Western Australian wheat growers could look to lucerne to help boost wheat yields based on latest research by the Department of Agriculture, Western Australia.

Department researcher Perry Dolling said the results of a three year trial at Borden heralded the benefits of lucerne to the wheat phase.  The research was supported by the Grains Research and Development Corporation and the CRC for Plant Based Management of Dryland Salinity.

Mr Dolling said the research investigated whether the benefits of lucerne increased with ongoing use in rotations.

Lucerne was sown in 2001 at three kilograms per hectare in plots that had lucerne in the previous pasture phase.  Lucerne was also sown in ‘virgin’ lucerne plots, following annual pasture to simulate a first-time grower. These were both compared to the performance of annual pasture in rotation.

Lucerne was removed in late 2003 and then all treatments were sown to wheat in 2004.

“The trials found that wheat yields increased by 10 per cent, but protein was slightly lower by 0.5 per cent in wheat following lucerne compared to wheat following subterranean clover,” Mr Dolling said.

“There was no difference in wheat yields between one or two phases of lucerne.

“The previous pasture phase has shown lucerne also used 40-100 mm more soil moisture than annual legume pasture to 180 cm depth and therefore reduces the input of water into the groundwater system. This will have benefits in terms of reducing the spread of salinity and waterlogging,” he said.

“The lucerne produced similar biomass to annual pasture, or in years of significant summer rainfall, was more productive.”

Mr Dolling said lucerne controlled weed populations over the long-term due to physical competitiveness and the ability to tolerate some non-selective herbicides.

He said tolerance to non-selective herbicides would assist in reducing the build up of herbicide resistant weeds.

“The ability of the lucerne system to reduce the weed population and, in some seasons, contribute more nitrogen to the soil can benefit following wheat crops,” Mr Dolling said.

He said the establishment and productivity of lucerne in the first year of the second phase was improved due to reduced weeds after the first phase of lucerne.