Improving medic pastures in low rainfall mixed farming systems - how to get the most ‘free’ N

2015

Research organisatons
Funding source

Trial details

Researcher(s) Jessica Crettenden (SARDI)
Year(s) 2015
Contributor SARDI Minnipa Agricultural Centre
Trial location(s) Minnipa Agricultural Centre, SA
Improving medic pastures in low rainfall mixed farming systems - how to get the most ‘free’ N locations
Aims

To look at current techniques used by farmers, or recommended by consultants, to improve medic pastures and determine the most effective method to optimise N2-fixation. Biomass, nodulation and N2-fixation differences between management practices, including inoculation treatments on both sown and regenerating medic stands were measured. The trial also investigated if grazing medic pastures in the break phase of the rotation benefits or impedes nodulation and subsequent N2-fixation.

Key messages
  • The paddock utilised for the trial had a significant number of effective naturalised medic rhizobia. There was no rhizobial inoculation response.
  • Total annual biomass was higher in the regenerating medic plots versus sown treatments due to earlier germination and growth of naturalised medic.
  • Grazing increased overall medic production.
Lead research organisation Southern Farming Systems
Host research organisation SARDI Minnipa Agricultural Centre
Trial funding source GRDC SFS00028
Related program Grain & Graze 3
Acknowledgments

I gratefully acknowledge Jake Howie and Ross Ballard for their guidance throughout the trial and Leigh Davis, Brenton Spriggs, Brett McEvoy and John Kelsh for site establishment and management. The Eyre Peninsula Grain and Graze 3 project is funded by GRDC (SFS00028).


Other trial partners Not specified
Download the trial report to view additional trial information

Method

Crop type Pasture: Medic
Treatment type(s)
  • Crop: Variety
  • Fertiliser: Rate
  • Seed treatment: Inoculant
Trial type Experimental
Trial design Replicated

Minnipa Agricultural Centre 2015

Sowing machinery

The trial was designed to mimic current options used by farmers to manage their regenerating and sown medic pastures, with a focus on treatments adding fertilizer and/or rhizobial inoculant in some form (Table 1). Simulated grazing (mowing) was imposed on half of each plot at opportune periods throughout the season, to imitate the grazing management of medic pastures in a mixed farming system. A site was located in a paddock that had grown wheat for the past two years.

 

Table 1 Number, sowing method, seed type and rate of trial treatments.

No.

Sowing

Sow date 19 May 2015
Harvest date Not specified
Plot size 22m x 24m
Plot replication 3
Plot randomisation Yes
Fertiliser

No.

Sowing method*

Seed type**

Treatment

1

R

Nil

Control

&
Herbicide

Grass weeds were sprayed out of all treatments using 200 ml/ha of Elantra Xtreme and Hasten spray adjuvant @ 500 ml/100 L water on 16 July.

Inoculant See sowing method
Download the trial report to view additional method/treatment information
Trial source data and summary not available
Check the trial report PDF for trial results.
Observed trial site soil information
Trial site soil testing
Not specified
Soil conditions
Trial site Soil texture
Minnipa Agricultural Centre, SA Red sandy loam
Derived trial site soil information
Australian Soil Classification Source: ASRIS
Trial site Soil order
Minnipa Agricultural Centre, SA Calcarosol
Soil Moisture Source: BOM/ANU
Average amount of water stored in the soil profile during the year, estimated by the OzWALD model-data fusion system.
Year Minnipa Agricultural Centre SA
2015 504.4mm
2014 556.5mm
2013 476.4mm
2012 520.3mm
2011 558.1mm
2010 543.4mm
2009 534.2mm
2008 442.9mm
2007 440.4mm
2006 473.1mm
2005 447.8mm
2004 447.2mm
2003 462.9mm
2002 460.3mm
2001 504.3mm
2000 501.8mm
National soil grid Source: CSIRO/TERN
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

Loading

Climate

Minnipa Agricultural Centre SA 2015


Observed climate information

Rainfall avg ann (mm) 325mm
Rainfall avg gsr (mm) 241mm
Rainfall trial total (mm) 333mm
Rainfall trial gsr (mm) 258mm

Derived climate information

Minnipa Agricultural Centre SA

Loading
Loading
Loading

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

2015 trial report



Trial last modified: 08-10-2019 12:11pm AEST