Swathing and harvesting operation
Swathing involves cutting the crop and placing it in rows held together by interlaced straws, supported above the ground by the remaining stubble.
The crop can be swathed in any direction but is usually cut across the sowing direction or at a 45 degree angle for crops with a wider row spacing. This allows the swath to sit up better on the stubble. Swathing is not recommended for paddocks where the crop row spacing is over 25 centimetres (cm).
Avoid placing swaths in the same location each year. Adjust to distribute the residue across the paddock so nutrients etcetera are not concentrated in one place.
Swather size or width of cut should match header capacity. A double-up attachment to the swather or placing two swaths side by side requires a larger capacity header and concentrates the residue in a narrow band within the paddock.
The cutting height must be adjusted to allow for sufficient straw on the head to keep the swath together (minimum 30cm) and sufficient stubble height to support the wind-row. It is recommended to start the swath height at 10-20cm above the ground (one-third height of crop or beer can height) and then adjust to produce an even swath with well-interlaced straws that sit above the ground, allowing good air circulation and rapid drying should rain occur.
When the swath is picked up, the reel should be rotating slightly faster than ground speed, but not so fast that heads are knocked off the stems. The conveyor canvas should be revolving sufficiently fast so that it does not clog with crop material. Rows pick up best when following the header follows the direction of the swath (heads first).
If the crop is too thin or the stubble too short to support the swath above the ground, the crop should not be swathed. Heads on the ground may sprout and attempts to pick up heads that are lying close to the soil surface will pick up soil.
Harvesting of the swathed crop must be completed as soon as possible, ideally within 10 days of swathing. If swaths are left too long and are subjected to long periods of wetting (more than 25 millimetres (mm) of rain over 4-8 days), grain may sprout and become stained and may become contaminated with bronze field beetle. Following extensive rain, some growers have attempted to turn or fluff the swaths using a rake or hay baler with an open back door. There has been mixed success with this practice, particularly with heavy swaths. Many growers have reported in hindsight that it would have been better to not have touched the swath row and picked up as normal.
One of the major sources of contamination in swath barley is when the stubble is torn out during the swathing operation. This generally occurs when the swather is operated at too high a ground speed or when trying to swath when the straw is tough due to it being cool or damp.
Acknowledgements
This information comes from the Barley production in Western Australia site, first compiled by Roslyn Jettner and Pam Burgess from contributions by officers of the Department of Primary Industries and Regional Development then updated in 2006 by Richard O'Donnell, Alaina Smith and Blakely Paynter.