The following distinguishes between the role of Sulphur in livestock and Sulphur in soil and crops.
Sulphur in animals
Sulphur (S) has an important role in protein production, both in animals and plants, because it is a component of Sulphur-containing amino acids (methionine and cysteine). In ruminants, therefore, it is essential in the production of microbial protein. In addition, Sulphur is a component of the B vitamins thiamine and biotin, among others, and of the hormone insulin.
|g/kg dry matter
|Young cattle from 4 months
|Young cattle from 9 months
|Young cattle from 16 months
|Dry 8-3 wks to calving
|Dry 3-0 wks to calving
|Lactating (20 kg)
|Lactating (40 kg)
A Sulphur deficiency results in specific symptoms such as reduced feed intake and production due to reduced rumen microbial activity. Other symptoms that can be observed are a dull hair coat, salivation, and moist eyes.
A Sulphur excess can occur relatively easily; symptoms can already occur at 3-4 g/kg dry matter. The CVB (2005) indicates a toxicity limit for Sulphur of 4 g/kg dry matter (at chronically high levels). An acute excess of Sulphur (in the form of Sulphite) affects the nervous system and leads to intestinal inflammation, blindness, muscle twitching, diarrhea and dehydration, lung and kidney damage, and bleeding. In the form of Sulphate, the symptoms are less severe and, most prominently, osmotic diarrhea occurs. When the Sulphate excess is chronic, copper deficiency may also occur.
Sulphur in soil and crop
Sulphur is an essential component of protein formation and as such is important for grass growth, needed in larger quantities. With sufficient Sulphur, nitrogen utilization is better and lower nitrate levels are found. Sulphur deficiency, like nitrogen, leads to lower dry matter yields. Deficiencies occur mainly in the first cuts of the season.
Sulphur supply has declined significantly in the last 10 years due to lower Sulphur emissions from industry and little use of Sulphur fertilizers. Sulphur supply now occurs primarily through the mineralization of organic matter. The other minor supply items are deposition (precipitation from the air), capillary rise from the soil and animal manure and, as an outflow item, leaching.
The most important supply item 'mineralization' can be determined by having an S-total determination carried out via the Fertilization Manager from Eurofins Agro. The S-total determines how much Sulphur is available in the first three cuts, called SLV (Sulphur supplying capacity, similar in structure to NLV). If the SLV, along with the smaller supply and removal items, is lower than the needs of the grass, then a supplementary application of fertilizer is required. The required amount is advised over the first two cuts. No shortages are then to be expected for the rest of the season.
A product with a high Sulphur content is potato press fiber (>10 g/kg dry matter). Corn silage, CCM and pressed beet pulp contain low levels, while grass and grass silage are between (3-4 g/kg dry matter).