A new benchmark has been set for mainland grain producers, with growers in one of South Australia’s smallest cropping regions reaping colossal wheat yields of more than 11 tonnes per hectare.
Tom Bell, who farms with his wife Lucy and father Greg at Emerald Farms, near Millicent in the state’s south-eastern corner, harvested 11.48t/ha of RGT Accroc wheat in January.
That dryland crop in Lang’s Paddock took out both of the SA awards – for highest yield and highest percentage of yield potential – in the second annual GRDC Hyper Yielding Crops initiative.
Tom says he had intended to graze the paddock, but the wet winter and waterlogging made that impractical. Instead, plant growth regulators were applied in August and the crop returned 109.33 per cent of potential yield, which had been estimated at 10.5t/ha.
Photos of the crop taken two weeks before harvest show a solid expanse of wall-to-wall heads, which were measured at 659 per square metre and averaged 34 grains each.
Well-suited winter wheat variety
Tom attributes the astonishing result to a combination of seasonal conditions, timely applications of crop inputs and having access to a winter wheat variety suited to the region’s environment.
Popular in France, RGT Accroc is a dual-purpose, red, medium-long growing season winter wheat with potential for high yields in high-rainfall zones.
Tom’s award-winning crop was sown on 14 May 2021 into a paddock used for canola the previous year and broad beans in 2019.
The crop grew a lot of biomass, thanks to the 150 kilogram/ha seeding rate and opening rains in April that provided a timely start to the season.
It was a pretty mild spring, and we had timely rainfall events, but it wasn’t excruciatingly hot, which was good for flowering and grain fill.
Significant rainfall events from late April until the end of October included the wettest July on record and contributed to 620 millimetres of growing-season rainfall. Rainfall for 2021 totalled 740mm, just shy of the annual average of 750mm.
“A drain alongside (Lang’s Paddock) ran water all winter, so I had no way of getting stock into this block, hence I didn’t end up grazing the crop,” Tom says.
“It was a pretty mild spring, and we had timely rainfall events, but it wasn’t excruciatingly hot, which was good for flowering and grain fill.”
After deciding not to graze the crop because of the wet conditions, Tom applied a mix of the plant growth regulators Moddus Evo and Errex to reduce the risk of lodging and improve efficiency when it was harvested on 20 January.
MacKillop Farm Management Group Hyper Yielding Crop project officer Jen Lillecrapp says the result has lifted everyone’s expectations and the benchmark.
“It wasn’t that many years ago – maybe five years – when we thought we were doing well if we got 6t/ha or 7t/ha,” Ms Lillecrapp says.
“When we started the local MacKillop Farm Management Group back in the late 1990s, based on rainfall the formula calculated that we should be growing 10t/ha cereal crops. Growing 10t/ha was a vision for the group but we all thought it was an aspirational target. None of us actually ever dreamt that we would do it ... it really has been phenomenal to see growers achieve this 10t/ha target.”