Sulfur is an essential nutrient, but how much do we need?

Canola is often regarded as having a high requirement for sulfur (S), but does it? 

Analysis of plant tissue samples and a lack of response in most CSBP canola trials indicates that deficiencies are rare. And analysis of canola grain from many trials shows that S removal rates are not as high as often thought.

CSBP has tested for S responses in thirteen canola trials since 2008 (Figure 1). Of these, only two have produced yield responses (Manypeaks, 2010 and Cunderdin, 2017). Both sites had very low levels of S in the top 30 cm of soil (2 mg/kg), and plant testing confirmed deficiencies.

 

Figure 1. Canola yields with and without sulfur applications in CSBP trials 2008 – 2018. Trials marked * denote a significant response.

High yields (3.5 t/ha) were grown at Condingup (2008) and Mount Barker (2018) without any S applied!

Analysis of seed also indicates that many Growers are over-applying S with only about 4 kg of S being removed in every tonne of yield.

Sulfur is known to be important for seed oil formation in canola, but interestingly, S supply did not affect oil concentrations in the ten trials which were analysed.

 

Sulfur is an essential nutrient, but applications are often excessive and an unnecessary cost.

 
James Easton
By James Easton
- Senior Agronomist

James has over 30 years’ experience working on soil and plant nutrition (crops and pastures).

He graduated from the University of Western Australia with a degree in Agricultural Science (Honours). He has in depth knowledge of historic fertiliser research trials and has worked closely with many growers, consultants, research institutions and farming groups over the years.

James gets a lot of satisfaction from sharing his knowledge with growers and those who support them. And he enjoys the fact that we are always learning.

Agronomic insights

Want to stay up to date? Have our latest research findings and news delivered to your inbox