July 26, 2012
Prepare for Major OSR Establishment Challenges
Serious delays to the cereal harvest and persistently cold, wet soils brought about by one of the wettest summers on record mean oilseed rape growers across the country need to prepare themselves for a particularly challenging establishment season, believes Agrii OSR specialist, Philip Marr.
“The unbelievable wetness and lack of sunlight so far this summer means cereal maturity is already a good two weeks behind where it should be,” he points out. “And, if soils stay as waterlogged as many have become, we could well see the same sort of harvesting difficulties and delays we had in 2007.
“The wheat harvest is unlikely to start until well into August for most. Which means a large amount of OSR won’t be able to go in until September, much of it considerably later in the month than many growers will be used to. What’s more, seedbed conditions are shaping-up to be far from ideal, even before any soil damage from harvesting.
“Under these circumstances, the viability of next year’s OSR crop will, more than ever, depend on growers’ ability to ensure their establishment agronomy is up to the challenge.”
In this respect, Philip Marr identifies three key essentials:
- Using varieties that can cope with later drilling into less-than-ideal seedbeds;
- Sowing them in bands at the right seed rate with a single pass system; and,
- Providing them with sufficient early nutrition support.
“Our extensive trials suggest that more than half the varieties available today are insufficiently vigorous or too slow in their initial leaf development to be reliably sown after the first week of September,” he stresses.
“In general, hybrids seem to have greater establishment vigour than pure-lines. As many have found in recent years, though, plenty of hybrids aren’t fast enough in leaf development for sowing at this time. Especially not under questionable, cold and wet seedbed conditions and with slugs promising to be hyper-active.
“Faster-developing hybrid varieties with a particularly high biomass – courtesy of the extraordinarily mild winter and wet, windy spring – appear to have been more prone to root lodging than some in the past season,” he observes. “But, like 2007, I certainly wouldn’t be without them for the coming one.
“In my experience quite a few current varieties are safe to sow into the start of September and there are seven – all hybrids – I’d be happy to drill well into the month. Of these, only two are fast enough developing to recommend prioritising for sowing beyond mid-September – Excalibur, which really showed its superiority in 2007, and newly recommended DK ExPower from the same stable. So I’d want a good proportion of varieties like these in my mix.”
Alongside the most vigorous and fastest-developing hybrids, Mr Marr is adamant that single pass sowing in wide rows following deep tines has to be the preferred establishment system for this season’s conditions.
The fact that most growers will be critically short of seedbed preparation time gives single pass sowing a huge edge. At the same time, he sees deep tine working as vital to tackle the particular soil slumping and compaction risks of the season, adding that sowing in 45-55cm rows takes maximum advantage of the local cultivating effect of the tines and their value in moving excess water away from young roots.
“You simply must get your seed rate right,” Philip Marr insists. “Make sure you sow by seed number rather than weight to account for major differences in 1000 seed weight. If you’re sowing in rows, adjust the rate to achieve the right plant population in the row. And don’t be tempted to increase it too much because you’re sowing later or to offset slug problems. Or you could easily end up with crops that are too dense for their own good.
“Given the conditions, you’ll need to support your OSR establishment with the best possible early nutrition too,” he adds.
“If continued wetness and lack of sunshine means relatively low September soil temperatures poor nitrogen mineralisation will make seedbed N particularly important. It will also be vital to apply extra phosphate or potash in bans at sowing wherever P or K indices are below 2.
“With the extent of phosphate demand for root development, I wouldn’t be sowing anything without the specialist seed treatment, Take-Off this autumn either. And I’d be including phosphite-based, Nutriphite PGA in any early winter spray to further promote rooting which could easily be badly compromised by the cold, wet conditions.
“The coming autumn will be far more challenging for OSR than the last one,” concludes Philip Marr. “We may even get a winter too. I have no doubt whatsoever that harvest 2013 success will fundamentally depend on establishment regimes that are able to rise to this challenge.”