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

2016

Research organisatons
Funding source

Trial details

Researcher(s) Brian Dzoma (SARDI)
Year(s) 2016
Contributor SARDI Minnipa Agricultural Centre
Trial location(s) Piednippie, SA
Improving medic pastures in low rainfall mixed farming systems - how to get the most ‘free’ N locations
Aims

To investigate the impact of grazing, soil nutrition and rhizobial inoculants on dry matter production, nodulation and N2-fixation of a regenerating medic pasture under field conditions.

Key messages
  • The paddock contained a population of effective rhizobia and so the number of nodules on lateral and taproots was not affected by the addition of different rhizobial inoculants.
  • Improved soil nutrition did not affect dry matter production and nodulation.
  • Grazing (simulated) reduced the total dry matter produced by the medic pasture, however the use of sheep would provide a more realistic assessment of grazing on DM production, nodulation and N2-fixation.
Lead research organisation Southern Farming Systems
Host research organisation SARDI Minnipa Agricultural Centre
Trial funding source GRDC SFS00028
Related program Grain & Graze 3
Acknowledgments

Thanks to Brent Cronin and family for allowing us to have the trial on his property, Ian Richter for technical support, Ross Ballard and Nigel Wilhelm for their continued input in this project. The Eyre Peninsula Grain and Graze 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

Piednippie 2016

Sowing machinery

A replicated field trial was established on 7 April 2016 on a regenerating barrel medic pasture (var. parabinga) at Piednippie on a grey sandy soil with 1.5% organic carbon, 24 mg/kg Colwell P and 20 kg N/ha in the 0-10 cm root zone. Before sowing, the soil contained 823 medic rhizobia per gram (0-10 cm) and they were 76% as effective as the commercial inoculant (WSM 1115) in combination with Parabinga. All treatments (Table 1) were imposed on 24 May, which was followed by 26 mm of rain over three days. ALOSCA rhizobia granules (containing approx. 23,000 rhizobia/g) were spread over the plots by hand. Peat inoculant was dissolved in water overnight and sprayed onto plots using a backpack sprayer at 250 L/ha of water. Parabinga seed was spread by hand (over the treatments with added seed) and raked in to simulate prickle-chaining in order to improve seed-soil contact and the inoculated Parabinga seed had 26,000 rhizobia/seed. The trial site was sprayed with

Sow date 7 April 2016
Harvest date Not specified
Plot size 3m x 1.5m
Plot replication 3
Plot randomisation Yes
Fertiliser

Table 1 Treatment details

Treatments

Formulation/application

Application rate/ha

Peat

Dissolved

250 g/250 L water

 
Inoculant See sowing method
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Trial source data and summary not available
Check the trial report PDF for trial results.
Observed trial site soil information
Trial site soil testing
Site Depth Type pH EC P K N A OC CAT
Piednippie, SA 0 - 10cm 24.00 20.00 1.50
Soil conditions
Trial site Soil texture
Piednippie, SA Grey calcareous sandy loam
Derived trial site soil information
Australian Soil Classification Source: ASRIS
Trial site Soil order
Piednippie, 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 Piednippie SA
2016 168.5mm
2015 138.7mm
2014 162.0mm
2013 130.5mm
2012 128.2mm
2011 159.1mm
2010 146.5mm
2009 162.3mm
2008 137.7mm
2007 115.4mm
2006 139.5mm
2005 132.4mm
2004 133.5mm
2003 137.1mm
2002 127.4mm
2001 143.0mm
2000 145.7mm
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

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Climate

Piednippie SA 2016


Observed climate information

Rainfall avg ann (mm) 379mm
Rainfall avg gsr (mm) 304mm
Rainfall trial total (mm) 485mm
Rainfall trial gsr (mm) 323mm

Derived climate information

Piednippie SA

NOTE: Exact trial site locality unknown - Climate data may not be accurate
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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

2016 trial report



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