De-Risking the Seeding Program

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IFN Trial Results March 2024 - De-risking the seeding project
Early sowing can have many advantages and the key driver of success is variety selection to enable flowering to occur in the preferred window regardless of sowing date.

Earlier sowing with the correct variety allows a longer vegetative period, leading to more biomass and greater grain yield. Its important to remember that the flowering window is the same for early sown or later sown crops. For us it is late September into mid-October for wheat and slightly earlier for barley, too early and our frost risk increases; too late and the risk of heat stress rises. Varieties have differing vernalization requirements as is shown in our early sown wheat variety trial. We have a significant spread of flowering dates from the one sowing date.
key messages
With early sowing you still need to pick the right variety and sow in the right window, so you don’t have frost issues in spring.
Sowing earlier may require pre-irrigation in most seasons, so a decision needs to be made on whether the cost of the water is justified. As always, way risks and potential rewards of irrigating and calculate expected returns.
Pre-irrigation can give certainty to emergence dates, give an even germination and help minimize the risk of winter drought if you have seasonal restrictions on access to water. Adversely, it can result in waterlogging risk if we get a very wet winter and create a big bulky crop that will need more water come spring.
The characteristic of some slower maturing or winter cereals means they are slower to reach maturity and so may need an extra irrigation in late spring.
The Rewards
The longer vegetative period of early sown cereals offers the opportunity for grazing. Grain yield is not compromised by grazing with good management correct growth stage, grazing intensity and allowing sufficient time, moisture and nutrition for recovery.

Another advantage of early sowing is that there is the opportunity for sowing rates to be reduced. As the vegetative period is longer, there is the potential for more tillers to be produced. Be wary as reducing sowing rates can result in more weeds due to reduced crop competition and warm conditions at sowing that facilitate weed growth.

An observation from the IFN early sown versus main season variety trials is that some varieties benefit from being sown early due to disease developing later in the plant’s lifecycle. An example of this was the 2019 wheat trials that saw DS Bennett and Trojan yielded 3.5 – 4 t/ha better from the earlier sowing due to escaping the worst of stripe rust by being more mature and had already accumulated most of their grain fill needs by the time stripe rust had removed the green leaves.

Early sowing can help with managing seeding logistics as operations can be spread over a longer period.
The Risks
The more biomass is more yield can come unstuck when this leads to lodging, issues with grain fill and harvesting difficulties. If you’ve created big bulky canopy you may need to consider applying a PGR.

Early sown, highly vegetative crops may run out of soil moisture faster than later sown crops and need irrigating earlier in spring, which may be before the season opens. A trial at the IFN Trial Block in 2019 saw moisture stress set in in late July and the plants responded by shedding tillers. This loss in yield potential was not recovered when the trial was eventually irrigated in mid-August. The characteristic of some slower maturing or winter cereals means they are slower to reach maturity and so may need an extra irrigation in late spring.

Sowing very early can result in poorer germination due to soil temperatures that are too warm. No definitive data is produced to identify the varieties susceptible but IFN trials have shown some oats and wheat to have poor germination when sown in early March.
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This project is a result of a successful application to the Australian Government's Future Drought Fund's
- Extensions and Adoption of Drought Resilient Practises Grants Program