Computer modelling helps fallow decision making

CC BY 4.0

Research organisaton
Funding source

Trial details

Researcher(s) Richard MacCallum (NSW Agriculture)
Year(s) 2003
Contributor Central West Farming Systems
Trial location(s) Condobolin, NSW
Computer modelling helps fallow decision making locations

To explain how computer modelling helps fallow decision making.

Key messages
  • Using a locally tested computer model (APSIM) different fallow commencement dates were tested for their effect on soil water and wheat yield.
  • Soil was estimated to contain at least 80 mm of water to a depth of 1.4 m at sowing in 50% of years if a clean fallow out of pasture was commenced on 15th September at Vermont Hill and 15th October at Gunning Gap.
  • Predicted yield was near maximum and drainage in the fallow was minimised in 50% of years by not  commencing the fallow before these dates.
  • Water limited yield potential in 50% of years is 3t/ha at Gunning Gap and 2.6 t/ha at Vermont Hill.
Lead research organisation Central West Farming Systems
Host research organisation N/A
Trial funding source GRDC
Related program N/A

This project was funded by the GRDC through the University of Western Sydney (Hawkesbury). Thanks to Peter Cornish, Neil Fettell and the farmers who participated in this work.

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


Crop type Fallow
Treatment type(s)
  • Soil: Preparation
Trial type Article/commentary
Trial design Unreplicated

Condobolin 2003

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
Condobolin, NSW Not specified
Derived trial site soil information
Australian Soil Classification Source: ASRIS
Trial site Soil order
Condobolin, NSW Kandosol
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 Condobolin NSW
2003 154.0mm
2002 162.4mm
2001 230.3mm
2000 300.5mm
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.

Condobolin NSW


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 report and links

2003 trial report

Trial last modified: 19-03-2019 13:45pm AEST