Nitrogen and potassium fertilizer treatments to timothy, brome grass and cocksfoot in southeastern Norway

abonos nitrogenados abonos potasicos analyse statistique bromus inermis contenido de materia seca crop yield dactylis glomerata dry matter content encamado engrais potassique grasslands herbage lodging malezas mauvaise herbe nitrogen fertilizers noruega norway ph phleum pratense potash fertilizers praderas rendement des cultures rendimiento de cultivos soil sol statistical analysis suelo verse weeds