What are the common methods for identifying fertilizers? Teach you to quickly tell real from fake

1. Urea: The appearance is granular or crystalline, easily absorbs moisture, deliquesces by absorbing water from the air, and is easily soluble in water and ammonia water. Place a piece of iron sheet on a stove, put urea granules on it, and the urea will quickly melt and volatilize, with a little white smoke at the same time, and an ammonia smell can be detected. The total nitrogen content for agricultural use (calculated on a dry basis) is 46.0%.

2. Ammonium sulfate: The appearance is white or light-colored crystals, easily absorbs moisture, and is easily soluble in water; the aqueous solution is acidic. It absorbs heat when dissolved in water, releases ammonia gas when reacting with alkalis, and melts relatively slowly when heated over fire compared with urea, ammonium nitrate, and ammonium chloride. It can also be identified by the white precipitate formed when barium chloride reacts with ammonium sulfate in aqueous solution. The ammonia content for agricultural use (calculated on a dry basis) is 21.0% for first-grade product and 20.8% for second-grade product.

3. Ammonium nitrate: The appearance is white or slightly yellow, easily soluble in water, while absorbing a large amount of heat and lowering the water temperature, and it has strong moisture absorption and caking properties. A large amount of ammonium nitrate decomposes when heated and can burn or even explode, with white smoke produced, and an ammonia smell can be detected. The total nitrogen content for agricultural use (calculated on a dry basis) is 34.4%-34.6%.

4. Ammonium chloride: The appearance is white or slightly yellow crystals, easily soluble in water, and its solubility increases significantly as the temperature rises; it has strong moisture absorption, easily cakes, and its aqueous solution is acidic. Place a small amount of ammonium chloride over fire and heat it, and a strong pungent odor can be detected, accompanied by white smoke; the ammonium chloride will quickly melt and disappear completely, and during the melting process the unmelted part can be seen to be yellow. The total nitrogen content for agricultural use (calculated on a dry basis) is 25%.

5. Agricultural ammonium bicarbonate: The appearance is white or slightly gray crystals, with an ammonia odor, strong moisture absorption, easily soluble in water, and the aqueous solution is weakly acidic. For identification, take a small amount of sample with your fingers and rub it, and a relatively strong ammonia odor can be detected. The nitrogen content for agricultural use is 17%.

6. Superphosphate: The appearance is a loose powdery substance in dark gray, grayish white, light yellow, etc., with a slight sour smell; it is an acidic chemical fertilizer, sensitive to the action of alkalis, and easily loses its fertilizer efficiency. Part of it can dissolve in water, and the aqueous solution is acidic. Under normal conditions its moisture absorption is relatively small; if the air humidity reaches above 80%, it absorbs moisture and forms hard lumps. The premium grade contains 20% available phosphorus pentoxide, grade four A contains 13%, and B contains 12%.

7. Calcium magnesium phosphate fertilizer: The appearance is grayish white, grayish green, or grayish black powder; the powder is extremely fine, and under sunlight, crushed glass-like objects can generally be seen and glisten. It is insoluble in water, not easily lost, non-hygroscopic, non-toxic, and non-corrosive; when heated over fire, no change can be seen, and its melting point is about 135°C. The premium grade contains 20% available phosphorus pentoxide, 40% calcium oxide, and 12% magnesium oxide.

8. Compound fertilizer: The appearance is grayish brown or grayish white granular. Some compound fertilizers contain white granular crystals of incompletely crushed urea, and some compound fertilizers also contain whole urea crystals existing separately. It has slight moisture absorption, and after absorbing moisture the compound fertilizer granules are easily crushed. Non-toxic, odorless, and non-corrosive; the nitrogen fertilizer, potassium fertilizer, and the water-soluble phosphorus in some phosphate fertilizers in compound fertilizer can dissolve in water. When heated over fire, white smoke can be seen, and an ammonia odor can be detected, and it cannot all melt.

9. Ammonia water: It is an aqueous solution of ammonia gas dissolved in water, a colorless transparent or slightly yellow liquid, with a strong pungent odor, and toxic. The aqueous solution is weakly alkaline. The ammonia content in agricultural ammonia water is generally 15%.