Minimising Head Loss in BarleyHarvest Declaration Form

August 7, 2014

All barley varieties will drop heads prior to harvest if certain conditions apply. It is true however to say that some varieties are more prone to head loss than others. For some varieties, the use of a growth regulator such as Modus Evo® is advised, to reduce the risk of losing heads. Growth regulators  – when applied at GS30 – shorten the crop height and increase the cell wall thickness. A growth regulator is not usually required with Westminster grown on the mainland, unless the crop is looking as though it could be at risk (eg: a heavily tillering canopy with high N reserves and above average yield potential).

There are certain things that can be done to reduce the risk of your barley variety dropping heads.

  1. Keep your nitrogen application under control. Too much nitrogen can increase the crop canopy and may reduce the thickness of the cell wall. A reduced cell wall thickness may contribute to stem breaking late in the season, particularly of the crop experiences high winds. Too much nitrogen can also significantly increase the height of the crop with the result that the head can move more in the wind increasing the risk of stem breakage
  2. A frost or significant check to the crop may increase the amount of late tillering. This can cause the crop to have heads at different maturities. If you wait for the latest heads to mature many of the early heads can be over-ripe with the result that these early heads can break away. Make sure that you know at what moisture content you can deliver barley and harvest when the crop is ready.
  3. In a highly risky crop it may be worth investigating the option of windrowing. This does add another cost however it may be worth considering. A 5% loss of heads in a 6 Tonne/ha crop worth $250/T, amounts to a loss of $75/ha.
  4. Armyworms are often the culprit when it comes to heads on the ground. Make sure that you regularly check your crop for these pests from head emergence onward.
  5. Potassium is critical in maximising straw strength and it is also crucial in water movement throughout the crop. A crop deficient in Potassium will not be as drought resistant and it may not have the same straw strength as a crop with an ample supply of Potassium. This element has possibly been overlooked for many years throughout the Western Districts, so it may be worth undertaking a tissue test in the crop to assess the levels.

Consult your agronomist for further information. GrainSearch aims to undertake some research into Potassium levels in barley this year.