The Importance of Sulfur in Plant Nutrition

Sulfur (S) is an important plant nutrient essential to produce healthy plants with high yields. No matter the crop, fruit, vegetables, grains, or pasture crops, they all need sulfur to reach their full yield potential.

Historical Sulfur Sources

Historically, plants received much of their sulfur requirements from industrial processes that released sulfur into the atmosphere. But changing legislation to improve air quality has reduced atmospheric sulfur, limiting the availability of sulfur for plants. Combine this with the increasing scale of agriculture, removing more sulfur from the soil, and the need for effective sulfur fertilizers is clear.

The Role of Sulfur in Plants

Sulfur is essential for plants to form proteins, enzymes, vitamins, and chlorophyll. In legumes, it is crucial in nodule development and efficient nitrogen fixation.

Protein synthesis requires large amounts of sulfur, especially for the formation of oils within the seed. As a constituent of several amino acids and vitamins found in plants and animals, sulfur is critical for determining the nutritional quality of foods.

Sulfur is also essential for photosynthesis and contributes to crop winter hardiness. An adequate supply of sulfur is crucial, not only for crops with high sulfur requirements – such as legumes (alfalfa, clover, soybean, etc.) and Cruciferae (canola and rapeseed) – but also for crops with high nitrogen requirements (maize and cotton), which require sulfur to optimize their nitrogen utilization.

Symptoms of Sulfur Deficiency

Pale green leaves, starting first on younger leaves, indicate sulfur deficiency. Eventually, the whole plant will have a light yellow-green appearance. Plants displaying sulfur deficiency often appear smaller with stunted growth.