Mineral or chemical fertilisers
Mineral salts and other chemical compounds produced by industrial method, added to soil in order to supply nutrients and to supplement certain elements taken up by plants. They are intended for pre-sowing or top dressing.
Mineral or chemical fertilisers are divided into:
- nitrogen fertilisers - e.g. Norwegian saltpeter, soda nitrate, ammonium nitrate, nitro-chalk, urea; contain active nitroanion; the main semi-products used to produce nitrogen fertilisers are ammonia (NH3) and nitric acid (HNO3),
- phosphatic fertilisers - e.g. super-phosphate, super Thomas phosphate and Thomas phosphate; contain phosphorus available to plants. Phosphatic fertilisers are obtained from minerals such as apatite of magmatic origin and phosphate rocks of secondary, sedimentary origin.
- potassic fertilisers - salts of potassium, e.g. potassium sulphate, kainite; contain potassium available to plants. Potassic fertilisers are obtained from minerals containing potassium salts,
- mixed fertilisers - containing several elements essential for plants in available form, mixed with chalk, gypsum or with other substances, e.g. Nitrofoska (Polish trade name for a line of highly concentrated fertilisers), ammonium chloride.