Building soil carbon in the Murray

As 2023 commences, our four-year ‘building soil carbon in the mid-Murray region’ project draws to a close.

The project was based on the proposition that the best way to build soil organic carbon in irrigated agricultural soils is to grow productive, annual legume pastures. Well managed legume pastures provide not only carbon, but also nitrogen, phosphorus, and sulphur; all of which are required to build soil carbon.

Irrigated pasture production in the Murray region traditionally relied on subclover as the legume component. A series of local demonstrations were established to determine if subclover was still the best pasture legume for this environment or if other cultivars, such as Persian, Balansa or Arrowleaf clover, would be more suited.

Soil carbon project key findings

The four-year demonstrations, on both red and grey soils, have demonstrated that subclover is still a good fit for irrigated (and intermittently irrigated) annual pastures.

Sub clovers:

  • persisted well across different seasons and irrigation intensities
  • were highly productive
  • had a broader herbicide tolerance
  • competed well with broadleaf weeds.

Some other legume species, however, have characteristics that make them suitable for specific purposes, such as Arrowleaf clover for spring production, particularly as hay variety.

Or Balansa clover for persistence and its ability to spread across the paddock.

SARDI Persian, though only sown at one location, also did well at the intensively managed site on red loam soil.

At each site, soil carbon was measured. We found that mostly, where productive pastures grew the soil carbon increased over the four years. There were a couple of unexplained exceptions, but the general trend was positive.

For more information about the results you can check out the findings from the Building Soil Carbon project, watch the video below or contact Kimberley Beer at Local Land Services on 0439 531 306.

Where to next?

We’re currently developing phase two of the project and we’re looking for input on a pasture, grazing or soil amelioration demonstration you'd like see in Murray region.

Is there something you’d like to see established or evaluated?

We’d love to hear your feedback! Share your thoughts through the survey below or call Kimberley (0439 531 306).

We’d like to thank the landholders in the current project who’ve hosted demonstration sites and taken time to contribute to our wrap up video.

This project is supported by Murray Local Land Services, through funding from the Australian Governments National Landcare Program.

Building soil carbon - demonstration site may 2021

Figure 1 Pasture demonstration site, Logie Brae, May 2021

Building soil carbon - demonstration site sep 2021

Figure 2 Pasture demonstration site, Logie Brae, September 2021

Building soil carbon - soil cores

Figure 3 Soil cores at Logie Brae. Red loam, clay soils.

Building soil carbon - demonstration site - slashing

Figure 4 Slashing Noorong site to simulate grazing in absence of sheep, June 2022

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