Variable rate nitrogen

CC BY 4.0

Research organisaton
Funding source

Trial details

Researcher(s) Nicole Dimos (SPAA)
Neil McMillan (FSG)
James Mwendwa (CWFS)
Leighton Wilksch (SPAA)
Year(s) 2011
Contributor Society of Precision Agriculture Australia
Trial location(s) Nyngan , NSW
Variable rate nitrogen locations
  • To compare the effects of nitrogen on cereal crop yield and protein levels.
  • To compare the performance of variable rate nitorgen applications to determine profitable future rate applications.
Key messages

In 2010, at Wass brothers’ property in Nyngan, a very wet season caused the normally poor performing areas to perform just as well as the good areas in this paddock regardless of additional nitrogen application. In other paddocks across the farm, there were significant yield differences across each paddock. However, in the previous years Wass’s have always wanted to apply N and have had mixed results possibly because of soil and water variability. Most seasons they have areas that burnout and areas which could use a higher application of N and give a better yield. In 2011, Hayden intended to try to understand what was driving these differences, and yield maps are a way of spatially determining different zones. Therefore, this trial was set up.

Lead research organisation Society of Precision Agriculture Australia
Host research organisation N/A
Trial funding source GRDC SPA000010
Related program N/A

“The Soaks” property owners Dion, Bert Barb Woolford. Paddock and trial sown by Dion Woolford. Tim Moyle Landmark Kimba pegged trials and applied urea. Linden Masters MAC monitored plots and interpreted results. Leigh Davis and Brenton Spriggs SARDI reapt plots. Trials coordinator and FSG contact is Linden Masters

Other trial partners Incitec Pivot (Soil Tests). Wass Brothers PTY LTD Nyngan (Growers).
Download the trial report to view additional trial information


Crop type Wheat
Treatment type(s)
  • Fertiliser: Rate
  • Soil: Type
Trial type Precision agriculture
Trial design Not applicable

Nyngan 2011

Sow rate or Target density 50kg/ha
Sow date 30 May 2011 End of May
Harvest date 3 November 2011 3 November 2011
Plot size 2m x 20m
Plot replication Not specified

Easy N 60L/Ha in 5 x 36m test strips, 250kg Urea/Ha in 2m x 5m plots.

Download the trial report to view additional method/treatment information

Download results

Trial results Table 1

# Treatment 1
Treatment 2
Protein (%) Grain yield (t/ha) Test weight (kg/hL) Screenings (%) Moisture (%) Plant available water (mm)
1 0kg urea Sandy loam 10.4 1.71 66.4 13.1 11.3 18.96
1 Depth 15-30 cm Sandy loam 11.2 1.64 70.2 9.4 11.4 19.2
2 100kg urea Sandy loam 11.5 1.71 68.1 9.2 11.3 13.21
2 Depth 60-90 cm Sandy loam 12.5 1.7 71.6 8.7 11.1 11.64
3 Dpeth 90-120 cm Deep sand 10.1 1.49 59.8 14.1 11.4 19.38
3 50kg urea Deep sand 10.3 1.64 63.4 15 11.5 11.62
4 100kg urea Deep sand 10.6 1.51 68.8 7.6 11.6
4 200kg urea Deep sand 10.9 1.48 73.4 8.6 11.3

Grain yield t/ha


Moisture %


Plant available water mm


Protein %


Screenings %


Test weight kg/hL

Observed trial site soil information
Trial site soil testing
Not specified
Soil conditions
Trial site Soil texture
Nyngan , NSW Red clay loam
Derived trial site soil information
Australian Soil Classification Source: ASRIS
Trial site Soil order
Nyngan , NSW Vertosol
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 Nyngan NSW
2011 541.4mm
2010 567.7mm
2009 518.9mm
2008 489.0mm
2007 403.0mm
2006 402.1mm
2005 430.8mm
2004 408.5mm
2003 411.4mm
2002 431.5mm
2001 489.6mm
2000 508.6mm
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.

Nyngan 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 last modified: 30-09-2019 16:09pm AEST