Sulphur: The last piece of the jigsaw puzzle

Sulphur (S) and nitrogen (N) go hand-in-hand when it comes to maximising grass production and sward quality during the grazing season.

In the past, S was overlooked as an essential nutrient to include in your fertiliser plan; but, farmers are beginning to come to the realisation that S is just as important as N to the grass plant.

In addition to N, S is involved in protein synthesis in the grass plant. Both elements are the building blocks of amino acids which form plant protein.

If S is the limiting nutrient, protein production is compromised as the grass plant cannot produce amino acids with N on its own.

It is important to have the right balance of N and S in the soil, as it is essential for getting the most efficient use out of your N fertiliser.

Does my grass need sulphur?

If you feel you are not getting as much of a response from your N fertiliser as you should be, this may be a clear sign of S deficiency in the soil.

In addition, pale-yellow leaves similar to what is observed when there is a N deficiency is an indicator. Although, it is usually more visible in younger plant leaves when associated with S.

The most effective way of accessing the S content of your grass is through a herbage analysis.

Fertiliser recommendations

Stan Lalor – head of specialty business in Grassland Agro – recommends applying fertiliser at a ratio of approximately 12:1, as a target to keep N and S in balance across the year.

So, if you are applying 250kg/ha across the year, then 20kg/ha of S (16 units/ac) should be applied.

However, it is important that these applications are split into three-to-four applications across the grazing season – once in spring, twice during the April-to-July period and finally once after August.

So, when purchasing fertiliser this year, be mindful of the plants need for S and purchase an N fertiliser which contains a percentage of S.