Variable rate nitrogen


Research organisaton
Funding source

Trial details

Researcher(s) Nicole Dimos (SPAA), Peter Trelor (Precision Ag Services) and Louise McIntish (YPASG)
Year(s) 2011
Contributor Society of Precision Agriculture Australia
Trial location(s) Site 1, Urania, SA
Variable rate nitrogen locations
  • To compare Variable Rate Nitrogen against Flat rate applications.
  • To compare two methods of zoning – using EM38 soil survey and 2009 yield data.
Key messages

Because there was no effect of fertiliser on the yield it meant any potential benefit from VR was greatly reduced. This can likely be put down to the high levels of soil N recorded at the start of 2011. The trial does suggest that this paddock was over fertilised as there was no significant loss of yield from a 40kg/ha reduction in urea in either trial.

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

This project was funded by the Grains Research and Development Corporation (GRD) and run n conjunction with YP Alkaline Soils Group.

Other trial partners Peter Trelor (Precision Ag Services, Minlaton), Louise McIntish (YPASG)
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Crop type Wheat
Treatment type(s)
  • Fertiliser: Rate
  • Soil: Type
Trial type Precision agriculture
Trial design Not applicable

Urania 2011

Sow date 30 May 2011
Harvest date Not specified
Plot size Not specified
Plot replication Not specified

VR Urea on July 2011

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Download results

Trial results Table 1

# Treatment 1
Grain yield (t/ha)
1 VR based on EM38: 60kg/ha urea 5.18
2 VR based on EM38: 100kg/ha urea 5.03
3 VR based on EM38: 140kg/ha urea 4.76
4 Control - flat rate @ 100kg/ha urea 5.22
5 Control - flat rate @ 100kg/ha urea 5.06
6 Control - flat rate @ 100kg/ha urea 4.78
7 VR based on 2009 Yield: 140kg/ha urea 5.26
8 VR based on 2009 Yield: 100kg/ha urea 5
9 VR based on 2009 Yield: 60kg/ha urea 4.68
10 Control - flat rate @ 100kg/ha urea 5.33
11 Control - flat rate @ 100kg/ha urea 5.03
12 Control - flat rate @ 100kg/ha urea 4.73

Grain yield t/ha

Observed trial site soil information
Trial site soil testing
Not specified
Soil conditions
Trial site Soil texture
Site 1, Urania, SA Not specified
Derived trial site soil information
Australian Soil Classification Source
Trial site Soil order
Site 1, Urania, SA Sodosol
National soil grid Source
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.

Site 1, Urania SA

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.

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Trial last modified: 30-09-2019 16:10pm AEST