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LCF Australia

Nutrient guide

Sulphur (S)

Needed to turn nitrogen into protein. Canola needs much more than cereals, and sulphate leaches from light soils.

What sulphur does

Sulphur is part of several amino acids, so plants need it to make protein from the nitrogen they take up. A crop short of sulphur cannot use nitrogen fully, however much nitrogen is applied.

Signs of deficiency

Sulphur moves less freely within the plant than nitrogen, so yellowing often starts in the younger leaves. In canola, leaves can cup and show purple tints, and flowers may be pale. In pasture, sulphur deficiency is easily mistaken for nitrogen deficiency.

Where it is often short

Plants take up sulphur as sulphate, which moves with soil water. Shortages are more likely on sandy, low organic-matter soils, after heavy rain, and in paddocks that have had little sulphur-containing fertiliser.

Sources

  • Ammonium sulphate and sulphate of potash.
  • Gypsum, which also supplies calcium.
  • Sulphate micronutrients such as zinc sulphate and manganese sulphate, which supply sulphur along with the trace element.
  • Nitrogen fertilisers with sulphur included, such as Urea Plus (7.5% sulphur).

Crop guides

What sulphur deficiency looks like

Photos of deficiency symptoms. Where we do not yet have a suitable photo, we will add our own trial photo. Symptoms vary with crop, variety, soil and season.

  • A young maize seedling in soil whose youngest leaves are pale yellow
    Sulphur deficiency in young maize: yellowing shows first on the youngest leaves. Photo: C. Crozier, SoilScience.info, CC BY 2.0, via Flickr.
  • Sulphur deficiency in canola. We will add our own trial photo here.

Photos may show other crops with the same symptom. Full credits: Image credits.

How LCF products fit

LCF Australia supplies compound fertilisers made by our manufacturing partner Lardmee (LDM), including Urea Plus and zinc and manganese sulphates, on enquiry. We also supply the Field Spears soil testing kit, which reads soil N, P, K and pH in the paddock. Which product suits, how much and when depends on the soil, the crop, the season and how you apply it.