Growers should keep a watching brief on crops – but avoid rushing in, says Richard Overthrow
January can still hold opportunities for drilling if required – either late winter crops or early spring varieties.
If you find yourself eager to plant early spring crops, remember this will not necessarily lead to better crops, it is purely a logistical measure. Next month is plenty early enough to be seriously thinking about spring crop drilling.
With last autumn being not too dissimilar to the previous one, many winter cereal crops will have been sown but not treated with pre-emergence herbicides, due to limited opportunities. Many growers will therefore be relying on contact products such as Broadway Star, or for blackgrass Hamlet or Atlantis.
These should be applied sooner rather than later before target weeds become too large so look out for suitable weather windows to get them on as soon as is practical. Better spray opportunities may arrive later but this usually means weeds are bigger and harder to control.
If the target weeds are known, spring germinators such as meadow brome however, some delay may be necessary to allow the weed population to appear.
Reports of mildew and yellow rust in wheat were common last month. If insufficient cold weather has occurred, these diseases will still be around. If present, they need watching though should be treated only if absolutely necessary – if the life of the crop is threatened. Hopefully we can address these infections with a T0 fungicide, although this is a long way off.
In some areas winter wheat sowing continued into December so once again there will be a number of late developing or backward crops that will need careful management. But although late sown and backward cereal crops will need fairly prompt first nitrogen applications in order to discourage tiller loss, they won’t respond to anything applied this month. It is unlikely that ground conditions will allow top dressing anyway, but any nitrogen applied so far ahead of the start of spring growth will be wasted.
Many oilseed rape crops have established and grown well so should be examined to determine canopy size, with a view to future fertiliser management. If still large and three-dimensional as the first nitrogen timing approaches, the total nitrogen applied should be reduced from the usual 200-plus kg/ha nitrogen. Some crops will have no such concerns, however, with canopies that are plenty small enough.
There may also still be outstanding applications of propyzamide or carbetamide to be applied to oilseed rape. If there are any treatments still to go on, cut-off for Kerb (and Astrokerb) is the end of January, and for Crawler the end of February.
Rape crops may still show fresh infections of phoma, however any infections developing now are unlikely to affect yield as there won’t be sufficient time to form stem cankers.
Any mild and wet periods from now on may encourage light leaf spot however, so further treatment for this, at or even before stem extension, cannot be ruled out – even if autumn treatment was applied.
Richard Overthrow is a regional agronomist with NIAB TAG, the UK’s largest independent agronomy organisation with several research centres in East Anglia. For more details, call 01223 342495.