Can we improve wheat yields?


Research organisaton
Funding source

Trial details

Researcher(s) Nigel Wilhelm (SARDI)
Year(s) 2005
Contributor Agriculture Kangaroo Island Incorporated
Trial location(s) Stokes Bay Road,
Can we improve wheat yields? locations

To identify key ingredients of agronomic packages that deliver high yielding wheat crops with good quality in the Parndana environment.

Key messages
  • Our standard package of 100 kg 18:20/ha at seeding under the seed row (to avoid fertiliser toxicity),  and two top-ups of nitrogen during the season (50 kg N/ha as broadcast urea each time) was not the right combination for wheat at our site last year. It would appear that we were far too generous with our N inputs because we could leave out all fertiliser N and not suffer any yield loss. However, some N would appear to have been necessary to maintain high protein levels.
  • In addition, our standard package of one trial spray in September did not cope with the stripe rust  infection in such a susceptible crop as Wyalkatchem. A Jockey seed dressing helped but another foliar spray of Tilt at flag leaf emergence gave the best control of the options tested.
    • This trial showed that under the high productivity conditions of Kangaroo Island, P fertiliser is still a vital requirement, even if the soil has high P reserves.
    • There was no evidence that extra management options provided any further benefits to wheat performance (ie extra seed dressings, an early aphid spray, B or K fertiliser or use of a growth regulant) under the conditions of last year’s trial.
    • All yields fell far short of the French/Schultz potential yield of 8.4 t/ha (based on the growing season rainfall in 2005 of 532 mm) which suggests that we still have a lot to learn about growing wheat under Kangaroo Island conditions, although the delayed seeding date of 28 June would have contributed to the relatively low yields.
Lead research organisation Agriculture Kangaroo Island Incorporated
Host research organisation N/A
Trial funding source GRDC
Related program N/A
Acknowledgments N/A
Other trial partners SARDI
Download the trial report to view additional trial information


Crop type Cereal (Grain): Wheat
Treatment type(s)
  • Fertiliser: Rate
  • Fertiliser: Timing
  • Fertiliser: Type
  • Fungicide: Type
  • Growth regulator: Type
Trial type Experimental
Trial design Replicated

Stokes Bay Road 2005

Sow date Not specified
Harvest date Not specified
Plot size Not specified
Plot replication Not specified
Psuedoreplication Not specified
Download the trial report to view additional method/treatment information

Download results

Trial results Table 1

# Treatment 1
Plant density (plants/m2) Grain yield (t/ha) Protein (%)
1 Standard 151 3.37 14.3
2 Seeding N 177 3.53 14.3
3 Canopy manag N - 3.44 14
4 Late N - 3.22 144
5 No N 186 3.61 13.5
6 No P 133 2.6 13.3
7 Extra K 169 3.33 14.4
8 Extra B - 3.38 13.6
9 Growth reg - 3.04 14.3
10 Amistar Xtra - 3.4 13.9
11 Fastac - 3.31 14
12 Apron 141 3.45 14
13 Jockey 161 3.83 13.9
14 Gaucho 180 3.5 14.1
15 Everything - 3.73 14.1
16 Tilt at flag - 4.68 13.6

Grain yield t/ha


Plant density plants/m2


Protein %

Observed trial site soil information
Trial site soil testing
Not specified
Soil conditions
Trial site Soil texture
Stokes Bay Road, Not specified
Derived trial site soil information
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 Stokes Bay Road
2005 437.9mm
2004 467.6mm
2003 479.7mm
2002 428.8mm
2001 437.5mm
2000 429.7mm
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.

Stokes Bay Road


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

2005 trial report

Trial last modified: 15-12-2021 10:03am AEST