Positive effects of sulphur fertilisation on grasslands yields and quality in Belgium

Atmospheric sulphur (S) depositions have been decreasing in Europe for the past 20 years. Up to now, there were no evidences of S deficiencies on cut grasslands in Belgium. The effects of S fertilisations together with incremental nitrogen (N) dressings were investigated in Belgium using small plot trials on cut grassland between 2001 and 2003. In 4 cases out of 13, S supply increased dry matter yields on average by 0.8 t ha−1 y−1. Response to S appeared to depend on the site, the year, the N fertilisation level and the soil. Grass S content was significantly increased and N:S ratio decreased by S fertilisation. High N:S ratio (>14) was observed in grasslands without S fertilisation even with a moderate N supply. It is concluded that S deficiency can be feared for cut grassland in Belgium mainly on light textured soils after a wet winter.