High rainfall croppers are continuing to push the yield frontier, with a 11.48 tonne a hectare wheat crop winning GRDC's Hyper Yielding Crop Awards for SA.
It was among several 10t/ha-plus cereal crops harvested in the Lower South East earlier this year, which had benefited from the mild conditions during flowering and grain fill.
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The RGT Accroc crop grown by Tom Bell, Millicent, was not only the highest yielding in the competition, but also won the highest percentage of potential yield category, smashing the 10.5t/ha predicted, based on a soil moisture and solar radiation formula.
Receiving the award on Monday, Mr Bell attributed the doubling in yields in the past decade to the agronomic research being conducted at FAR Australia's SA Crop Technology Centre.
"It has certainly come a long way, with average wheat yields of 5-6t/ha 10 years ago to 10t/ha and more today," he said.
He said identifying longer-season varieties at the Crop Tech Centre had been a "game changer".
"Historically, we weren't getting much funding going into potential germplasm out of Europe," he said.
"But having the hyper yielding site, we have been able to have research specific for our niche environment down here.
"There are a couple of other varieties coming through that look pretty exciting for yield and we may not need to go as hard on the fungicide program, as they look to have better disease resistance."
The winning crop was sown in mid-May last year, with 120 kilogram/ha of MAP into a paddock, which had grown canola in 2021.
Prior to sowing, 150kg/ha of single super was broadcast onto the paddock and about 190kg/ha of nitrogen was applied throughout the growing season as urea and sulphate of ammonia.
"We had a wet July and there was a lot of water lying around, but things dried out well following that wet period and then we had timely rains through spring," he said.
Mr Bell said they often grazed their cereal crops to fill a feed gap window for their livestock, but had instead used a plant growth regulator with their first fungicide application at growth stage 31 in August.
The crop, which had 620mm of growing season rainfall, had two more fungicides applied - one at flag leaf and another at flowering to protect it against septoria and other diseases.
The paddock produced 25t/ha of dry matter, which was measured just ahead of harvest on January 20.
The grain sample had a 79.98kg/hL test weight and 9.5 per cent protein.
"It made the headers work, but it was not a big, tall, leggy crop. It put a lot of energy into filling out the heads," Mr Bell said.
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He said it was nice to be recognised in the HYC Awards, but said it was not an individual win but a "team effort" with all their staff playing a role.
"The biggest thing for me is that everyone in the (HYC) group all shares a lot of information and we are able to help each other learn and see the trial work out in everyone's paddocks," he said.
"I don't think we will be going from average yields of 10t/ha to 15t/ha (wheat crops) in the next few years, like where we have come from, but there may be a bit more room for some smaller yield gains by tackling some of our soil constraints.
"This was only one paddock in our program. It would be nice to see overall wheat yields average of 11.5t/ha and with everything going the right way, it is a real possibility. However at the end of the day, our results are dictated by climate and various seasonal factors beyond our control."
HYC project officer Jen Lillecrapp says the awards are a great way to measure and acknowledge the big yields being achieved, although the biggest motivator for many was the chance to benchmark their crops and agronomic practices against other growers.
"The more paddocks and seasons in the data set allows us to establish good benchmarks, which are specific to the high rainfall areas," she said.
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"This will provide growers and agronomists a guide. So for example, we will understand the key timings of crop inputs, biomass at harvest and the number of heads per square metre to target for growing high yields."
She said many growers had made quantum yield leaps in their wheat, but were using the benchmark data to determine the next management strategies that may help them to make small but incremental gains.
The average yield of the top 20pc of crops, which were all Accroc, was 11.16t/ha, while the remaining 80pc averaged 8.91t/ha.
Mrs Lillecrapp said there was not a huge difference in the nitrogen applied between the crops entered because growers applied slightly more nitrogen than in the previous year, as it was off the back of high yields in 2020 and it got reasonably wet in winter.
"We had a lot of waterlogging and the crops were under a lot of pressure," she said.
"They didn't look showy, but we didn't have frosts or extreme heat and, even though we didn't have a lot, the rain was at the right time so we had that soil moisture."
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Mrs Lillecrapp said Mr Bell's attention to detail and applying adequate inputs at the correct time had all played a role in the win.
"Tom has refined and followed a recipe for success, which included choosing a suitable variety, good weed control, adequate nutrition and applying a growth regulator and fungicides at the right times, which kept the crop standing and clean and greener for longer," she said.
