Trial reveals salt effects

Recently released data from a 2009 paddock trial in Ballidu has highlighted the importance of selecting the right crop type and variety to maximise yields on salt-affected land.

Project leader Tim Setter, of the Department of Agriculture and Food, said barley yields outperformed wheat yields by an average of 50 per cent, and up to 100 per cent in some cases.

“The best wheat varieties were only as good as the worst barley varieties,” he said.

“This surprised me. While barley is known to yield better in saline soils, I had expected some of the wheats would be just as good as the best yielding barley varieties.”

Dr Setter said there were also up to two-fold differences in yields within both wheat and barley.

Australian breeding companies, pre-breeding groups and individuals contributed 120 wheat and 56 barley varieties, including commercial varieties and breeding lines, to be screened at the saline, alkaline (7.5 to 9.5pH) site.

Dr Setter said it was the first time so many cereal varieties and lines had been tested in an Australian field trial for their performance in saline conditions, alongside the same varieties grown in non-saline conditions.

“The data from the trial will lead to new strategies that cereal breeders and pre-breeders can use to produce better yielding varieties,” he said.

“The trial showed there is a great capacity to improve production on salt-affected soils simply by knowing the production potential of particular varieties on this type of land.”

Dr Setter said the top three traits identified for high wheat and barley yields on saline soils were early flowering/maturity; boron tolerance and salinity tolerance at the germination and establishment stage.

“Trial results suggest that wheat could produce 25 per cent higher yields simply by reducing the days to flowering by five days, and increasing boron tolerance from 5 to 20 per cent,” he said.

“Similar results could be achieved for barley.”

Dr Setter believed earlier flowering and maturing cereals performed better in the trial because soil salinity was higher at the end of the season, and low in the middle of the season.

Salinity was equivalent to 100–150 per cent seawater at the start and end of the season and lower in the middle of the season at 20–50 per cent seawater.

Soil salinity measurements were supported by new techniques used by researchers from the University of WA.

This ‘transient’ salinity — typical of salt-affected sites in WA’s grainbelt — was due to more rain being received in winter.

“Barley is much earlier flowering than wheat and I believe this is partly why it produced yields on average 50 per cent higher than wheat in the Ballidu trial,” Dr Setter said.