Intercropping of soybean and maize for silage in Northern Italy: effect of nitrogen level and plant density on growth, yield and protein content

abonos nitrogenados application rates azote contenido proteico crecimiento croissance crop yield cultivo intercalado culture intercalaire dose d'application feed crops fertilidad del suelo forraje verde fourrage vert glycine max green feed growth intercropping nitrogen nitrogen fertilizers plantas forrajeras population density protein content rendement des cultures rendimiento de cultivos soil fertility zea mays