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Managing disease and nitrogen content in spring barley

Agronomy Issues
01.05.2020

Get grain nitrogen content right

Achieving the correct grain nitrogen content is crucial for malting barley. As a rule of thumb, malt distilling requires grain N below 1.65% and higher nitrogen is required for grain distilling varieties such as Fairing which require a minimum of 1.85% but can benefit from going higher. Always check your contract if you have one and adjust fertiliser regimes according to the variety and field situation.

Growing Laureate for distilling in Scotland

When growing Laureate for malt distilling with lower grain N, less total nitrogen should be applied. In this case, trials showed nitrogen fertiliser could be increased to 125 kg/ha to raise yield without exceeding the 1.65% grain N threshold, but if increasing to 150 kg/ha, then % grain N became more marginal. Timing-wise for malt distilling, we would typically suggest either a split application with at least half in the seedbed or applying it all in the seedbed. If you still have an application to make to your Laureate crop we recommend this goes on by GS13 to avoid significant increases in grain N. If you’re used to growing a lower-yielding variety that doesn’t dilute its grain N as much, you may find you have flexibility to apply more nitrogen with Laureate.

Growing Fairing for grain distilling in Scotland

If aiming for higher grain N with Fairing, hold back some of your nitrogen to apply later in the season to ensure it is not diluted. As crops are now coming through the ground it is important to think about how to feed the crop going forward. High nitrogen is key for grain distilling use in order to break down the starches of non-malted cereal grains into sugars. A three split programme has proved effective with roughly 40% in the seedbed, 40% at GS13 and the final 20% to be applied between GS30-49 to boost grain N, dependent on soil moisture. 

Manage disease correctly

Having sufficient fertile tiller numbers to produce the optimum number of ears per square metre provides the foundation for yield in barley – so it is important to protect tillers by creating a disease-free, healthy canopy early on. Later, it becomes important to protect grain-filling by maintaining this clean and green canopy as the season progresses.

With this in mind, it is often better to apply two fungicide applications (or potentially three in some circumstances), even if at lower doses, to maintain green leaves all the way up the canopy, rather than trying to control disease in one ‘hit’, especially as the lower leaves in barley contribute more to yield than in wheat.

As well as the usual diseases of Rhynchosporium, net blotch and mildew, brown rust has been prevalent in barley over recent seasons, and Scottish growers will need to be especially vigilant against Ramularia with the loss of chlorothalonil this year.

Elatus Era for spring barley

The SDHI-based fungicide Elatus Era is a very good fit in barley. As well as being fully approved for use in malting barley and providing activity against key diseases of net blotch and Rhynchosporium, it gives exceptional brown rust control. It also delivers a robust dose of SDHI for the money and contains the triazole fungicide prothioconazole, which is well-recognised in barley.

Trials with Elatus Era used once in a two-spray fungicide programme have shown excellent responses in spring barley.

From an ease-of-use perspective, it can also be used in both barley and wheat.

Ramularia

Chlorothalonil can only be used up until 20 May 2020, which will almost certainly be before the usual spring barley T2 timing.

In anticipation of the loss of chlorothalonil, we have evaluated the alternative multi-site fungicide, folpet. Trial plots in spring barley showed that adding folpet to Elatus Era at T2 gave a positive yield response in a Ramularia situation.

Example fungicide programmes in spring barley

 

T1

T2

T3

Full Programme

<GS30:

SDHI/strobe/triazole

GS37-39:

Multi-site*

GS49-55:

Elatus Era

High risk Ramularia

<GS30:

SDHI/triazole + multi-site*

 

GS45-49:

Elatus Era + multi-site*

Low disease,

“single shot”

 

GS37-39:

Elatus Era + multi-site*

 

* Multi-site = CTL or Folpet

Since spring barley grows quickly, it is important to monitor crops regularly to be timely with fungicide sprays. As in other cereals, disease prevention is better than cure.