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

2015

Research organisatons
Funding source

Trial details

Aims

The majority of farms in low rainfall areas use sheep to provide enterprise diversity, however grazing also offers a range of other system benefits that are generally not accounted for in mixed farming enterprises. Studies have shown that grazing offers a useful tool for managing weeds and pests, improving crop nutrition and yields and providing an option to mitigate risk in pasture crop rotations. In these systems there is a perception of declining performance of the pasture ley, as a result of increasing cropping intensity. As a result, there has been work to show the benefits of increasing crop and pasture inputs, as opposed to district practice crop seeding and fertiliser rates and pasture regeneration from residual seed banks.

A long-term study was established at the Minnipa Agricultural Centre from 2008 to 2015 (EPFS Summaries 2008 to 2014) to assess the impact of grazing on crop and pasture production and soil health and also to evaluate this from a systems perspective.

The eight year demonstration with a wheat, wheat, pasture (volunteer and sown annual medic), wheat, pasture (self-regenerating annual medic), wheat and wheat rotation was also established to determine whether productivity could be improved under a higher input system compared to a lower input and more traditional system and what affect this had on soil fertility.

Key messages
  • Grazing sheep have not damaged soil health over eight years of several crop/pasture rotations.
  • In 2015 total annual biomass was greater in higher input and grazed rotations. High input grazed systems carried twice the stocking rate of a low input system.
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 Mark Klante and Brett McEvoy for site management and John Kelsh for data collection. The Eyre Peninsula Grain and Graze 3 project is funded by GRDC (SFS00028).


Other trial partners 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 2015

Sow date Not specified
Harvest date Not specified
Plot size 350m x 100m
Plot replication 1
Paddock history 2014: Wheat 2013: Wheat 2012: Medic pasture
Fertiliser <p>In 2015 the trial was retained as a self-regenerating annual medic, with a fertiliser treatment of 18:20:00 DAP broadcast @ 100 kg/ha to the high input areas on 23 April.</p>
Herbicide <p>Grass weeds were sprayed-out of the ungrazed sections on 7 October. No spraying was required on grazed treatments.</p>
Download the trial report to view additional method/treatment information

Trial results Table 1

# Treatment 1
Biomass at anthesis (t DM/ha) Water use efficiency (% of potential) Total biomass (t DM/ha)
1 Low input - grazed 2.8 66 5.2
2 Low input - ungrazed 3.7 65 3.7
3 High input - grazed 3.2 65 5.7
4 High input - ungrazed 4.1 54 4.1

Biomass at anthesis t DM/ha


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Total biomass t DM/ha


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Water use efficiency % of potential


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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 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

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.

Trial report and links

2015 trial report