When those seeds germinate the plants are nearly always bolters too, and so the problem escalates exponentially every time a fodder beet or similarly long-season, spring-sown crop is grown.
What’s more, beet seeds remain viable in soil for decades so can sit there for years under pasture or autumn-sown crops, only emerging when the next beet crop is grown.
Brown said that growers would be wise to nip bolter problems in the bud by routinely removing them before seed is set.
“If you haven’t drilled too early and got a whole field of them then very little time is required.”
Seed Force’s David Walsh had already warned the field day crowd of the risk of sowing too early, saying mirroring the United Kingdom’s earliest safe sowing dates such as British Sugar’s March 5, which corresponds to September 5 in this country, isn’t appropriate because of NZ’s much more variable climate.
Also, UK safe sowing dates are for sugar types whereas most of the NZ sowings are fodder lines that haven’t had the same breeding focus over the years to reduce bolting risk.
“Other companies have come out with one or two years’ data and said it’s fine to sow from September 1. In our view that’s very risky,” Walsh said.
SeedForce has trials in Central and mid Canterbury, north Otago and Southland investigating the effect of sowing date on yield and other crop characteristics, such as bolting. Each trial is fully replicated with multiple cultivars and six sowing dates, starting September 14 in mid Canterbury.
While a paper on the work has been submitted for November’s Agronomy Society Conference in Timaru, conclusions wont’ be drawn until several years’ data provides reliable trends, Walsh said.
Seed shed from bolters can render paddocks unfit for fodder beet in the future.
Long-time beet grower and dairy farmer Brendon Wood regards fodder beet “as the new grain” for his 1000-cow herd near Burnham.
“Grain’s out for us and personally I can’t see it coming back,” he told the SeedForce field day.
“We’re going to use more beet and that’s totally related to cost and return on investment.”
That’s despite having in-shed feeding for grain available. Feeding lifted beet through a standard silage wagon, or grazing in-situ beet was just as simple and Wood said that as a feed it is “the next best thing to grass”.
“We’ve found [high-drymatter variety] Suga will keep well. We’ve started digging it in May and kept it windrowed through to January-February.
"It doesn’t look very palatable by then – in fact it looks terrible, but Jim [Gibbs] has done the work and the feed quality has hardly altered at all.”
Wood he said he was buying fodder beet at the moment at just under 30c/kg delivered and with well-grown crops consistently yielding 25 tonnes drymatter (DM)/ha in his area, it represents a win-win for cropping and dairy farmers alike.
“I can see that it could be traded quite readily and give the cropping farmer another option with a good result for both parties.”
Unlike kale or swedes the entire beet plant is high quality – 12 megajoules of metabolisable energy/kg DM feed – and near 100% utilisation even in winter was no problem, he added.
“I don’t know anything else you can do that with.”
And it’s not just for the South Island either, SeedForce’s James White added.
“I think the biggest potential for harvested beet in NZ is actually in the North Island as a high-energy supplement to pasture.”
KEY POINTS
The Brits’ better fodder beet tips include:
- Sow slowly and early into dry, not compacted seed bed
- Keep drill points sharp to cut uniform-depth V, not U-shape
- Fungicides pay but none are cleared for NZ use
- Very little virus seen in NZ to date so aphicide use is questionable
- If lifting, machines require meticulous set-up and operation
- Do not wash if windrowing
- Minimum one-in-four rotation
- Zero-tolerance to bolters.
