Computer-aided model system N-PROG for estimating the requirements of nitrogen, crop yields and post-harvest nitrogen residues with respect to ecological parameters, economic and crop management factors

abonos nitrogenados azote cereales cereals conduite de la culture crop management ensayo hiver invierno leaching lessivage du sol manejo del cultivo modele modelos models nitrogen nitrogen fertilizers rendement rendimiento residues residuos statistical methods testage testing weather winter yields