Effect of the regeneration nitrogen rate on soils with different contents of inorganic nitrogen

catch cropping cultivo intermedio cultivos de invierno cultivos de primavera culture d'hiver culture de printemps environmental factors essai facteur du milieu factores ambientales hordeum vulgare medicago sativa muestreo nitrogen content pruebas sampling site factors spring crops teneur en azote trials triticum aestivum winter crops