November 21, 2016
Iain Richards Blog: Patience pays in wheat and OSR management
Once again, late wheat drilling is paying handsome black-grass management dividends. But, with such a dry autumn, it’s been a matter of holding our nerve well into the second half of October.
We didn’t drill our worst black-grass fields until the last week of the month. Which means the crops are only just coming through while our late-September drillings on lower risk ground are already well-tillered.
Thank heavens we held off as long as we did, though. It was mid-October before a lot of our black-grass found sufficient moisture to grow and, even then, we only secured decent flushes to glyphosate-off where stubbles were moved and consolidated after harvest.
As a result, many crops going in before the 20thof the month in our area emerged with far too much weed growth. What’s more, the dryness got in the way of both pre-em activity and seedbed consolidation. So, seriously beefed-up peri-ems with extra contact activity have been needed, really adding to the cost.
In contrast, where we got our cultivations right and waited for enough soil moisture we were able to eliminate a good amount of black-grass before drilling, achieve much better seed-to-soil contact and make the most of our pre-ems.
Although these crops are well behind as temperatures drop away, there’s plenty of growth left in the sort of seasons we’re seeing these days. And we’ve used quality Deter-dressed seed from fast-developing varieties; upped seed rates to compensate for lower tillering; taken particular care to stay on top of slugs from the outset; and will be prioritising early spring fertilisation and plant growth regulation.
With this sort of management we’re confident late-sowing will reward us yet again this season. Especially so in limiting both black-grass losses and herbicide costs, as well as saving on the follow-up BYDV spray we’re currently giving our earlier-drilled wheats to combat active aphids, and taking the early pressure off our disease management.
Thankfully, the dry autumn has kept the lid firmly on disease development. Even our earliest sown wheats are going into the winter nice and clean. Equally, we’ve been able to hold off on any OSR fungicides well into November, employing combinations of prothioconazole and tebuconazole targetted primarily at early light leaf spot control with growth regulation, where necessary.
We’re not combining this with propyzamide, though. Instead, we’re waiting for soil temperatures to fall further and crops to lose enough leaf for the best persistency and soil coverage. Holding off on Centurion Max until the last two weeks of October has worked incredibly well for us this season, taking any urgency out of the first class black-grass control that is a key priority for us.
Interestingly, we’ve seen some significant patches of clubroot in our OSR for the first time ever this autumn. Maybe the dry conditions have prevented our liming being as immediately effective as usual ? Or maybe it’s a worrying sign for the future and we’ll need to be thinking more about resistant varieties ?