Response of selected lucerne varieties to the way of stand establishment

age avena sativa chemical composition composition chimique crop yield cultivos de primavera culture de printemps edad ensemencement establecimiento de plantas facteur de rendement factores de rendimiento hordeum vulgare medicago sativa nurse crops plant establishment planta-abrigo plante d'abri rendement des cultures rendimiento de cultivos siembra sowing spring crops variedades varieties yield factors