Variable rate nitrogen

CC BY 4.0

Research organisaton
Funding source

Trial details

Researcher(s) Nicole Dimos (SPAA)
Felicity Turner (Vision Ag)
Grant Yates (Vision Ag)
Year(s) 2011
Contributor Society of Precision Agriculture Australia
Trial location(s) Tintinara, SA
Variable rate nitrogen locations

To compare the effects of variable rate nitrogen applications on wheat yield across diverse soil types.

Key messages

There was no response shown to varying nitrogen rates across the 4 yield zones on this paddock. This could be due to the adequate levels of nitrogen present before seeding as show in the 0-10 and 10-60cm soil test results and also reinforced with the NDVI esults, this would stem from good fertiliser history and rotation from the Harkness’s.This could give confidence that rates could be reduced on the lower yielding areas without risk of impacting on yield and consequently increasing gross margins across the paddock by saving wasted inputs on poorer performing soil types and leaving rates higher on better performing areas to maximise returns when seasons are more favourable.

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 (GRDC)

Other trial partners Harkness family (Property owners)
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

Tintinara 2011

Sow rate or Target density 92 kg/ha
Sow date 7 June 2011 7 June 2011
Harvest date Not specified
Plot size Not specified
Plot replication Not specified

DAP 80kg/ha 7 June 2011.  Urea @ 20, 60 and 100kg/ha 10 August 2011

Download the trial report to view additional method/treatment information

Download results

Trial results Table 1

# Treatment 1
Treatment 2
Grain yield (t/ha)
1 Low yield zone (sand) Low N @ 20kg/ha 2.68
2 Low yield zone (gravel) Low N @ 20kg/ha 2.81
3 Medium yield zone Low N @ 20kg/ha 3.51
4 High yield zone Low N @ 20kg/ha 4.04
5 Low yield zone (sand) Medium N @ 60 kg/ha 2.56
6 Low yield zone (gravel) Medium N @ 60 kg/ha 2.71
7 Medium yield zone Medium N @ 60 kg/ha 3.6
8 High yield zone Medium N @ 60 kg/ha 4.04
9 Low yield zone (sand) High N @ 100 kg/ha 2.61
10 Low yield zone (gravel) High N @ 100 kg/ha 2.82
11 Medium yield zone High N @ 100 kg/ha 3.58
12 High yield zone High N @ 100 kg/ha 4.03

Grain yield t/ha

Observed trial site soil information
Trial site soil testing
Not specified
Soil conditions
Trial site Soil texture
Tintinara, SA Gravelly sand
Derived trial site soil information
Australian Soil Classification Source: ASRIS
Trial site Soil order
Tintinara, SA Sodosol
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 Tintinara SA
2011 308.1mm
2010 294.7mm
2009 240.9mm
2008 204.1mm
2007 201.1mm
2006 230.5mm
2005 257.2mm
2004 260.7mm
2003 258.6mm
2002 239.9mm
2001 271.2mm
2000 275.6mm
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.

Tintinara 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.

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