HIGH rainfall zone (HRZ) grain producers have only scratched the surface of their potential cropping achievements.
Average HRZ yields could conceivably go close to doubling in the coming decade, according to Victorian Department of Primary Industries (DPI) HRZ agronomist Penny Riffkin.
Ms Riffkin, based at Hamilton in Victoria's rain-blessed Western District said using existing simulation models, 120 years of historical climate data and detailed site specific information, it was clear yields could be much higher.
"Given the average amounts of radiation and rainfall and factoring in the soil type, it is not unreasonable to estimate average yields of nine tonnes a hectare," she said.
"It could be closer to 10t/ha for cereals here at Hamilton where annual rainfall averages almost 700 millimetres.
"This is well up from today's average yields of perhaps four to five tonnes/ha.
"But even if we were less ambitious with estimates, with good varieties specifically targeting high rainfall zone, we could comfortably see yields rise by 25-50pc."
She said good yield increases were possible for all HRZs - areas recording above 500mm annual rainfall.
Even though drought stress, as well as waterlogging, could be a problem in areas with annual rainfall of 500 to 550mm she said trials had consistently yielded "above the control" potential there.
While Australian high rainfall areas were a different environment to similar rainfall zones in Britain or New Zealand, overseas croppers routinely harvested much higher yields than were being achieved in Australia.
"I don't think Australian farmers will be chasing 15t/ha plus yields, because of the risks associated with such big expectations, but by managing the cultivars specifically for the environment we can make big improvements," Ms Riffkin said.
She is involved in a Victorian DPI project designed to help boost HRZ yields through a combination of improved varieties and management techniques.
The most crucial gains would be in the development of specific varieties suited for the area.
"We need to work on a wheat plant that will work here," she said.
At the moment we've either got UK germplasm, suited to a different set of conditions and a different growing season, or varieties designed for more traditional, drier wheat growing areas.
"Although we have high yield potential, in Australia, even in the HRZs, we are still confronted with terminal drought in the spring and frost at flowering, which need to be factored in when considering suitable varieties," Ms Riffkin said.
There was scope for development in all of Australia's high rainfall zone cropping areas, such as Western Australia's south western tip, south eastern South Australia, Tasmania and NSW's southern slopes, but said there would be different drivers in each area.
"We will need varieties to suit each area, for instance in WA's HRZ, farmers face a shorter season and have a much higher risk of frost," she said.
Ms Riffkin said the focus did not need to be on high yielding feed lines.
"There is interest in better quality wheats and the breeders are looking at these," she said.
"I don't see why we can't get high yields with high quality."