Skip to content

Legume workshops highlight cropping issues

A series of workshops across central and southern NSW has highlighted the soil conditions that impact on the nodulation of legumes.

More than 150 landholders and agricultural advisors attended six workshops that were coordinated jointly by Central West, Central Tablelands and Riverina Local Land Services to address ways to improve legume nodulation and nitrogen fixation.

Senior Land Services Officer - Mixed Farming, Dr Belinda Hackney from Central West Local Land Services said recent surveys had shown more than 90 per cent of paddocks sampled through the Central West and Riverina had inadequate levels of nodulation.

”Survey results suggest that farmers are missing out on the nitrogen these legumes can contribute to other pasture species or crops following the pasture phase” Dr Hackney said.

Dr Sofie De Meyer, a rhizobiologist from Murdoch University in Western Australia, spoke to workshop participants about factors that can affect nodulation and stressed the importance of acidity on the process.

“Where soil pH is too low, legumes aren’t able to grow well and there are also direct effects on the survival of rhizobia - the bacteria responsible for nitrogen fixation,” Dr De Meyer said.

”About three-quarters of all the paddocks sampled in the survey had soil pH levels that would affect nodulation in annual clover,” Dr Hackney said.

The situation was worse for lucerne and annual medics, with up to 90 per cent of paddocks recording pH levels that would negatively impact nodulation.

Dr De Meyer also discussed research at Murdoch University investigating the impact of some commonly-used herbicides on legume growth and nodulation.

”Our research has shown that some group B herbicides in particular have a huge impact on root growth and nodulation,” Dr De Meyer said.

“These herbicides are used commonly for weed control in both crops and pastures so landholders and advisors need to be mindful of how this might affect legume performance.”

Workshop participants, including David Tod of Forbes, described the workshop as invaluable, while one Dubbo-based agronomist reporting he had already implemented strategies from the workshop with his clients to improve production.

“My legumes look very healthy above ground, but below ground it is a different story,” Mr Tod said. “I now understand why this may be and I have some tools to address the problem”.

Surveys taken during the Forbes workshop showed a dramatic shift, with an average score on knowledge of factors affecting nodulation and nitrogen fixation on a scale of 0 to100 36 before the workshop and 71 after.

Participants also recorded a score of 78 when asked how likely they were to implement changes in the management to improve nodulation.

Follow-up field days and workshops covering these issues will be held in regional areas in coming months. For details, visit the events page on your regions Local Land Services website.

ENDS

Media contact: Fiona Townsend on 0428 284 252 or via email: Fiona.townsend@lls.nsw.gov.au