What is Sulphur?
In agriculture and horticulture sulphate is the common term for nutrient forms of the element sulphur (S). Plants absorb sulphur from the soil in the sulphate form (SO42-).
Sulphur in Nature
Sulphur occurs naturally in the environment and is the thirteenth most abundant element in the earth’s crust. It can be mined in its elemental form, though this production has reduced significantly in recent years. Most elemental sulphur is obtained as a by-product of removing sulphur containing contaminants from oil and gas production.
Elemental sulphur is produced all over the world. The largest producers are the United States, Canada, Russia, and West Asia.
Functions of Sulphur
Sulphur is an essential plant nutrient and is necessary for protein synthesis, to maintain the balance of amino and sulphur-containing compounds. Due to the central role of both sulphur and nitrogen in the synthesis of proteins, the supplies of these nutrients in plants are highly inter-related and a shortage in the availability of sulphur will reduce the efficiency of nitrogen use.
As well as protein synthesis sulphur is essential for plants to form enzymes, vitamins, and chlorophyll. In legumes, it is crucial in nodule development and efficient nitrogen fixation and is critical for determining the nutritional quality of foods.
Human Needs
Sulphur is the third most abundant mineral in human bodies found in amino acids used to make proteins and are present in skin, hair and nails. Foods that are high in animal or plant-based proteins are a good source of sulphur. An adult human requires around 1-2grams/day.
Sulphur in Plants & the Environment
To ensure healthy and nutritious plant growth, adequate supplies of sulphur must be maintained as aerial deposition has declined dramatically. Sulphate in the soil is liable to leaching, like nitrates, therefore annual applications are usually essential, whether through fertilisers, manures or a mixture of both.
Sulphates contribute to acidification of surface water and soil and contribute to acid rain and fog that damage ecosystems, forests and plants.