Should the gravel content of soils impact on your input management decisions?

CC BY 4.0

Research organisaton
Funding source

Trial details

Researcher(s) Bill Bowden (West Midlands Group)
Year(s) 2013
Contributor West Midlands Group
Trial location(s) Badgingarra, WA
Should the gravel content of soils impact on your input management decisions? locations

To determine whether adjustments need to be made to a range of decision support systems (DSSs) to quantitatively account for the effect of gravel on inputs such as fertilisers, lime, pesticides and herbicides.

Key messages

The gravel content of a soil certainly affects soil physics and chemistry as well as crop growth processes.

In terms of nutrient management, currently increased gv% is assumed to reduce the amount of nutrients available to the crops, but not to concentrating the effect of fertiliser inputs. Adjustments for gv% are made in systems which use soil test calibration curves to produce recommendations when in fact those adjustments are probably not justified. All of the adjustments which are made, lead to higher fertiliser recommendations.  Even so, no attempt is made to better sample for or estimate gv%.

Whether it is worth investing further resources to confirm or refute the importance of the questions raised in this study is open to question. The complexity of the effects of gv% in real farming systems is such that there may well be no way to improve the predictive power of the models (both regression and mechanistic) to any great extent.

If resources are found to fund future work then it would be best to start with direct measures of whether gravel is inert or not – particularly with respect to water.  Experimental work used in parallel with ROOTMAP model runs to study the effect of gravel on nutrient uptake could also be worthwhile.

Lead research organisation West Midlands Group
Host research organisation West Midlands Group
Trial funding source COGGO
Related program N/A

Thanks to COGGO for funding the work, the West Midlands Group for backing it, to Geoff Anderson for help with access to the BFDC data base and to the many people who replied to the survey with (often) useful comments and suggestions.

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


Crop type Wheat
Treatment type(s)
  • Soil amelioration
Trial type Article/commentary
Trial design Not applicable

Badgingarra 2013

Sow date Not specified
Harvest date Not specified
Plot size Not specified
Plot replication 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
2013 251.5mm
2012 236.0mm
2011 224.8mm
2010 209.6mm
2009 228.5mm
2008 246.8mm
2007 198.9mm
2006 196.0mm
2005 242.6mm
2004 204.2mm
2003 230.9mm
2002 212.7mm
2001 192.5mm
2000 206.7mm
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



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

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

Some data on this site is sourced from the Bureau of Meteorology

SILO weather estimates sourced from
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 last modified: 23-07-2019 10:40am AEST