Jessica Crettenden (SARDI) and Roy Latta (Dodgshun Medlin)
|Contributor||SARDI Minnipa Agricultural Centre|
Site 17, Minnipa Agricultural Centre, SA
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 2014 (EPFS Summaries 2008 to 2013) to assess the impact of grazing on crop and pasture production and soil health and also to evaluate this from a systems perspective.
The seven 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.
|Lead research organisation||
Southern Farming Systems
|Host research organisation||
SARDI Minnipa Agricultural Centre
|Trial funding source||GRDC SFS00028|
Grain & Graze 3
We gratefully acknowledge the help of Mark Klante and Brett McEvoy for site management and Ian Richter and Wade Shepperd for data collection.
|Other trial partners||EP, BCG, MSF, Ag Excellence Alliance|
|Sow rate or Target density||50kg/ha|
|Sow date||10 May 2014|
|Harvest date||31 October 2014|
|Plot size||350m x 100m|
|Paddock history||2013: Wheat2012: Medic pasture2011: Wheat2010: Medic pasture2009: Wheat2008: Wheat|
7 kg N/ha and 8 kg P/ha (45 kg/ha DAP) and 70 kg/ha with 13 kg N/ha and 15 kg P/ha (75 kg/ha DAP) for the low and high input treatments respectively.
Weed control was imposed on all treatments as required in both summer and during the growing season.
||Establishment plants (plants/m2)||pH (value)||Retention (%)||Emergence plants (plants/m2)||Organic carbon (%)||Grain yield (t/ha)||Soil N (mg/kg)|
|1||█ Wheat:Mace||█ Low input - grazed||15.7||8||15.7||1.72 (P=0.05)||1||2.8||78|
|2||█ Wheat:Mace||█ Low input - un-grazed||14.8||8||14.8||1.72 (P=0.05)||0.9||2.7||39|
|3||█ Wheat:Mace||█ High input - grazed||19.4||8||19.4||1.72 (P=0.05)||1.1||3.5||85|
|4||█ Wheat:Mace||█ High input - un-grazed||18.7||8||18.7||1.72 (P=0.05)||1.1||3.4||54|
|Rainfall trial gsr (mm)||290mm|
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.