A blast of rain following a long dry spell is likely to result in significant nitrogen (N) mineralisation which will help drive a burst of growth. If your crop is just emerging, this will push out big green leaves and tillers. If it is at the early tillering, this growth will drive more tillers and big leaves. These can be considered useful growth responses for generating yield potential in spring barley in particular.
But if you are moving into stem extension, the response to a burst of soft rapid growth could be less desirable. And if you happen to have higher levels of soil mineral N following the relatively dry and mild winter, then you may have reason to be concerned about lodging risk.
As stated last week by John Spink and Joseph Lynch, anything that increases stem density and growth rate can reduce stem strength and thus increase lodging risk. This is a seed rate and tillering issue and is influenced by the natural straw strength of a variety, the amount of N applied early, the total amount of N applied, total available N and when that N becomes available to the crop.
So crops that are dense at the end of tillering, especially those with high N availability, can be very prone to stem breakage and lodging and this is even worse when rapid growth accompanies stem extension. For all of these reasons, lodging must be assessed in individual fields.
Some fields that got rain three weeks ago after N application should have this N available now. Individual fields had more or less growth during tillering and this influences the risk. Other fields had no rain since N application, so the bulk of the N will only become available now.
Lodging is not totally predictable so an appreciation of the variables stated is essential for a grower to assess the possible need for plant growth regulation.
Treatment
While my preference might be to avoid growth regulation use on spring barley due to the sensitivity of this crop, there will be times when circumstances conspire to make it necessary and this could be one of those years.
A crop that does not look excessively dense today does not mean zero lodging risk. If you have a lot of N applied, coupled with high soil mineral N, then your risk is high if your stem count is adequate, or higher. This could mean that PGR would be beneficial and should be considered, especially on certain varieties. Lodged crops are a no-no!
In the past, it was common for growers to wait until the last minute, when they were sure that the crop was likely to lodge, to decide to use a PGR. And generally that involved late application of either Terpal or Cerone, which acted more to shorten the plant rather than strengthen its base.
So lodging could still occur where these PGRs were applied late and late tillering could be an unintended consequence where lodging occurred.
Where a crop is rated low on standing power – varieties like Propino, Planet, Overture, Olympus and especially Laureate – PGR should be considered at early stem extension to try to strengthen the base of the stem which is most likely to be the cause of lodging. Treatment and timing will depend a bit on the risk factors involved, when other inputs are being applied and the actual condition of the crop.
If a crop is very high-risk, then one should consider a split treatment at early and late stem extension, which could well coincide with fungicide application. If the risk seems less critical, then a single treatment around GS31/32 might be targeted. Timing might also be influenced by what you use.
Product options
CCC: This and other CCC derivatives are often applied to spring barley crops, but, in my opinion, they are more to enhance tillering than to provide a solid basis for growth regulation or lodging prevention. Indeed, I have often seen such treatments acting to enhance lodging because they can be so successful at increasing stem density when used properly. These products can be used, but do not assume that you have applied an anti-lodging agent.Trinexepac-ethyl: This includes products like Farmco PGR, Freeze, Limitar, Moddus, Moxa, Optimus and Trinexis. These are generally used in conjunction with CCC and the combination provides both shortening and strengthening of plant stems. The latest timing is GS33 so these products generally lend themselves to a single application. This timing would be late for a crop with high lodging risk. Optimus has a lower concentration so a higher rate is needed. These tend to be used at 0.1l/ha in conjunction with CCC (75%) at 1.0l/ha at GS30/31. Also containing trinexepac is Medax Max and this also contains prohexadione calcium. This is new to the market but it can be applied on spring barley up to GS39 and so it enables a split application. It claims a fast and slow reaction for its different ingredients and so may have a more prolonged activity in the plant. A split application should target GS29/30 followed at GS33/37 using about 0.25 kg/ha with possibly less in a second application if that is necessary.
Terpal: An old but successful product and often used in the past at later timings when lodging risk was perceived to be high. Such timing may be too late for any product to be successful. Because it contains ethylene it does exert stress on a crop and this can result is considerable late green tiller production, especially if the crop fails to stand. This is a significant risk when waiting for this timing. But it can provide a significant improvement in shortening and standing power when applied earlier. Apply prior to awns emerging at the latest.Cerone: Not allowed on any spring crops. Read more
Spring barley nitrogen and lodging
A blast of rain following a long dry spell is likely to result in significant nitrogen (N) mineralisation which will help drive a burst of growth. If your crop is just emerging, this will push out big green leaves and tillers. If it is at the early tillering, this growth will drive more tillers and big leaves. These can be considered useful growth responses for generating yield potential in spring barley in particular.
