not safe for borage or leave high residues, so therefore are not suitable for some of the end markets (e.g. those producing for baby food).

Mr Boughton says sclerotinia has been under-reported a lot in borage, as the sclerotia and the borage seed are very similar in colour and size.

Borage is extremely susceptible if the weather conditions are right at the time the crop is emerging and if there are spores around – it’s not only susceptible during owering, as it’s a later emerging crop and doesn’t respond like OSR does at owering only.

With mildew, the key advice is to treat it very early or lose control –there is no curative active for mildew in borage. There are some approved chemicals for mildew and sclerotinia which have to be used fairly early in the life of the crop, but the only alternative to protect against mildew after the early owering stage is elemental sulphur. Ammonium thiosulphate-type liquid products do not prevent mildew; only elemental sulphur is e ective.

Pre-em metazachlor products are recommended, at a rate of no more than 1-litre/ha in total. However, do not apply if heavy rain is forecast as it is highly soluble in water so can impact the seed.

Do not use chlopyralid products as they cause a hormone-type damage which results in distorted owers, no pollination and no seed set.

Centurion Max type graminicides now have an EAMU for use in borage.

In terms of the timing for swathing, Peter Fairs says this needs to begin “the day before the plant is losing more seed than it is making”, which should occur roughly 7–10 days after the rst seed drop.

It’s important to look properly at the canopy – the top may look ready for harvest, but the underneath may be less mature in comparison so Peter Fairs says don’t be afraid to hold back and lose some at the top as this will preserve the seeds still being made further down.

However, if you have hot weather and a less dense canopy with fewer side branches, you probably need to act more quickly.

In order to ensure successful swathing, it begins with the drilling – pre-drilling, elds should be level and rolled, and obstacles such as manholes and large rocks/stones should be avoided at drilling to prevent machinery damage at swathing. FG