Hyper-yielding cereals, commonly found in New Zealand and Tasmania, could be the future for Western Australias southern grain-growing regions.
But, according to Agronomy Focus consultant Quenten Knight, greater investment in breeding cultivars with shorter vernalisation periods is needed to find varieties that suit the southern WA climate.
Mr Knight and a group of growers and agronomists recently returned from a GRDC-invested tour of New Zealands Canterbury Plains, an area that regularly receives 600 millimetres of annual rainfall.
During the tour, they investigated the management strategies involved in producing hyper-yielding cereal crops.
Hyper-yielding wheat crops in the Canterbury Plains grainbelt can achieve yields of up to 16 tonnes per hectare, although more commonly the average yields are about 10 to 12t/ha.
The group met barley and wheat yield world-record holders Warren Darling and Eric Watson. Warren and Eric achieved those records using irrigated systems, although Warren grows most of his cereal and canola crops under a dryland system.
Obviously an irrigated system for cereals isnt practical for WAs broadacre cropping systems, but meeting with these growers was an inspiration and gave the tour group some food for thought, Mr Knight says.
On the Canterbury Plains, long-season or winter wheat varieties are planted in April and harvested in January. Many hyper-yielding crops in New Zealand are irrigated over the summer months.
Obviously an irrigated system for cereals isnt practical for WAs broadacre cropping systems, but meeting with these growers was an inspiration and gave the tour group some food for thought
Mr Knight says growers in some higher-rainfall regions in WA are already trialling long-season or winter varieties in an attempt to see what might be possible.
Some growers in Esperance and Albany have achieved yields of almost 8t/ha.
But hyper-yielding crops are still in their infancy in WA.
While we already have a few winter wheat varieties that growers in our region are testing, such as Bennett, Longsword (PBR) and Illabo (PBR), this tour highlighted the urgent need to see greater investment in breeding varieties that have a reduced vernalisation requirement to accommodate the shorter finishes in these parts, Mr Knight says.
In some of our trials, flowering and grain-filling can still be occurring in late October and November, which, while suitable for New Zealand, is way too late in our region.
Mr Knight says any new varieties must have the ability to flower in September, despite being planted in late March.
A hyper-yielding cereal system would suit growers who have invested in soil amelioration practices and have flexible nutrition and fungicide strategies, he says.
Water use efficiency in these higher-rainfall WA growing zones is currently relatively low, at 5 to 6 kilograms/ha/mm for cereals, and there were opportunities to improve this to about 20kg/ha/mm.
What this means is that there is huge potential in these regions to improve yields if we can get more suitable varieties and can get the agronomy packages right, Mr Knight says.
Nicky Tesoriero, also from Agronomy Focus, says the tour highlighted the key management strategies needed to achieve high-yielding cereals, particularly early planting, extra nutrition and proactive preventive foliar disease management.
These long-season crops need to be planted into moisture in March or early April to ensure the plants have enough time to experience a vernalisation period over winter, she says.
One key difference between a spring wheat variety and a winter wheat variety is that during periods of stress, or drought, in the early part of the season, a spring variety will race away into a reproductive phase, while a winter variety wont move into this reproductive phase until it has experienced a certain period of cold temperatures.
There is huge potential in these regions to improve yields if we can get more suitable varieties and can get the agronomy packages right
Ms Tesoriero says growers on the tour understood the need for hyper-yielding crops to receive extra nutrition, including more regular and timely nitrogen applications, and often at least three to four applications of fungicide.
What we saw in New Zealand was a big increase in the number of fungicide applications on these crops often up to four different applications through the growing season. As a result, the crops achieved a 20 to 40 per cent increase in yields, she says.
On average, most southern WA high-rainfall zone spring cereal crops will receive only one or two fungicide applications, so this is a major management change.
She says mixing up modes of action would be critical for growers considering an increase in fungicide applications.
What we dont want to see is an increase in yields with a corresponding increase in fungicide resistance. This strategy would need to be managed very carefully, she says.
Mr Knight says while yields might be higher, producing these crops is also significantly more expensive given the extra management involved.
Growers and their advisers need to work closely together to develop a management plan for incorporating these crops into their rotations, he says.
Following the groups return from New Zealand, a '10 Tonne Club' has been formed. This will include a yield record program and promote grower and adviser discussion to help implement tour learnings.
GRDC Project Code: GAD9175698
More information: Quenten Knight, quenten@agronomyfocus.com.au