Managing wheat yield and quality risks through plant density and nitrogen


Research organisaton
Funding sources

Trial details

Researcher(s) Christine Zaicou-Kunesch, Melaine Kupsch and Anne Smith (DAFWA)
Year(s) 2012
Contributor Liebe Group
Trial location(s) East Dalwallinu, WA
Managing wheat yield and quality risks through plant density and nitrogen locations

The objective of this research is to determine the value of agronomic management (plant density and nitrogen) on production of quality grain for profitable wheat systems. Increasing plant density is a useful tool to increase the competitiveness of a crop against weeds, however, how will this influence grain yield and quality for the new wheat varieties.

Key messages

Increasing plant density is a tool to improve a crop’s competitiveness against weeds. This strategy did not adversely affect the yield of the varieties at the Liebe Main Trial Site in 2012. 

Nitrogen treatments did not significantly influence crop yield however, did influence grain protein. The soil nitrogen levels and season are likely to have influenced this result. Soil testing and understanding the crops requirements as the season unfolds are useful strategies to manage crop performance economically.

The environment is likely to have had the bigger influence on the performance of the varieties than plant density or nitrogen. Growing season rainfall for 2012 was lower than average and disease patches (likely Rhizoctonia) were evident at the trial. The water use efficiency at the site was 13 kg/mm given growing season rainfall (April to October) was 133mm (plus 34mm in January) and grain yields of 1.98 t/ha across whole trial.

Lead research organisation N/A
Host research organisation N/A
Trial funding source GRDC DAW00218
Trial funding source DAFWA
Related program N/A

Appreciate the support of the Liebe Group with trial planning and preparation. DAFWA’s technical services team for terrific trial management. GRDC and DAFWA jointly support this research aiming to improve profitability of wheat production through the Wheat Agronomy Project DAW 218.

Other trial partners Not specified
Download the trial report to view additional trial information


Crop type Wheat
Treatment type(s)
  • Fertiliser: Rate
  • Sowing: Rate
Trial type Experimental
Trial design Randomised,Replicated,Blocked

East Dalwallinu 2012

Sow date 22 May 2012
Harvest date Not specified
Plot size 20m x 1.54m
Plot replication 3
Paddock history 2009 wheat, 2010 wheat, 2011 canola

22/5/12: 100 kg/ha Agstar Extra, 25 kg/ha Muriate of Potash


22/5/12: 100 mL/ha Dominex, 118 g/ha Sakura,

13/7/12: 1 L/ha Hasten, 1 L/ha Decision;

23/7/12: 700 mL/ha Barracuda, 2.5 g/ha Ally


22/5/12: 200 mL/ha Talstar

Download the trial report to view additional method/treatment information

Download results

Trial results Table 1

# Variety
Treatment 1
Treatment 2
Protein (%) Grain yield (t/ha)
1 Cobra 14 kg N/ha 13.5 1.67
2 Cobra 30 kg N/ha 13.7 1.87
3 Cobra 60 kg N/ha 14.7 1.7
4 Cobra 90 kg N/ha 14.8 1.93
5 Cobra 105 plants/m2 1.76
6 Cobra 169 plants/m2 1.68
7 Cobra 210 plants/m2 1.65
8 Cobra 266 plants/m2 1.72
9 Corack 14 kg N/ha 12.4 2.06
10 Corack 30 kg N/ha 13 2.15
11 Corack 60 kg N/ha 13.6 2.2
12 Corack 90 kg N/ha 14.7 2
13 Corack 138 plants/m2 2.18
14 Corack 199 plants/m2 2.15
15 Corack 207 plants/m2 2.07
16 Corack 88 plants/m2 2.09
17 Mace 14 kg N/ha 11.9 2.16
18 Mace 30 kg N/ha 12.7 2.13
19 Mace 60 kg N/ha 13.1 2.06
20 Mace 90 kg N/ha 14.3 1.92
21 Mace 100 plants/m2 2
22 Mace 176 plants/m2 2.05
23 Mace 198 plants/m2 2.1
24 Mace 292 plants/m2 2.16

Grain yield t/ha


Protein %

Observed trial site soil information
Trial site soil testing
Site Depth Type pH EC P K N A OC CAT
East Dalwallinu, WA 0 - 10cm Loamy Clay 5.40 0.09
East Dalwallinu, WA 10 - 30cm Loamy Clay
Soil conditions
Trial site Soil texture
East Dalwallinu, WA Loamy clay
Derived trial site soil information
Australian Soil Classification Source
Trial site Soil order
East Dalwallinu, WA Kandosol
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



East Dalwallinu WA 2012

Observed climate information

Rainfall trial gsr (mm) 133mm

Derived climate information

East Dalwallinu WA


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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