Growers in South Australia and Victoria have been equipped with greater knowledge to increase nitrogen fixation by their pulse crops during workshops in June.

The 'Boosting on-farm nitrogen fixation in pulses' workshops featured presentations on the latest research into inoculation techniques, while also discussing factors relating to inoculation - including dry sowing, acid tolerance, chemicals, soil types and the effectiveness of new and existing rhizobia strains.

Workshops were held at Kimba, Cummins and Adelaide, in South Australia, and Swan Hill, in Victoria, with about 80 growers and advisers attending.

Researchers from Primary Industries and Regions SA's research division the South Australian Research and Development Institute (SARDI), Dr Liz Farquharson and Ross Ballard, as well as independent consultant Dr Maarten Ryder, shared their insights at the workshops.

Attendees also heard from a local agronomist on region-specific issues regarding crop management to maximise nitrogen fixation benefits.

SARDI senior research officer Dr Liz Farquharson says topics covered included general inoculation practice, dry sowing, acid soils and inoculant compatibility with pesticides.

"A key component of the workshops was an interactive hands-on session where participants could inspect plants for adequate nodulation," Dr Farquharson says.

"Prior to the workshops, growers and advisers were encouraged to dig up some pulse plants with as much of the root system as possible and bring them along to the workshops to assess early nodulation.

"This included providing a guide on how to assess crop nodulation, including when and how to sample."

All workshop participants received copies of the GRDC's back pocket guides 'Inoculating Legumes: A Practical Guide' and 'Inoculating Legumes'.

Key discussion points arising from the workshops were:

• The impact of seed dressing chemicals on rhizobia survival;
• The difference between peat and granule inoculants; and
• The impact of suboptimal conditions on rhizobia survival.

Research conducted by SARDI has shown that increasing the rate of inoculant applied as peat slurry to seed improves nodulation where conditions at sowing are suboptimal, for example, in dry or acidic soils.

Researchers have identified rhizobia strains with improved acidity tolerance and have been testing the best strains in the field since 2015.

The performance of new rhizobia strains for faba beans and lentils across a number of scenarios has been encouraging and there are good prospects for commercialisation, according to researchers.

Growers and advisers who missed out on the June workshops have another opportunity to learn about unlocking the full potential of nitrogen fixation at additional workshops to be held in South Australia and Victoria in September and October.

These workshops are an initiative of the GRDC investment 'Increasing the effectiveness of nitrogen fixation in pulse crops through extension and communication of improved inoculation practices in the southern region'.

The project's partners are:

• Mallee Sustainable Farming;
• Bates Ag;
• Rural Directions;
• Southern Farming Systems;
• Birchip Cropping Group;
• Moodie Agronomy;
• Riverine Plains;
• SARDI-PIRSA;
• Trengove Consulting;
• Ryder Ryan Research; and
• AgCommunicators.

More information: Belinda Cay, AgCommunicators, 0423 295 576.