RESULTS of a Tasmanian irrigated wheat project, aimed at pushing productivity and profitability boundaries of feed grain cereals, has relevance to other parts of Australia's high rainfall zone (HRZ), including Western Australia, according to Foundation of Arable Research (FAR) Australia managing director, Nick Poole.
Mr Poole, who led the Hyper-Yielding Cereal (HYC) project in collaboration with Southern Farming Systems, said although the research took place in Tasmania, a location that had a longer season and was cooler than the HRZ of WA, the same principles could be applied to some WA regions.
He spoke at the Grains Research and Development Corporation (GRDC) HRZ workshop at Dandaragan recently.
Over the past three years the irrigated HYC research centre at Hagley, Tasmania, used more than 1000 experimental research plots each year to identify new cereal lines and agronomy strategies that could lift feed grain productivity in the Tasmanian HRZ.
The research concept was to explore whether the April sowing window could be used to maximise biomass and yield potential without giving rise to large increases to input costs.
"The largest lever pulled in agronomy in the past 10 years is the sowing date," Mr Poole said.
"While we can't take advantage of it every year, the sowing date is one that challenges the germplasm we currently have, since April sowings may require us to look at winter germplasm rather than spring.
"In addition, earlier makes our disease resistance and our standing power a lot more important."
So far, results from the five-year project, funded by GRDC, have set new benchmarks for the yield performance of irrigated feed wheat, with plot yields in excess of 16 tonnes per hectare in 2016, 12t/ha in 2017 and 13t/ha in 2018.
Following the success of germplasm identified in the project, research has been conducted on similar germplasm in South Australia's HRZ to examine whether any of the same principles hold true.
Results in 2018 from the South Australian Crop Technology Centre at Millicent, run by FAR Australia in collaboration with SARDI and funded by Landmark, suggested there is relevance of the HYC research to the mainland high rainfall zone.
Mr Poole said longer season European cereal germplasm and Australian bred winter wheat cultivars were performing well in the long season HRZ of southeast South Australia and Victoria, as well as Tasmania, when sown in mid April.
"The same lines identified as high fliers in Tasmania have been performing well in South Australia's HRZ," Mr Poole said.
"Winter wheat cultivars were more suitable to secure the yield potential of mid-April sowing than spring wheat, which developed too quickly.
"The spring wheat cultivars were subject to significant frosting, particularly where cultivars were left ungrazed.
"There was a benefit to grazing the spring wheat, since grazing effectively reset the plants time clock so that key development periods were delayed until later in spring, when it was more in tune with the season."
Through the collaboration of international, national, local expertise and breeders, the project is using links with end users to promote the value of trading quality feed grains.
"Some of the varieties we want might already be out there, to bring in from overseas," Mr Poole said.
"But on occasions that's more difficult with winter lines, since the system of bringing germplasm into Australia is more geared to spring germplasm than winter."
The projects results showed in order to generate higher yielding cereal crops it was essential to generate high harvest dry matters.
"This has been clearly observed in HYC and South Australian research, with the more promising cultivars producing the higher dry matter content at harvest," Mr Poole said.
"Cultivars that combine higher final harvest dry matter with a high harvest index are the lines we are looking for.
"In addition to higher dry matter and harvest index, the same cultivars require better disease resistance and standing power."
High yield potential was strongly linked to higher fertility in the research project, with the extra nitrogen required provided by the soil, not additional fertiliser.
"I think there is a limit to how far the artificial fertiliser can take us," Mr Poole said.
"From our research on wheat, there's evidence you don't get higher yields from just more and more bagged nitrogen.
"A common theme we've found is we're not able to get a yield response to applications of applied nitrogen of over about 225 kilograms of nitrogen (N) a hectare, despite crop canopies containing an estimated 350-400kg N/ha at harvest.
"Sure, we're under doing artificial fertiliser in the high rainfall zone, but bagged nitrogen will only take us so far in the push for very high yields.
"You also need an underpinning restorative soil fertility in the farming system itself on which that artificial nitrogen is applied."
