Demonstration of French Serradella on soils in the Mallee

Background

Local research projects have found that French Serradella has the potential to provide a fodder option on Mallee sandy soils where lupins are normally grown. The potential benefits that serradella in the Mallee include:
• Adaptation to deep infertile, coarse textured soils
• Deep rooting and produces an extended green feed period compared to most annual legumes
• Potential for seed collection and cleaning with on-farm equipment
• Tolerance to pH (4.0< pHCa <7.5)
• Good tolerance to redlegged earth mite and aphids
• Very palatable to stock and high nutritive value
• No major anti-nutritional properties

There is also potential for Serradella to be established using novel methods aimed at reducing the cost of pasture establishment and improving productivity from greater water use efficiency. The methods are:
• Twin sowing where hard seed/pod is sown with the crop before the pasture phase. Little or no pasture is expected to establish in the crop phase. Hard seed “softens” over the summer period and germinates to produce a viable pasture in the following autumn.
• Summer sowing is where hard seed/pod is sown in the summer prior to the pasture phase where the hard seed “softens” and germinate to produce a viable pasture in autumn.

Demonstration Sites

A one hectare French Serradella demonstrations site was dry sown on the 1st of March at Ouyen. This site was was sown to lupin in 2019 and cereal in 2020. Treatment strips were 100 m long and ran from the near peak of an east west sand dune to the neighbouring flat. The site was intersected into 3 zones described as hill, mid-slope and flat. A block of Volga vetch was sown alongside to provide a comparative assessment of current local practice. The 0-10 cm soil pH (CaCl2) was less than 7 only on the hill location at Ouyen, increasing to more than 8 on the flat.

There was no measurable rain from seeding in March until late May. Rainfall was approximately 100 mm for the period from the end of May through to the end of September. A further 60 mm in October/November resulted in a total GSR of near 160 mm at both sites.

Serradella produced an extra 1 to 1.5 tonne biomass than vetch on the hill while vetch produced an extra 1 to 1.5 tonne of biomass to serradella on the midslope and flat (Figure 1).

Figure 1 Total serradella and vetch biomass (tDM/ha) in the 3 soil zones, at 3 sampling times at Ouyen.

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Recommendations

The demonstration sites show that serradella could provide a dual purpose (hay, grain, grazing) alternative to vetch on neutral to acidic deep sandy Mallee soils. These soil types are where lupins are commonly grown. Serradella can also provide operational benefits over vetch such as summer sowing and lower seeding rates.

To successfully establish a French serradella phase pasture we recommend:

  • Sowing in February early March. The time of seeding is necessary to continue the rate of seed softening of the shallow sown seedpods.
  • Sowing on-farm produced seedpod at 5 to 20 kg/ha. The seeding rate is based on the small seedpod size (10 kg/ha = ~250 seedpods/m2).  A soft seeded cultivar such as Eliza requires sowing at 5 kg/ha while 20 kg/ha is required for a hard-seeded cultivar such as Margurita pod.
  • Serradella and lupin share the same rhizobia species for inoculation(Group G/S rhizobia).  A history of lupin in the paddock reduces the the risk of inadequate nodulation and the need for inoculation, particularly where summer sowing of pod is used to establish the pasture.
  • Chemical weed control options include post-seeding pre-emergent Spinnaker (not Simazine) and/or post-emergent Broadstrike and grass selective herbicides plus a spring insecticide for Heliothis control.

Acknowledgements

This virtual field day has been developed as part of the Mallee Sustainable Farming (MSF) project:
“Facilitating enhanced knowledge sharing of Mallee sustainable farming practices”
This project is supported by the Mallee Catchment Management Authority with funding from the Australian Government.

This project was supported by funding from the Australian Government Department of Agriculture, Water & Environment as part of its Rural R&D for Profit program, the Grains Research and Development Corporation, Meat and Livestock Australia and Australian Wool Innovation. The research partners include the South Australian Research and Development Institute, Murdoch University, the Commonwealth Scientific and Industrial Research Organisation, the WA Department of Primary Industries and Regional Development, the NSW Department of Primary Industries and Charles Sturt University, as well as grower groups.