Test gauges essential building block

A new test for soil sulphur is helping farmers more efficiently target their fertiliser use.

The Total Sulphur Test (Total S) was developed by AgResearch nearly six years ago, and has now been commercialised in partnership with Hill Laboratories.

Sulphur is an essential element for growing plants, it is a component of plant proteins and has an important role in the synthesis of chlorophyll. It is also essential for all protein synthesis in mammalian systems and is important in the formation of milk proteins and the proteins that make up hair and wool.

Sulphur deficiency in plants manifests itself in pale, yellow leaves; similar symptoms to those found in nitrogen deficiency.

This test is a measure of the total pool of all forms of sulphur in soil. It is less prone to both spatial and seasonal variability and less affected by dung and urine patches. It was developed to overcome the uncertainties of previous tests about the amount of sulphur in the soil available for plant uptake.

AgResearch scientist Dr Anwar Ghani, who developed the test, says that it gives farmers a clear indication of whether or not they need to add sulphur to their pastures.

“Many farmers use superphosphate which has phosphorus and sulphur together in order to take care of any sulphur deficiency. If your soil doesn’t actually need it, then you are putting that sulphur on for no reason, and it’s wasted,” he says.

“If you’ve done the test you will know how your soils would potentially respond to adding sulphur and whether you will have a reasonable supply of sulphur for growing plants.

“The test gives you both the security of knowing you have no deficiencies and the option to make decisions as to where else can you take your sulphur dollar if you know where it’s not needed.”