The effect of sulphur application on yield, sulphur content and N/S-ratio of grasses for silage at six sites in Finland

abonos azote azufre crop yield dactylis glomerata engrais ensilado ensilage (produit) feed grasses fertilizers festuca pratensis finland finlande finlandia nitrogen phleum pratense rendement des cultures rendimiento de cultivos silage soufre sulphur