Productivity and nutritive value of legume-grass mixture depending on utilization system

botanical composition composition botanique compound feeds contenido proteico crude fibre cultivo mixto especies feed grasses fibra bruta fibre brute field experimentation grazing legumes leguminosas methode methods mixed cropping nutritive value pastoreo piensos compuestos poland pologne polonia productividad productivity protein content soil texture species statistical methods textura del suelo texture du sol uses usos utilisation valeur nutritive valor nutritivo