Sulphur is an essential nutrient for all plants and animals. Its behaviour in the soil is very similar to that of nitrogen.
In other words, high rainfall can lead to leaching. This, in turn could lead to sulphur deficiencies despite attempts to avoid this.
Sulphur is known to be important for yield and quality. However there is strengthening evidence to suggest that the chemical element has an important relationship with a large number of other nutrients.
So, ensuring an adequate supply of sulphur through the growing season could be key to ensuring these other nutrients are taken up efficiently also.
According to the Potash Development Association (PDA), sulphur is an essential nutrient for all plants and animals, with some crops more vulnerable to deficiency than others.
Historically, sulphur was deposited on land from the atmosphere in adequate quantities for optimal crop growth and development.
However, this scenario has changed radically with the ever lessening use of coal in power stations and domestic fires.
It is now estimated that between 1.0kg/ha and 3.0kg/ha of sulphur are deposited on land from the atmosphere on an annual basis.
These levels are well below what would have previously been the case.
As a result of this reduction, soils are now showing critical signs of deficiency and applications of sulphur to crops has become an essential part of nutrient management planning on farms.
Sulphur in the soil behaves in a similar way to nitrogen. It becomes plant-available from the breakdown of organic matter, and to some extent from soil minerals.
Soils which are organic or heavy textured are more able to supply sulphur than light and inorganic soils.
Plants take up sulphur in the form of the sulphate anion. These predominate in the soil solution, which means they are at risk of leeching depending on the soil texture and rainfall.
This risk must be taken into account when nutrient planning.
Available levels of sulphur in the soil can be accurately assessed by laboratory analysis.
However, its variability both down and across the soil profile and over time, means that the normal four yearly soil analysis for pH, phosphate, potash, and magnesium is not appropriate.
It has been the usual practice to apply a readily soluble source of sulphate in the early spring in the expectation that it will provide sulphur throughout the growing season.
However, there are now doubts that taking this approach will not always satisfy crop need.
Given this scenario, the PDA is highlighting the need for tillage farmers to ensure that sufficient sulphur is available to crops throughout the growing season.
