Grain & Graze 3 - The impact of livestock on paddock health

2016

Research organisatons
Funding source

Trial details

Aims

Mixed livestock and cropping systems have an important role to play in the diversification, risk management and sustainability of farming in low rainfall areas. The majority of farms in these areas use livestock to provide enterprise diversity and risk management, however grazing also offers a range of other system benefits that are generally not accounted for in mixed farming enterprises. As a result of increasing cropping intensity in these systems, there is a perception of declining productivity of the pasture phase, with pastures remaining largely unimproved and most farming systems continuing to rely on self-regenerating medic for livestock feed and nitrogen (N).

Pastures in these lower input mixed farming systems are generally set stocked and grazed at low stocking rates throughout the season with minimal effort to manage grazing for optimal production. Farmers are hesitant to increase grazing in the break phase of the rotation partly due to the perception that livestock can damage soil health, remove organic matter and induce weed germination, but also because their efforts are often concentrated on the cropping enterprise due to the income it brings into the business. With prices for livestock (both meat and wool) increasing over the past decade, and the valuable nutrition and disease break effect that the pasture phase provides to subsequent cereal crops, interest in the productivity and profitability of medic and livestock systems has increased.

A long-term study was established at the Minnipa Agricultural Centre from 2008 to 2016 (EPFS Summaries 2008 to 2015) to assess the systems impact of grazing on crop and pasture production, and soil health. The nine-year broad acre demonstration with a wheat-medic rotation (Table 1) also tested whether productivity could be improved under a higher input system (e.g. higher fertiliser and seeding rates, establishment of improved pasture) compared to a lower input and more traditional system (district practice seed and fertiliser inputs, volunteer pasture), and what effect this had on soil fertility.

Key messages
  • Over nine seasons, incorporating livestock into the rotation improved overall system outcomes in this trial, including; increased nitrogen cycling and water use efficiency, reduction in weed and pest populations and no negative effects on cereal performance or soil health, while value adding to stubble and pastures by grazing.
  • The high input grazed farming system had a gross margin of over $100/ha/year more than lower input and ungrazed treatments over the nine-year trial period.
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 the help of Jake Hull, Wade Shepperd and John Kelsh for site management and Ian Richter, Sue Budarick and Brett Hay for data collection. I would also like to thank Barry Mudge with his assistance in the basic economic analysis of the trial. The Eyre Peninsula Grain and Graze 3 project is funded by GRDC (SFS00028).


Other trial partners Participating organisations: EP, BCG, MSF, Ag Excellence Alliance.
Download the trial report to view additional trial information

Method

Crop type
Treatment type(s)
  • Fertiliser: Rate
  • Grazing: Regime
  • Sowing: Rate
Trial type Demonstration
Trial design Unknown

Minnipa Agricultural Centre 2016

Sow date Not specified
Harvest date Not specified
Plot size 100m x 350m
Plot replication 1
Paddock history 2015: Medic pasture 2014: Wheat 2013: Wheat
Fertiliser <table border="1" cellpadding="0" cellspacing="0"> <tbody> <tr> <td> <p>2016</p> </td> <td> <p>Wheat sown @ 50 kg/ha + 40 kg/ha DAP</p> </td> <td> <p>Wheat sown @ 70 kg/ha + 60 kg/ha DAP</p> </td> </tr> </tbody> </table>
Download the trial report to view additional method/treatment information

Trial results Table 1

# Treatment 1
Gross margin high input (grazed) ($/ha) Gross margin low input (grazed) ($/ha) Gross margin high input (ungrazed) ($/ha) Gross margin low input (ungrazed) ($/ha)
1 2008 wheat -42 -49 -42 -49
2 2009 wheat 905 803 879 829
3 2010 medic 284 96 -39 -23
4 2011 wheat 465 362 366 284
5 2012 medic 89 26 -27 -27
6 2013 wheat 464 356 390 332
7 2014 wheat 749 598 677 525
8 2015 medic 151 86 -60 -15
9 2016 wheat 490 372 490 339

Gross margin high input (grazed) $/ha


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Gross margin high input (ungrazed) $/ha


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Gross margin low input (grazed) $/ha


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Gross margin low input (ungrazed) $/ha


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Observed trial site soil information
Trial site soil testing
Not specified
Soil conditions
Trial site Soil texture
Site 17, Minnipa Agricultural Centre, SA Red sandy loam
Derived trial site soil information
Australian Soil Classification Source
Trial site Soil order
Site 17, Minnipa Agricultural Centre, SA Calcarosol
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 17, Minnipa Agricultural Centre SA 2016


Observed climate information

Rainfall avg ann (mm) 325mm
Rainfall avg gsr (mm) 241mm
Rainfall trial total (mm) 391mm
Rainfall trial gsr (mm) 268mm

Derived climate information

Site 17, 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.