June 23, 2016
Making the most of this season’s OSR potential
The vast majority of our winter oilseed rape has come to the end of flowering as we move into June, although some more backward crops badly ravaged by pigeons in the cold March have hang on longer than we’d like, says Agrii agronomist Harry Abell.
Even these are developing into well-structured, pod-rich canopies, though. So we have plenty of potential in a season where maximum output will be more important than ever.
We’re mainly growing HOLL rape these days – V295OL and V316OL – as the output is every bit as high as ordinary ‘double lows’ and the premiums especially valuable. So they make perfect sense wherever we can secure the right contracts.
These and the DK Exalte we’re also growing a decent amount of have been easy to manage through to flowering, in marked contrast to another leading hybrid (which shall remain nameless) that has been the very devil to keep clean from both phoma and light leaf spot.
Apart from this problem variety, low phoma development meant we were able to hold off on fungicide spraying until November, using a single autumn spray to target early light leaf spot risks while encouraging rooting with timely plant growth regulation. This has been especially valuable in a winter of such persistent wetness and LLS pressure.
Although we had no flea beetle problems whatsoever, the very vigorous establishment of V295OL, in particular, also paid dividends in keeping our rape ahead of serious slug problems through the mild, wet winter. And DK Exalte’s especially vigorous spring growth has proved invaluable with March turning so cold and pigeons becoming so problematic.
Where we didn’t have sufficient varietal resistance, we had to go in with an early March LLS fungicide two weeks ahead of our stem extension spray. We didn’t want to have to do this, but we simply couldn’t afford to wait. This has really underlined the importance of first class resistance to light leaf spot as well as phoma in our variety selection.
This season has also underlined the value of both variable seed rates and the specialist PGR, Toprex at early stem extension in producing the sort of well-branched and structured canopies we want for the 5t/ha yields we’re targeting.
From around 40-50 seeds/m2 overall and just 20-30 seeds on better ground we’ve achieved some very nice even plant populations. And Toprex has given us very obvious advantages in branching without any signs of hotness to the crop.
With the sort of crops we have, we’re going to need serious patience with our desiccation timing. It’s easy to be tempted to go in with the glyphosate too early. But to give the crops the greatest opportunity to bulk up and put on vital extra oil we’ll be holding off until the pods on the lower branches are good and ready rather than dashing in as soon as those on the main raceme have reached the right stage.
After all, this is where our crops are carrying the bulk of their yield and we know the pods here invariably ripen later than those at the top.
Yes, there’s always the worry that we’ll lose some seed from further up the plant. With the pod shatter resistance we have in most of our crops and the pod sealant we use as a matter of course, though, we’ll be well insured against this. So we’ll be able to capture the potential we have built into our crops to the very maximum.