Variable rate phosphorus


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 2, Urania, SA
Variable rate phosphorus locations
  • To compare variable rate phosphorus against flat rate applications.
  • To compare ' P Replacement' with P applications based on EM38 soil surveys.
Key messages

With good soil phosphorus reserves ‘P replacement’ is a safe and viable option that will help farmers manage their inputs and maintain soil fertility in high yielding areas of the paddock.

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 Ashley and Louise Wakefield (Propert owner)
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

Urania 2011

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

Download results

Trial results Table 1

# Treatment 1
Grain yield (t/ha)
1 VR based on P Replacement: 80kg/ha DAP 5.28
2 VR based on P Replacement: 100kg/ha DAP 5.34
3 VR based on P Replacement: 120kg/ha DAP 5.35
4 Control - flat rate @ 100kg/ha DAP 5.26
5 Control - flat rate @ 100kg/ha DAP 5.28
6 Control - flat rate @ 100kg/ha DAP 5.24
7 VR based on EM38: 75kg/ha DAP 5.24
8 VR based on EM38: 100kg/ha DAP 5.3
9 VR based on EM38: 125kg/ha DAP 5.2
10 Control - flat rate @ 100kg/ha DAP 5.33
11 Control - flat rate @ 100kg/ha DAP 5.31
12 Control - flat rate @ 100kg/ha DAP 5.16

Grain yield t/ha

Observed trial site soil information
Trial site soil testing
Not specified
Soil conditions
Trial site Soil texture
Site 2, Urania, SA Not specified
Derived trial site soil information
Australian Soil Classification Source
Trial site Soil order
Site 2, 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 2, 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.

Individual Trial Project data and information and OFT metadata are licensed under a Creative Commons Attribution 4.0 International License.
The data and information accessed through OFT may also be subject to Terms of Use specified by the Trial Contributor,
in which case the Terms of Use of a Trial Contributor take precedence over other information provided on OFT.
Trial last modified: 30-09-2019 16:14pm AEST