Preliminary assessment of grain legume nodulation in the South Australian Mallee

Maarten Ryder1, Matt Denton1 and Ross Ballard2
1University of Adelaide; 2SARDI, Waite Campus, Urrbrae
Peer review: Dr David Herridge, University of New England

Key Messages
• Growers are encouraged to take root samples of legume crops in late winter or early spring to assess nodulation. A nodulation assessment guide that includes photos of plants with poor and good nodulation is available online.
• Nodulation of the inoculated legume crops sampled was generally very good: 6 of 9 sets of root samples were rated good to excellent.
• Nodulation was poor where there was metribuzin damage to peas. This adds to observations previously made by other growers in the region about metribuzin damage on sandier soils.
• Poor nodulation of one crop of lupins remains unexplained. Tests are under way to find out whether the use of saline bore water to prepare inoculant was the cause. Clean potable water is recommended for mixing inoculant.
• Serious Rhizoctonia damage was seen on some lupin and pea crops.