Teagasc crops specialist, Shay Phelan, has assessed the field work required for winter barley and wheat crops in the coming days and has said that one chemical in the spray tank is likely to be enough.
He has also looked at the fertiliser requirements of late-sown spring cereals.
Most winter barley crops have received their final nitrogen (N) at this stage with the first fungicide treatment, so all that is left now is to apply a growth regulator and a final fungicide.
As many of the crops out there this year have limited yield potential for various different reasons, there will be no benefit in applying any extra fungicide when a growth regulator is being applied over the coming days.
Winter barley
The Teagasc representative said: “Some farmers and agronomists are allergic to only putting one chemical into a tank to do a single job. This is often the case when something like Terpal is being applied on winter barley.
“There seems to be a need to put something else in the tank to justify travelling through the crop, but in this case, and especially in 2024, it is rarely warranted.”
Growers should be aware that KWS Joyau is very forward and probably needs a plant growth regulator (PGR) as soon as possible – awns will probably be visible by the end of next week.
The final fungicide should be applied at the awns peeping stage, according to the advice from Teagasc.
Phelan continued: “Repeated trials have shown that by delaying for two weeks allows ramularia to infect the crop and will reduce yield by anything up to 0.4t/ha.
“This will more than cover the cost of the fungicide. Growers should include folpet at full rate but only 50% rate of an azole/SDHI/Strob mix will be fine.”
Winter wheat
Leaf 3 will be emerged on many of the early-sown wheat crops over the coming days. From the evidence of Teagasc monitor crops, there may well be septoria reported on lower leaves, which will spread up the plant.
Graham does have some yellow rust, so growers should be on the watch out for that.
Diseases to be on the lookout for right now in winter wheat crops are: Septoria; yellow rust; eyespot; and mildew.
Growers who are unsure if Leaf 3 is fully emerged, dissect the plants and count the leaves starting with the flag leaf (Leaf 1).
Spring cereal drilling
Many growers are continuing to drill spring cereal crops at the moment. The following question is regularly asked – how much N should be incorporated into the seedbed?
Crops take up nitrogen by growth stage, so the majority of nitrogen uptake will still take place after Growth Stage 30.
Putting a higher proportion in the seedbed will help if a dry period follows sowing, but there is a risk of N losses if heavy rain follows. Applying N when the tramlines are visible is a compromise.
Total N for feed crops should be based on yield potential. Growers should use sowing date and establishment percentage as a guide.
E.g., a 6.5t/ha crop has a requirement of 135kg/ha on index 1 soils. Growers should add an additional 20kg/ha for every tonne expected over 6.5t.
N rates for brewing barley should be reduced, equivalent to expected yield reduction when compared to a normal sowing date.
Distilling, however, is likely to be a real challenge with late-sown crops in 2024.
A 20kg N/ha reduction from malting rates is generally recommended. In other words, if the recommendation was 120kg of N/ha, then applications should reduce to 100kg.
High levels of unprotected urea will cause ammonia scorch and should be avoided.