Geoscience Reference
In-Depth Information
Sulphur is removed from the soil by harvesting or grazing plants, and by
leaching. As sulphur does not readily attach to soil and clay particles it is much
more prone to leaching than phosphorus, calcium or magnesium, especially on
sandy soils. It is also removed by erosion of topsoil by wind or water.
Sulphur may be added to the soil using sulphur rich fertilisers or gypsum and
if near or downwind of industrial areas, rainfall may add significant amounts as
acid rain. Some irrigation water may also contain sulphur, especially from some
groundwater bores.
Sulphur in plants
Sulphur is present in every plant cell in association with nitrogen as proteins, and
helps chlorophyll to be formed by the plant. It is also present in plant vitamins and
enzymes. If sulphur levels are low then plant growth will be poor, resulting in slow
growing, pale, spindly plants.
Sulphur deficiency symptoms
Young plants generally have a light green colour, are stunted, mature late, do not
branch normally and are spindly. Grasses may show striping of the upper leaves.
Deficiency symptoms may disappear later in the growing season as soil bacteria
release sulphur previously unavailable to the plant. Deficiency signs may appear in
legumes before they do in grasses.
Sulphur in animals
Cattle and sheep require sulphur to produce meat, milk and wool for the
production of vitamins and the function of enzymes. It is present in muscle,
cartilage, bone, tendons, walls of blood vessels, and is also found in bile and blood
anticoagulants.
It is important in detoxifying many substances produced in the body. Sulphur
also increases the feed conversion efficiency of ruminants by up to 25%, or
conversely, lack of sulphur in the feed can reduce conversion efficiencies by up to
25%.
Soil tests
Laboratories can test for soil total sulphur, or plant available sulphur content. The
total sulphur test is the quantity of sulphur that may become available over time,
but not all of it is immediately available to plants due to the cyclic nature of
sulphur availability.
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