Role in the plant: Sulfur is a structural component of some amino acids (including cystein and methionine) and vitamins, and is essential for chloroplast growth and function; it is found in the iron-sulfur complexes of the electron transport chains in photosynthesis. It is needed for N2 fixation by legumes, and the conversion of nitrate into amino acids and then into protein.
Deficiency symptoms: Yellowing of predominantly the younger (top) leaves of the plants. According to Yara International in brassicas, the margins of the leaves curl and redden.
Toxicity symptoms: not known.
Soils that have sulphur most prevalent: Soils with high organic matter.
Management remarks: The availability of sulfur reduces as the soil pH becomes more acidic. Sulfur is also easily leached and should be added in small quantities and frequently, particularly on sandy soils.