Nitrogen and potassium fertilization of leys in northern Norway. I. Yields and soil analyses

abonado fraccionado abonos nitrogenados abonos potasicos analyse de sol azote contenido de materia seca crop yield dry matter content encamado engrais potassique leys lodging nitrogen nitrogen fertilizers noruega norway phleum pratense potash fertilizers potasio potassium pradera temporal prairie temporaire primavera printemps rendement des cultures rendimiento de cultivos soil testing soil types split dressings spring tipos de suelos type de sol verse