June 9, 2014
Placing extra priority on early OSR agronomy
Maximising oilseed rape establishment and early growth must be particular priorities this autumn in the absence of neonicotinoid seed dressings, growers were advised at the specialist AgriiFocus OSR Day earlier this month.
“Getting crops up and running as rapidly and strongly as possible will be a priority to counter the greater flea beetle pressures many will undoubtedly be facing now we can no longer use Modesto, Cruiser or Chinook,” stressed Agrii agronomist, Greg Taylor. “At the same time, it will be valuable in coping with slugs, pigeons, early phoma infections, weed infestations and challenging winter conditions.
“Importantly, studies we’ve been conducting at Brackley and our other iFarms across the country in parallel to R&D trials at our Agrii Technology Centres highlight a host of valuable opportunities for improving OSR establishment.”
Foremost amongst these are choosing vigorous fast-developing varieties; sowing them at the right seed rates into the best possible seedbeds; and providing effective early nutritional and root development support.
Alongside, these, of course, Greg Taylor sees timely post-planting treatment to counter early threats from slugs, weeds, phoma and both flea beetle and aphids as important components. And he notes that the option of mesurol treated hybrid seed imported from France could also be valuable.
Citing pioneering Agrii work on autumn development rates, he pointed out that some varieties develop far more vigorously and rapidly than others. While hybrids tend to be better in this respect than pure lines, he insisted that there are important differences between hybrids in their speed of autumn development, in particular, which need to be taken into account in variety choice.
“High seed rates are especially important to avoid with faster developing hybrids,” he added. “We almost invariably see these types performing better at sowing rates of 50 seeds/m2 or less. “While the lowest rates may be too risky for many in case conditions are less kind than the past autumn and winter, the last thing I’d advocate in response to the neonic ban is increasing seed rates. This could easily do more harm than good by producing over-thick and poorly-structured canopies wherever establishment conditions prove less challenging.
“More often than not the peak of cabbage stem flea beetle activity is in mid-late September, so it’s important to have a crop growing strongly at this stage. Having said that, we know that crops sown into fine, firm and moist seedbeds in the first half September establish better than those put into dry or cloddy conditions in August. So seedbed conditions should always be more important than calendar date in choosing the best time to drill.
“Seedbed nitrogen is something we’ve found to be valuable in getting crops off to the best start too,” reported Greg Taylor. “Especially so, where minimum tillage means little or no release of soil nitrogen, incorporated crop residues may restrict its availability and organic manures haven’t been applied. Where crops are being drilled in bands, applying N only within the sown band is a good way of getting sufficient onto the crop while keeping within N-Max.
“Equally, our work shows that double rolling can really help ensure the good seed-to-soil contact so important to rapid germination and root development. It’s also extremely valuable in preserving soil moisture, restricting slug activity and supporting pre-em herbicide activity.”
Agrii studies also show a specialist nutritional seed dressing like Take-off or an early foliar application of Nutriphite PGA or Quark can give a noticeable boost to crop establishment and early growth too. While this may not have a major impact on performance where flea beetle levels are low, it could make all the difference in allowing crops to survive serious infestations.
“It’s just another example of the many opportunities we have for integrated agronomic improvement, concluded Greg Taylor.
“The neonic ban is wholly unjustified by science and extremely unwelcome. However, if it stimulates the right sort of extra emphasis on key aspects of oilseed rape establishment agronomy, dare I suggest it could prove a blessing in disguise; in much the same way that increasing black-grass resistance is leading us to develop altogether more integrated, robust and sustainable approaches to managing this problem weed.”