Sulphur is an essential nutrient that fulfils various important functions in plants, including the formation of amino acids, proteins, chlorophyll and the support of nitrogen uptake, e.g. in legumes. A lack of sulphur not only impairs plant growth, but also quality and resistance to disease. In addition, the S supply is strongly influenced by soil and hydrological factors. The sulphur content of the atmosphere due to industrial combustion has fallen sharply in recent decades, which has ultimately led to a drop in S levels in the soil and also in certain plant species, initially in conventional farming and later particularly in organic farming. As a result, there has been a great increase in research into the causes and ways and means of improving yield and quality deficiencies on farms. In this summarised study, data from 98 sites in Central Europe (Germany, Austria, Sweden, Norway, Denmark, Belgium, Italy, Poland, Great Britain) were recorded from 1998 to 2023. The sulphur fertiliser trials were conducted on farms and experimental stations under organic farming conditions. 1169 treatment variants and 598 standard variants without or with reduced S-fertilisation were analysed. Fertilisation was carried out with various sources of sulphur, including kieserite, gypsum, elemental sulphur, epsom salt and other types, in different quantities and forms, usually directly before or during crop cultivation. Soil analyses were done according to VDLUFA specifications in Germany or comparable standards in Central Europe. The amounts of plant-available S in the soil were determined at depths of 0–30 cm, 30–60 cm and 60–90 cm. Site characteristics such as Smin, Nmin, soil type, pH value, precipitation and the extent of livestock farming were recorded. A sufficient amount of data was available for each experimental aspect to quantitatively describe the influence of increasing S supply to the soil or plant species groups (permanent grassland, lucerne-clover-grass, grain legumes, cereals) from severe deficiency to oversupply. The analyses therefore focused on establishing relationships between yield responses, correlations with the nitrogen uptake of crop species and N2 fixation in legumes and the nutrient supply with plant-available sulphur. The aim of these investigations was to develop assessment methods for the soil supply with available sulphur to achieve optimum DM yields. The results were also used to develop practical methods for determining fertiliser requirements for different crop species in organic farming.