Comparing offset discs and rotary spading for incorporation of clay on non-wetting soils

2009 - 2010
CC BY 4.0

Research organisatons
Funding source

Trial details

Researcher(s) Stephen Davies (DAFWA)
Year(s) 2009 - 2010
Contributor West Midlands Group
Trial location(s) Badgingarra, WA
Comparing offset discs and rotary spading for incorporation of clay on non-wetting soils locations
Aims

To determine whether crop establishment and grain yield gains from claying can be further improved by matching the clay rich subsoil application rate with the incorporation method.

Key messages
  • Incorporation of the lower subsoil application rates (50 and 100 t/ha) with offset discs resulted in increased canola plant establishment compared with the offset disc control plots without subsoil. However, at the higher subsoil application rates (360 and 450 t/ha) establishment was reduced due to inadequate clay incorporation (Fig. 1). Visually it was clear that the high rates of subsoil application resulted in surface sealing due to the poor incorporation by offset discs and this sealing was sufficient to reduce canola establishment. Incorporation of 50t subsoil/ha using a spader appears to have resulted in a reduction in canola establishment (Fig. 1) but there is no apparent reason why this should the case. Apart from this anomaly there is a trend towards improved plant establishment when higher rates of applied subsoil are spaded (Fig. 1).
  • Comparing grain yields between subsoil incorporation using offset disc and rotary spader is not valid on this trial as the offset disc treatments are situated on pale deep sand which has less water holding capacity and lower potential than the sandy gravel on which the spaded treatments are situated. Canola grain yields in 2010 showed trends not dissimilar to those obtained for wheat on this trial in 2009. For the offset disc treatment there was no impact of the lower subsoil application rates on yield but a trend towards lower yields at the high application rates (Fig. 1) again most likely due to inadequate subsoil incorporation. For the rotary spader there was a trend towards higher yields as the subsoil application rate increased (Fig. 1), indicative of the capacity for the spader to achieve good subsoil incorporation. Overall canola yields were increased by more than 300 kg/ha when either 360 or 450 t/ha spread subsoil was incorporated using a spader (Fig. 1).
  •  In both the 2009 and 2010 seasons the trends in crop establishment and grain yield have demonstrated the principle that when claying the subsoil application rate needs to be ‘matched’ to incorporation method that will be used to incorporate the clay. The results suggest that offset discs are only likely to be successful at incorporating lower subsoil application rates, probably of the order of 150 t/ha or less while rotary spaders are more appropriate for incorporating higher subsoil application rates of 250 t/ha or more.
Lead research organisation Department of Agriculture and Food WA
Host research organisation West Midlands Group
Trial funding source GRDC DAW00204
Related program N/A
Acknowledgments

West Midlands Group would like to thank Andrew Kenny for seeding and managing the 2010 canola crop. Dr Stephen Davies and Breanne Best (DAFWA) for technical support and the WMG growers who established the site.


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

Method

Crop type Oilseed: Canola
Treatment type(s)
  • Soil Improvement: Application Method
Trial type
Trial design

Badgingarra 2009

Sow date Not specified
Harvest date Not specified
Plot size Not specified
Plot replication Not specified
Psuedoreplication Not specified

Badgingarra 2010

Sow date Not specified
Harvest date Not specified
Plot size Not specified
Plot replication Not specified
Psuedoreplication Not specified
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
Badgingarra, WA Not specified
Derived trial site soil information
Australian Soil Classification Source: ASRIS
Trial site Soil order
Badgingarra, WA Chromosol
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 Badgingarra WA
2010 147.5mm
2009 176.1mm
2008 192.9mm
2007 135.2mm
2006 142.1mm
2005 169.7mm
2004 128.0mm
2003 144.9mm
2002 140.2mm
2001 128.6mm
2000 161.9mm
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

Derived climate information

No observed climate data available for this trial.
Derived climate data is determined from trial site location and national weather sources.

Badgingarra WA

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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

2010 trial report



Trial last modified: 06-08-2019 07:54am AEST