Sustainable agricultural systems for the twenty-first century: the role of mineral fertilizers

abonos fosfatados abonos nitrogenados abonos npk abonos potasicos absorption de substances nutritives crop yield engrais npk engrais potassique environmental impact fertilisation fertilizer application impact sur l'environnement impacto ambiental nitrogen fertilizers npk fertilizers nutrient uptake phosphate fertilizers potash fertilizers rendement des cultures rendimiento de cultivos