Ammonium Sulfate for Canola in Southeastern Australia

Evaluation of ammonium sulfate as a S source for rainfed wheat and canola cropping systems.


Most growers recognize that canola has a much higher demand for sulfur than cereals, with the oilseed having almost three times the grain S concentration compared to wheat. To meet this demand, many growers use low rates of gypsum (calcium sulfate) applied before sowing, and then meeting the N demand with a combination of at-sowing and topdressed urea. Read more

Year of initiation:2010
Year of completion:2013


07 Aug 2015

Supplying sulfur in cropping systems
Rob Norton & Elaina VanderMark

01 Sep 2014

Sulfur deficiency in canola
Taken at Bealiba, Victoria

30 Jul 2013

Sulfur - Known knowns, known unknowns
Presentation at Agronomy Community Meetings

23 Aug 2012

Best practice management of nitrogen and sulfur for canola and cereals – the Mallee.

21 Jun 2011

Balanced nutrition in Brassica napus production with emphasis on S fertilizer requirements
Paper presented at the 13th International Rapeseed Congress, June, 2011.

13 Feb 2011

What sulphur source should I use?
Discussion of the various sources of S for crops and pastures.

30 Aug 2010

Addressing sulphur needs in-crop
Sulphur is an important part of a balanced crop nutrition program and this is a summary of options for in-crop S application.

08 Apr 2010

Sulphur for canola in 2010
Canola growers are advised to check to make sure S does not limit yields in 2010

01 Feb 2010

Ammonium Sulfate as a specialty fertilizer for canola
Research update to investigate better ways in meet the S and N needs of canola.

Interpretive Summary

In alkaline-calcareous soils of southeastern Australia (Calcarosols), the main N fertilizer sources are either urea or ammonium sulfate (AS) in cereal and oilseed cropping systems. The relatively low N recovery in these systems is most likely associated with ammonia volatilization. In addition, S from AS may be immobilized by chemical precipitation with Ca, which may result in S deficiency, thereby reducing the N recovery further.

The importance of N and S in canola cropping systems is well established. However, in the past, urea and gypsum were the commonly used strategies for N and S nutrition. We hypothesized that the use of ammonium sulphate (AS) along with urea may enhance both N and S efficiencies in a Calcarosol growing canola. We conducted a field experiment to investigate the effects of combining urea and AS on canola growth, yield and nutrient uptake at Walpeup in southeastern Australia.

In cropping systems, the importance of N and S nutrition has been clearly established, particularly for canola. The usual strategy has been to pre-spread gypsum and drill urea in at sowing to meet these demands. It was hypothesized that the use of ammonium sulfate along with urea may enhance both N and S efficiency in calcarosol.

Two field sites were sown to canola with varying rates of N and S supplied either as ammonium sulphate or urea plus gypsum. The Mallee site had a soil S test level (to 10 cm) of 2. 7 mg/kg (KCl40) while the Wimmera site had a S soil test of 2. 1 mg/kg. At these levels, both sites should have been responsive to applied S for both canola and wheat, but the grain yield results showed a significant response to S only at the Wimmera site.

This project is investigating the role ammonium sulfate (AS) can play as a fertilizer for cropping systems in southeast Australia. A pot experiment showed that after 42 days, compared to the control, AS gave a 104% growth response compared to urea/gypsum (61%) in canola. When a similar experiment was conducted using wheat as the test crop, AS and the urea/gypsum application produced similar responses.

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Updates & Reports


Project Description

Sulfur deficiency in canola

Project Leader

Rob Norton, International Plant Nutrition Institute (IPNI)

Project Cooperators

MT Khan, The University of Melbourne
Robert Edis, The University of Melbourne
Deli Chen, The University of Melbourne
Charlie Walker, Incitec Pivot Ltd.

IPNI Staff

R. M. Norton


Oceania \ Australia and New Zealand \ AUS \ Victoria \ Wimmera

Oceania \ Australia and New Zealand \ AUS \ Victoria \ Mallee


4r source, nutrient management

rapeseed (canola), wheat

Nitrogen (N), Sulfur (S)