S-index (Sulphur)
The S-Index provides an instant indication of the sulphur availability relative to the actual grass yield. This insight helps optimise sulphur fertilisation in the following growing season to produce high-quality forage protein, increasing self-sufficiency and protein efficiency on the farm.
Sulphur (S) is vital for amino acid synthesis and thus affects forage protein quality. Productive grassland requires 35–45 kg of S (85–115 kg SO₃) per hectare. Field trials show that sulphur deficiency can reduce yields by 10–20%. Excess sulphur, on the other hand, can impair copper (Cu) and selenium (Se) uptake, leading to animal health issues.
Interpreting the S-Index
Understanding sulphur supply in relation to grass growth allows farmers to adjust fertilisation strategies to improve protein yield and quality. Eurofins Agro’s S-Index evaluates protein composition, cell wall content in relation to maturity, and sulphur levels.
More information about the S-index, you can find in the video below: