Local growers report a yield ceiling in oats, unlike barley, suggesting...

Local growers report a yield ceiling in oats, unlike barley, suggesting a challenge in achieving higher grain yield. This may stem from higher biomass and a source-sink imbalance, making oats more vulnerable to environmental stress. Last season’s trials support this, showing excessive nitrogen reduced harvest index and grain weight, ultimately lowering yields—likely due to increased biomass and greater susceptibility to terminal drought (data available on request).

Further reinforcing this, trials showed significantly higher yields when oats were planted in late March instead of late April, suggesting early seeding helps mitigate drought effects. Overseas research also links vegetative indices (multispectral analysis) at panicle emergence and early grain fill to final yield, suggesting these indices could serve as a tool for identifying unrealized yield potential.

By comparing up to 3 milling oats varieties that with difference in phenology and crop architecture this research will seek to address the following issues:

* Maximise oat yield, quality and profit through efficient use of nitrogen.

* Provide insights into the relationship between time of sowing, biomass growth, nitrogen application, and grain yield in oats.

* Identify whether variety specific characteristics offer opportunities to overcome the yield ceiling.

* Identify the risk (lack of photoperiod hold) or benefits (grain yield) with early seeding of varieties.

* Use multispectral technology to improve decision-making tools for growers.

* Contribute to sustainable oat production by addressing yield limitations associated with excessive vegetative growth, terminal drought, and over-fertilization.

Trials are to be applied to farmer-sown strips of up to 3 milling oats varieties that with difference in phenology and crop architecture (4 randomized replicates within each block). A range of environments to capture N response & rainfall/terminal drought influence: 1. Low Rainfall (Lake Grace): 4N rates, 2 TOS, 3 varieties (96 plots) 2. Medium Rainfall (Narrogin): 4N rates, 2 TOS, 3 varieties (96 plots) 3. High Rainfall (Williams): 5N rates, 1 TOS, 3 varieties (60 plots)