Optimising legume inoculation for dry sowing (S716)

September 11, 2017 Tags Environment, Faba beans, Lower Eyre Peninsula, Soil health

Glasshouse studies in 2016 focused on the survival of different rhizobium products using different soil moistures and temperatures simulating dry sowing conditions. Field trials in 2017 and 2018 will be at three sites (Eyre Peninsula, Mid North and the Mallee). Treatments for field trials include different rhizobium products and placement of the inoculant at seeding.

Interim results are below.

Start:

July 1, 2016

Finish:

July 30, 2019

Project participants

SARDI: Liz Farquharson.

The problem

Comparing the effectiveness inoculation formulations for nodulating faba beans and fixing nitrogen when dry sown.

The research

Two field trials at Wanilla on Lower Eyre Peninsula are assessing optimising incoluation and acid tolerant rhizobia.

More information

Liz Farquharson
SARDI
08 8303 9452
[email protected]

Research aims

The two Eyre Peninsula trials are being conducted at Wanilla on a site with a pHCaCl2 of 4.3 in the top 10cm of soil.

Optimising Inoculation for dry sown beans

The first trial is comparing a range of inoculant formulations for their effectiveness in nodulating faba bean and fixing nitrogen when dry sown. This trial was sown on the 28th of April and was in the ground dry for four weeks before rain.

Acid Tolerant Rhiozbia Trial

This Trial aimed to (i) determine if increasing the rate of peat applied rhizobia inoculant on seed improves nodulation of faba bean when sown dry and (ii) to compare the suitability of two new Gr E-F rhizobia strains with putative acid tolerance to dry sowing.

In the field

The two Eyre Peninsula trials are being conducted at Wanilla on a site with a pHCaCl2 of 4.3 in the top 10cm of soil.

Optimising Inoculation for dry sown beans

This trial was sown on the 28th of April and was in the ground dry for four weeks before rain.

Under these conditions the Novozymes granular product and BASFpeat on seed combined with BASF granule treatments have nodulated beans most effectively and are well ahead in biomass production.
Under these harsh sowing conditions it has been the products with the highest number of rhizobia and most conducive formulation for survival the have worked the best.
Under moist sowing conditions we would expect peat on seed products to perform as well as granules.
A similar trial being conducted on lupin in the mid-north has shown that lupin dry sown and in the ground for 7 days before rain peat on seed out-perfomed the granule option at that site. Biomass, nitrogen fixation and yield will be assessed later in the season.

Acid tolerant rhizobia trial

This trial had ten treatments, one uninoculated (nil) control, the commercial Gr F rhizobia strain WSM1455, and two strains with putative acid tolerance (SRDI954 and SRDI969). All strains were grown up in sterile peats at SARDI and applied at one of three rates to seed (0.5, 1.0 or 2.0 times the recommended rate (RR)) within 24 hours of sowing. This trial was sown at TOS1 on the 28^th of April. The trial was in the ground for four weeks before rain.

The Nil treatments had no nodules confirming this is an inoculation responsive site.
The two new strains nodulated beans at all rates of application.
The commercial strain only nodulated plants when applied at 2x RR.
Biomass, nitrogen fixation and yield will be assessed later in the season.

When will a new strain be available?

Further trials and a range of other duty of care and manufacturing tests are required before these strains will be available commercially. With further funding and all going well we would expect an acid tolerant strain to be available in 2020.

What can growers do now to improve nodulation of bean , pea or lentil on acid soils?

Lime soils to at least pHCaCl2 5.0 to improve the conditions for both nodulation and general growth and nutrition of the crop.
Apply peat inoculant at 2x the recommend rate under optimal conditions or use Novozymes granular products which delivers a high number of rhizobia per gram.

More information will be updated as it becomes available.

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