Nitrate in nature: product of soil cover

abonos abonos nitrogenados abonos npk abonos pk agricultural soils azote engrais engrais npk engrais pk fertilizers geographical information systems mineralisation mineralization modele modelos models nitrate nitrates nitratos nitrification nitrogen nitrogen fertilizers npk fertilizers phosphorus potassium fertilizers soil types sol agricole tipos de suelos type de sol vegetation