Nitrogen application at stem elongation, is it worth the investment?


Research organisatons
Funding source

Trial details

Researcher(s) Fabio Arsego (SARDI), Andrew Ware (SARDI)
Year(s) 2018
Contributor SARDI Minnipa Agricultural Centre
Trial location(s) Site 6, Minnipa Agricultural Centre, SA
Related trials
Nitrogen application at stem elongation, is it worth the investment? locations

This research aims to determine whether adding extra nitrogen (N) at GS31 will bring benefits above the current standard practice of only applying nitrogen at or near sowing in three different Eyre Peninsula (EP) environments.


Every season, growers need to make choices over limited resources in order to maximise their profitability. Nitrogen and water represent two of the key limiting resources which set the grain yield potential of a paddock. The unpredictability of growing season rainfall patterns restricts in-season N applications for EP growers, due to the associated high economic risks. Therefore, less than optimum N rates are applied in many instances, and maximum grain yield gains and optimum protein contents are not reached on occasions where opportunities have existed. Understanding soil water and N dynamics can be useful to determine if extra N application at GS31 is worth the investment in EP dryland farming systems.

Key messages
  • At Cummins, an increase of up to 100% grain yield in wheat to 5 t/ha over the control was reached by applying 120 kg N/ha (two split applications of 60 kg/ha each at emergence and before GS31) and extra irrigation (50 mm) at GS31.
  • At Lock, up to a 19% higher grain yield to 5 t/ha was achieved compared to control by adding extra irrigation (50 mm) at GS31.
  • At Minnipa, an increase of up to 31% grain yield to 3 t/ha over the control was achieved by adding extra irrigation (50 mm) at GS31 and applying 120 kg N/ha in two split applications of 60 kg/ha at emergence and by GS31.
  • Water use efficiency (WUE) improved with N fertilisation by GS31 at Minnipa and Cummins.
  • The split application of 120 kg N by GS31 may only be a good investment in paddocks where crops with N requirements (e.g. canola) were grown in the previous season or soil N at sowing was low (less than 44 kg/ha) and with average or above average seasonal soil moisture at GS31.
Lead research organisation South Australian Research and Development Institute
Host research organisation N/A
Trial funding source GRDC DAS00165
Related program N/A

The present project is part of the bi-lateral investment initiative between SARDI and GRDC (scope study DAS00165). Special thanks to Douglas Green, Ian Burrows and Jake Hull for providing their land for field trials in Cummins, Lock and Minnipa. Thank you to Brenton Spriggs, Sue Budarick and Katrina Brands for their collaboration with field activities.

Other trial partners Not specified
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Crop type Wheat
Treatment type(s)
  • Fertiliser: Rate
  • Variety: Type
Trial type Experimental
Trial design Replicated

Minnipa Agricultural Centre 2018

Sow rate or Target density Scepter, Mace, Halberd and Spear
Sow date 22 May 2018
Harvest date 13 November 2018
Plot size 5 m x 1.6 m
Plot replication 3
Plot blocking randomised complete block design
Plot randomisation randomised complete block design
Paddock history 2017: Banker canola 2016: Buloke barley 2015: Wyalkatchem wheat

86 kg/ha Triple Super Phosphate

Mineral N in control treatments were 74 kg/ha for Minnipa, 61 kg/ha for Lock and 44 kg/ha for Cummins. Rainfall from sowing up to harvest was 178 mm at Minnipa, 231 mm at Lock and 288 mm at Cummins.

Treatment applications were based on extra N (two applications of 60 kg/ha each of N as urea at emergence and GS31) and water (50 mm applied at the beginning of stem elongation).


Boxer gold 1.5 L/ha, Avadex® 1.5 L/ha, Treflan 1.7 L/ha, Round up 2 L/ha, Hammer 100 ml/ha, Sulphate Ammonia 800 g/ha

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Trial source data and summary not available
Check the trial report PDF for trial results.
Observed trial site soil information
Trial site soil testing
Not specified
Soil conditions
Trial site Soil texture
Site 6, Minnipa Agricultural Centre, SA Red sandy clay loam
Derived trial site soil information
Australian Soil Classification Source
Trial site Soil order
Site 6, Minnipa Agricultural Centre, SA Anthroposol
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



Site 6, Minnipa Agricultural Centre SA 2018

Observed climate information

Rainfall avg ann (mm) 325mm
Rainfall avg gsr (mm) 241mm
Rainfall trial total (mm) 269mm
Rainfall trial gsr (mm) 208mm

Derived climate information

Site 6, Minnipa Agricultural Centre SA


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: 13-05-2019 12:17pm AEST