The first split of nitrogen (N) should be applied to winter barley crops, as a matter of priority, according to Teagasc.
The recommended application rate is at 50kg/ha with the main split applied by growth stage 31 (GS31). On thin or backward crops, the first N is an absolute priority.
But application rate should be low as crop demand is also low. Sulphur (15kg/ha) and deficient trace elements (based on soil analysis and field history) should be applied before GS31.
Growers should use Moddus/Medax Max plus 1.0L/ha CeCeCe for high lodging risk fields at GS30.
To get the best straw shortening effect in barley, Cerone/Terpal/Moddus/Medax Max should be applied from GS32- 39.
It is now too late to control annual meadow grass in crops that did not receive a herbicide last autumn. Where a tidy-up is required after an autumn herbicide, growers should use a sulfonylurea/Zypar/Galaxy/Hurler, etc., depending on weeds present.
Active growth and high rates are needed to control overwintered weeds.
Spraying winter crops
Teagasc is confirming a number of thin winter wheat crops this season. Where grass weeds are present Pacifica Plus/Monolith plus Biopower are options.
Broadway Star plus Torpedo is a strong brome option, where annual meadow grass has already been controlled.
Growers should avoid crops under stress and be careful of tank mixes.
The first application of approximately 50% of the total N requirement should be applied to winter oat crops by GS30 (early- to mid-March).
Where no autumn herbicide has been applied, crops should be treated with a sulfonylurea (Cameo Max/Ally Max) and a suitable partner to match the weed spectrum.
Pixxaro and Zypar at 50% rates are now approved for winter oats. The most successful plant growth regulator (PGR) strategy in Teagasc trials is a two-split approach with the first application at GS30/GS31, followed by a second application at GS32.
The second application will have a greater shortening effect. PGRs should only be applied when there is active growth; avoid frost and large tank mixes.
There are large variations in green area index (GAI) in oilseed rape crops this season.
As a consequence, there are large savings on N in crops with large canopies. So growers should avoid early application and high N rates, as excessive N will result in a reduction in yield. A GAI of less than 1.0 will require 225kg/ha.
The first split should be applied as soon as growth commences. In contrast, a crop with a GAI of 2.0 will only need 130kg/ha and the first split can be delayed until mid-March.