Dryland legume pasture systems: improving nitrogen fixation

2018

Research organisatons
Funding sources

Trial details

Researcher(s) Fiona Tomney (SARDI)
Year(s) 2018
Contributor SARDI Minnipa Agricultural Centre
Trial location(s) Site 14, Minnipa Agricultural Centre, SA
Related trials
Dryland legume pasture systems: improving nitrogen fixation locations
Aims

Legume pastures have been pivotal to sustainable agricultural development in southern Australia. They provide highly nutritious feed for livestock, act as a disease break for many cereal root pathogens, and improve soil fertility through nitrogen (N) fixation. Despite these benefits, pasture renovation rates remain low and there are opportunities to improve the pasture base on many low to medium rainfall mixed farms across southern Australia. There are also reports of poor protein levels in wheat following medic pastures and many reports of poor medic nodulation. Previous work has shown that substantial responses to inoculation are possible in the Victorian Mallee, which is possibly linked to the poor N fixation capacity of some populations of soil rhizobia. The extent to which inoculation can still improve medic nodulation on Eyre Peninsula requires clarification.

The Dryland Legume Pasture Systems (DLPS) project aims to develop recently discovered pasture legumes together with innovative management techniques that benefit animal and crop production and promote their adoption on mixed farms in the low and medium rainfall areas of WA, SA, Vic and southern NSW.  One objective within this work program is to increase the amount of fixed N provided by the pasture.

 

This is a component of a new five year Rural Research and Development for Profit funded project supported by GRDC, MLA and AWI; and involving Murdoch University, CSIRO, SARDI, Department of Primary Industries and Regional Development; Charles Sturt University and grower groups.

Key messages
  • This trial aims to investigate opportunities for symbiotic improvement.
  • Inoculation will be critical to the establishment of new legume species, where they have not previously been grown. The extent to which inoculation can still improve medic nodulation is being investigated.
  • There was no response to medic inoculation in the 2018 trial, even when the inoculation rate was doubled.
  • Trigonella was better nodulated and produced greater root weights than the medics.
  • These results cannot be fully interpreted until the N-fixation data becomes available.
  • Medic breeding lines with improved N-fixation capacity are being developed as part of the Dryland Legume Pasture Systems project and will be tested in 2019.
Lead research organisation South Australian Research and Development Institute
Host research organisation SARDI Minnipa Agricultural Centre
Trial funding source GRDC RnD4Profit-16-03-010
Trial funding source AWI RnD4Profit-16-03-010
Trial funding source MLA RnD4Profit-16-03-010
Trial funding source AGRR&D RnD4Profit-16-03-010
Related program Dryland Legume Pasture Systems (Rural R&D for Profit)
Acknowledgments

This project is supported by funding from the Australian Government Department of Agriculture and Water Resources 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, and Charles Sturt University, as well as 10 grower groups.

Project code: RnD4Profit-16-03-010


Other trial partners Murdoch University, the Commonwealth Scientific and Industrial Research Organisation, the WA Department of Primary Industries and Regional Development, and Charles Sturt University
Download the trial report to view additional trial information

Method

Crop type Mixed species
Treatment type(s)
  • Crop: Type
  • Inoculant: Rate
  • Variety: Type
Trial type Experimental
Trial design Replicated

Minnipa Agricultural Centre 2018

Sow rate or Target density 10 kg/ha
Sowing machinery

The trial at Minnipa in paddock S8 was arranged in a fully randomized block design, with four replications. A similar trial has also been established at Lameroo, SA.

The experiment comprised three inoculation treatments (no rhizobia applied or, standard and high rates of inoculation) and four legumes. The legume species were Herald strand medic, representing an ‘old’ medic; PM250 strand medic, representing a ‘new’ medic; Z2447 medic, a medic with putative improvements in N-fixation capacity; and trigonella, a new legume that is also nodulated by medic rhizobia. The high rate of inoculation was applied as a double rate of recommended label rates of peat inoculant on seed and supplemented with inoculated glass micro-beads also inoculated at double rate and sown at 10 kg/ha with the seed.

Prior to sowing, plots were sampled at 0-10&

Sow date 27 June 2018
Harvest date Not specified
Plot size 5m x 1.5m
Plot replication 4
Plot blocking fully randomised block design
Plot randomisation fully randomised block design
Herbicide

The trial site was sprayed before sowing with 1.5 L/ha Weedmaster (Glyphosate) + 80 ml/ha Nail and 300 ml/100 L of LI 700, to kill any naturalized medic plants that had germinated.

Insecticide

The trial suffered two pest attacks. Firstly by Cowpea aphids which appeared on all lines but at higher density on the vetches, and then by Native Budworm. Fortunately both of these pests were brought under control and did not appear to have caused any lasting damage.

Inoculant The experiment comprised three inoculation treatments (no rhizobia applied or, standard and high rates of inoculation)
Download the trial report to view additional method/treatment information

Download results

Trial results Table 1

# Variety
Treatment 1
Plant density (plants/m2) Rhizobia (Number/seed)
1 Trigonella balansae No rhizobia 37 0
2 Trigonella medium Standard 49 11000
3 Trigonella high High* 47 22000
4 Z2447 nil No rhizobia 66 0
5 Z2447 medium Standard 83 15500
6 Z2447 high High 75 33500
7 PM250 nil Nil 90 0
8 PM250 medium Standard 103 12200
9 PM250 high High 79 29000
10 Herald nil Nil 75 0
11 Herald medium Standard 80 16750
12 Herald high High 116 33500

Plant density plants/m2


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Rhizobia Number/seed


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Observed trial site soil information
Trial site soil testing
Site Depth Type pH EC P K N A OC CAT
Site 14, Minnipa Agricultural Centre, SA 0 - 10cm 8.40
Soil conditions
Trial site Soil texture
Site 14, Minnipa Agricultural Centre, SA Red sandy loam
Derived trial site soil information
Australian Soil Classification Source
Trial site Soil order
Site 14, Minnipa Agricultural Centre, SA Anthroposol
National soil grid Source
NOTE: National Soil Grid data is aggregated information for background information on the wider area
Actual soil values can vary significantly in a small area and the trial soil tests are the most relevant data where available

Soil properties

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Climate

Site 14, Minnipa Agricultural Centre SA 2018


Observed climate information

Rainfall avg ann (mm) 325mm
Rainfall avg gsr (mm) 242mm
Rainfall trial total (mm) 269mm
Rainfall trial gsr (mm) 208mm

Derived climate information

Site 14, Minnipa Agricultural Centre SA

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Some data on this site is sourced from the Bureau of Meteorology

SILO weather estimates sourced from https://www.longpaddock.qld.gov.au/silo/
Jeffrey, S.J., Carter, J.O., Moodie, K.B. and Beswick, A.R. (2001). Using spatial interpolation to construct a comprehensive archive of Australian climate data , Environmental Modelling and Software, Vol 16/4, pp 309-330. DOI: 10.1016/S1364-8152(01)00008-1.

Trial report and links

2018 trial report




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Trial last modified: 13-12-2019 14:22pm AEST