Importance of Sulphur on grassland

Importance of Sulphur on Grassland

Close to 90% of the utilisable agricultural area in Ireland is under grass. Our ability to utilise grass and clover here on the island of Ireland gives us a natural competitive advantage over a lot of our European competitors in our livestock production systems. It is key we make the best use of this natural advantage through good soil husbandry practices.

When we think about what fertiliser we are going to use on our farms, we often forget about the importance sulphur has as an essential nutrient for grass growth. Both in Ireland and in the EU, S levels are decreasing, and they are projected to decrease further in the years ahead. Sulphur deficiencies can lead to a reduction in the quality and quantity of grass which is being produced on our farms and its use is often overlooked as we attempt to get the lime, Nitrogen (N), Phosphorous (P), and Potassium (K) to the required levels. However, sulphur is essential for the formation of plant proteins, amino acids, some vitamins and enzymes. A sulphur deficiency will appear like a Nitrogen deficiency as the plants will start to show a pale yellow colour. A sulphur deficiency will start to affect the youngest leaves of the plant first as the mobility of S in the plant is somewhat poor. Research suggests that Sulphur is closely associated with the Nitrogen Use Efficiency and uptake of N in our grassland. It is essential we think about the inclusion of sulphur as you think about the purchase of chemical fertilizer from your local Liffey Mills store. Sandy, light soils are generally more prone to sulphur deficiencies, but the deficiency is not restricted exclusively to these soil types, and it is often the case that heavy soil types will suffer from sulphur deficiencies in early spring. Sulphur is applied as sulphate which is immediately available to the plants.

Therefore, it is of paramount importance that we take steps to rectify any sulphur deficiencies in our nutrient management plans or fertiliser programmes. The advice we are given when thinking about using sulphur in our fertiliser programmes is to use the little and often approach on grazed swards where 16 units of S is applied over the course of the year and where we start our programme in early spring. For the silage swards we must adopt a slightly more intensive approach. We require 16 units of S per cut on the silage fields. Sulphur can be applied in with a straight fertiliser or else in a compound fertiliser. Fertiliser can be added to fertiliser blends such as 18-6-12/ 10-10-20 and the levels of sulphur in some of these blends can range from 2 – 8%. Our Liffey Cut (25-2.5-10+4%S) is formulated with 4% sulphur, and our Liffey Graze (28-2.5-5+ 5%S + Ca + Mg) has 5% sulphur, and both compound fertilizers could be good options to consider as go through the growing season.

Contact your local Liffey Mills rep for any further information.

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