Nitrogen and potassium fertilization of leys in northern Norway. II. Chemical and in vitro analyses of the forage

abonado fraccionado abonos nitrogenados abonos potasicos azote chemical composition composition chimique composition globale digestibilidad digestibility digestible fibre engrais potassique feed grasses fibra asimilable fibre digestible in vitro experimentation leys nitrogen nitrogen fertilizers noruega norway phleum pratense potash fertilizers potasio potassium pradera temporal prairie temporaire proximate composition soil types split dressings tipos de suelos type de sol