The effect of undersown cover crops on grain yield and the nitrogen content of plants and soil

abonos nitrogenados application rates calidad cover plants crop yield dose d'application grain granos hordeum vulgare loam soils lolium multiflorum nitrogen content nitrogen fertilizers noruega norway peso plant soil relations plantas de cobertura plante de couverture poids quality relaciones planta suelo relation plante sol rendement des cultures rendimiento de cultivos sol sablolimoneux suelo franco teneur en azote trifolium repens weight