Prioritise profit and quality in the face of wet harvest conditions
Date: 23 Nov 2020
Forecasts for a wet harvest period in some cropping regions should have growers preparing to harvest profitable crops and good quality seed as a priority.
Wet conditions prior to or during harvest can cause seed to germinate which reduces starch and protein and results in downgrading.
It can also affect germination for grain kept for next season, potentially hampering future crops.
Experts are also reminding growers to be aware of the long-term damage machinery entering wet paddocks can cause to soil structure.
The likelihood of a wetter than normal harvest was recently confirmed with the Bureau of Meteorology (BOM) forecasting a La Niña weather event, predicting a wetter than average spring and summer.
The last La Niña event affected Australia from 2010-2012 and according to BOM, it resulted in one of Australia's wettest two-year periods, but conditions this year are expected to be less extreme.
Strategic harvesting
Growers experiencing a wet harvest are encouraged to adapt their program to harvest next season’s seed requirements or more profitable crops as a priority.
This may involve strategic harvesting of paddocks, or areas of paddocks, with well-draining soil types while waiting for paddocks to dry out or grain moisture levels to decrease.
It could also require growers to target small areas of each crop type to harvest the seed required for next season before continuing their usual program.
HRZ Ag Consulting adviser Chris Bluett said the scenario that could bring grain quality down would involve prolonged wet periods which did not allow crops to dry out.
He said prioritising the harvesting of crops from a quality and pricing perspective to protect profits and next year’s seed was a safe option.
“If harvest ends up wet, the most important thing is to get the grain off as any delays can cost you quality and money,” Mr Bluett said.
“A wet harvest can result in black point-type diseases in the grain, as well as discolouration and a reduction in quality — the ultimate of that is sprouted grain, which is of relatively low value.”
Grains Research and Development Corporation (GRDC) Southern Region Panel member and agricultural consultant, Jon Midwood, said targeting crops, such as malting barley or white wheats that will suffer from a quality perspective from wet conditions, should be the priority.
“Potential delays can turn these crops to feed quality very quickly, making for an expensive downgrade,” he said.
“Canola growers could avoid damage in wet conditions by opting to windrow onto stubbles instead of direct heading.
“This would dry the crop for harvesting more quickly than waiting for a crop to ripen in a direct heading scenario.”
Seed testing and storage
Mr Midwood said any seed retained for next year’s cropping program that is affected by wet conditions at harvest should be tested for quality and possible germination.
He said seed testing grain intended for sowing would inform more accurate sowing rates of partially germinated seed and detect seed-borne diseases.
“Seed testing is a very small cost in the scheme of things and can offset future losses as a result of not sowing seed at the optimum density,” he said.
Mr Midwood said visual assessment of discolouration was not a reliable indicator of grain quality issues.
“Falling numbers often occurs without visual indication and is a sign that the germination process has started in grain,” he said.
“If growers have any concerns about their grain, or they’ve sent grain to a receival site and there were issues with falling numbers, then the writing is on the wall that germination has started.”
The GRDC Retaining Seed Fact Sheet advises ongoing monitoring of stored grain, particularly if it is subjected to adverse weather conditions at harvest.
Maintaining low temperatures, humidity and grain moisture content is critical as weather damaged seed deteriorates faster than sound seed in storage.
Helpful tips for maintaining seed quality are also available on the GRDC Stored Grain Information Hub
Soil structure preservation
Mr Bluett, who is also vice chairman of the Australian Controlled Traffic Farming Association (ACTFA), said growers adjusting harvest plans in wet conditions should also consider paddock trafficability.
“If the harvest period looks like it’s going to be wet, growers need to look at their planning more carefully and they may be forced to harvest a particular paddock because it’s the first one dry enough to take machinery onto,” he said.
Mr Bluett said controlled traffic farming (CTF) practices where growers have designated compacted wheel tracks had an advantage in a wet harvest scenario.
“The benefit of controlled traffic farming is growers can potentially harvest again sooner, once grain moisture levels allow, as there are compacted tracks to drive on.
“Getting machines such as headers and chaser bins bogged in waterlogged soils can cost growers time and make a mess of the paddock.”
Mr Bluett said moving to CTF could be a consideration for growers in areas prone to wet harvest or water logging.
CTF restricts all heavy machinery wheels to permanent traffic lanes where compaction is beneficial for paddock access. However, CTF adoption requires autosteer and a planned machinery replacement and/or modification program to convert equipment to full CTF dimensions over a period of years.
The GRDC Controlled Traffic Farming Fact Sheet outlines a number of positive outcomes for growers considering adopting a CTF system.
CTF can improve grain quality and increase grain yields by two to 16 per cent (10 per cent is a common average after the year of establishment) if there are no other limiting subsoil constraints
Mr Midwood said damage to soil structure from machinery getting bogged in wet ground was a “hidden cost” that could impact future crops.
“It may not be front of mind for many as harvest is typically a dry time of year where the soil strength can maintain the header above the ground,” he said.
Mr Midwood said filling in holes cause by bogged machinery could cosmetically fix the problem, but the disturbance to soil layers had the potential to affect crop growth into the future.
More information
Chris Bluett, HRZ Ag Consulting
0409 336 113
chris.bluett@hrzconsulting.com
Jon Midwood
0400 666 434
jon@techcrop.com.au
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