Bacteria saving you a tonne

A single packet of bacteria inoculant added to a summer crop can provide as much nitrogen as one tonne of urea — at less than 1 per cent of the cost, according to CSIRO Plant Industry researcher Bob Gault.

Mr Gault said legumes needed the bacteria (rhizobia) in their root zone to fix nitrogen. Field trials with inoculant showed the bacteria could produce between 200 and 300 kg of nitrogen per hectare for pulses.

Mr Gault said the inoculant could be used on the seed through the seed box or delivered directly into the furrow.

"You have to be sure that you have the right sort of rhizobia for your crop — the type of inoculant you need varies from crop to crop and region to region. Growers should check with their district agronomist," Mr Gault said.

Figures released by NSW Agriculture indicate that, nationally, $300 million worth of nitrogen (about 270,000 tonnes of fertiliser) is available to farmers with effective inoculation.

"Nearly all of the nitrogen (around 80 per cent) currently sustaining cereal cropping comes from past nitrogen fixed from the air by the rhizobia bacteria on the roots of legumes," said Jeff Evans, NSW Agriculture microbiologist.

Dr Evans said the Australian Inoculant Research and Control Service (AIRCS) provides quality assurance for approved inoculants containing single strains of rhizobia compatible with a defined list of legumes.