But if you are moving into stem extension, the response to a burst of soft rapid growth could be less desirable. And if you happen to have higher levels of soil mineral N following the relatively dry and mild winter, then you may have reason to be concerned about lodging risk.
As stated last week by John Spink and Joseph Lynch, anything that increases stem density and growth rate can reduce stem strength and thus increase lodging risk. This is a seed rate and tillering issue and is influenced by the natural straw strength of a variety, the amount of N applied early, the total amount of N applied, total available N and when that N becomes available to the crop.
So crops that are dense at the end of tillering, especially those with high N availability, can be very prone to stem breakage and lodging and this is even worse when rapid growth accompanies stem extension. For all of these reasons, lodging must be assessed in individual fields.
Some fields that got rain three weeks ago after N application should have this N available now. Individual fields had more or less growth during tillering and this influences the risk. Other fields had no rain since N application, so the bulk of the N will only become available now.
Lodging is not totally predictable so an appreciation of the variables stated is essential for a grower to assess the possible need for plant growth regulation.
Treatment
While my preference might be to avoid growth regulation use on spring barley due to the sensitivity of this crop, there will be times when circumstances conspire to make it necessary and this could be one of those years.
A crop that does not look excessively dense today does not mean zero lodging risk. If you have a lot of N applied, coupled with high soil mineral N, then your risk is high if your stem count is adequate, or higher. This could mean that PGR would be beneficial and should be considered, especially on certain varieties. Lodged crops are a no-no!
In the past, it was common for growers to wait until the last minute, when they were sure that the crop was likely to lodge, to decide to use a PGR. And generally that involved late application of either Terpal or Cerone, which acted more to shorten the plant rather than strengthen its base.
So lodging could still occur where these PGRs were applied late and late tillering could be an unintended consequence where lodging occurred.
Where a crop is rated low on standing power – varieties like Propino, Planet, Overture, Olympus and especially Laureate – PGR should be considered at early stem extension to try to strengthen the base of the stem which is most likely to be the cause of lodging. Treatment and timing will depend a bit on the risk factors involved, when other inputs are being applied and the actual condition of the crop.
If a crop is very high-risk, then one should consider a split treatment at early and late stem extension, which could well coincide with fungicide application. If the risk seems less critical, then a single treatment around GS31/32 might be targeted. Timing might also be influenced by what you use.
Product options
CCC: This and other CCC derivatives are often applied to spring barley crops, but, in my opinion, they are more to enhance tillering than to provide a solid basis for growth regulation or lodging prevention. Indeed, I have often seen such treatments acting to enhance lodging because they can be so successful at increasing stem density when used properly. These products can be used, but do not assume that you have applied an anti-lodging agent.Trinexepac-ethyl: This includes products like Farmco PGR, Freeze, Limitar, Moddus, Moxa, Optimus and Trinexis. These are generally used in conjunction with CCC and the combination provides both shortening and strengthening of plant stems. The latest timing is GS33 so these products generally lend themselves to a single application. This timing would be late for a crop with high lodging risk. Optimus has a lower concentration so a higher rate is needed. These tend to be used at 0.1l/ha in conjunction with CCC (75%) at 1.0l/ha at GS30/31. Also containing trinexepac is Medax Max and this also contains prohexadione calcium. This is new to the market but it can be applied on spring barley up to GS39 and so it enables a split application. It claims a fast and slow reaction for its different ingredients and so may have a more prolonged activity in the plant. A split application should target GS29/30 followed at GS33/37 using about 0.25 kg/ha with possibly less in a second application if that is necessary.
Terpal: An old but successful product and often used in the past at later timings when lodging risk was perceived to be high. Such timing may be too late for any product to be successful. Because it contains ethylene it does exert stress on a crop and this can result is considerable late green tiller production, especially if the crop fails to stand. This is a significant risk when waiting for this timing. But it can provide a significant improvement in shortening and standing power when applied earlier. Apply prior to awns emerging at the latest.Cerone: Not allowed on any spring crops. Read more
Spring barley nitrogen and lodging
This is a subscriber-only article
SHARING OPTIONS: