How to quickly identify counterfeit and shoddy fertilizers?

In rural areas, a few unscrupulous dealers go from village to village and door to door, using prizes as a cover to deceive farming households with counterfeit and shoddy fertilizers, affecting farmers' harvest for a whole season. In order to protect our own lawful rights and interests, today we will explain how to quickly identify counterfeit and shoddy fertilizers?

The methods for identifying fertilizer quality can be summarized in five words: look, feel, burn, test, and measure. The identification methods for several main types of fertilizers are introduced as follows:

(1) Nitrogen fertilizers. The counterfeit urea appearing on the market generally has ammonium bicarbonate at the bottom of the fertilizer bag and urea on top. Its characteristics are that the top layer flows well, while the bottom layer does not flow and may even cake, and a strong ammonia smell can be detected, so it can be judged to be fake urea mixed with ammonium bicarbonate. If both layers flow fairly well, and only the granule color and particle size are inconsistent, it is a mixture of urea and ammonium nitrate. The two can be further distinguished through the following three aspects.

① Appearance. Urea and ammonium nitrate are both odorless white granules. The difference is that urea appears as semi-transparent granules with no reflective surface; while ammonium nitrate granules have a shiny surface with obvious reflection;

② Feel. Urea is smooth and loose, with no damp feeling; ammonium nitrate is smooth and has a damp feeling;

③ Burning. Place the two substances on red-hot charcoal or an iron plate. Urea melts quickly, giving off white smoke with an ammonia smell; ammonium nitrate burns violently, emitting strong light and white smoke, accompanied by a “hissing” sound.

(2) Phosphate fertilizers. The main counterfeit substitutes for ordinary calcium superphosphate on the market include phosphogypsum, calcium magnesium phosphate fertilizer, and waste cement residue. The methods for distinguishing them are:

① Appearance. Ordinary calcium superphosphate is a dark gray or grayish-white to light gray loose powder with a sour smell; phosphogypsum is grayish-white hexagonal columnar crystals or crystalline powder with no sour smell; calcium magnesium phosphate fertilizer has no sour smell and appears as very dry glassy fine granules or fine powder; waste cement residue is gray powder particles with no luster, contains more hard substances, and after crushing the powder particles are also relatively coarse, with no sour smell; brick and tile powder is bluish in color, with relatively coarse powder particles and no sour smell;

② Feel. Ordinary calcium superphosphate is heavy in texture, feels soft and mealy but not light and fluffy; phosphogypsum is light in texture and feels soft and mealy, relatively dry; waste cement is heavier than ordinary calcium superphosphate, does not feel greasy, mealy, or dry to the touch, and has hard cement residue present;

③ Water solubility. Ordinary calcium superphosphate is partially soluble in water, while phosphogypsum and calcium magnesium phosphate fertilizer are difficult to dissolve in water, and waste cement powder added to water forms a slurry that solidifies again. During identification, if obvious impurities such as clods, stones, or coal cinders are found in ordinary calcium superphosphate, it is inferior ordinary calcium superphosphate; if the sour smell is too strong and there is more moisture, it is non-finished ordinary calcium superphosphate that has not been aged and is substandard.

(3) Potassium fertilizers. Common on the market is imported and domestically produced potassium fertilizer blended and then sold as imported potassium fertilizer; the color is white or red, and the blended potassium fertilizer flows poorly. Potassium sulfate blended with potassium chloride and potassium magnesium fertilizer is sold as potassium sulfate, and the blended potassium fertilizer appears as pale yellow and white or pale yellow and red crystals. In addition, sodium chloride (table salt) is also used to impersonate potassium chloride. Take a small amount of fertilizer and place it on a stove fire; if a purple-tinged flame appears, it is potassium chloride; if a yellow flame is produced, it is a counterfeit product.

(4) Compound fertilizers. On the market, granular ordinary calcium superphosphate is often used to impersonate ammonium phosphate nitrate and triple superphosphate, and ordinary calcium superphosphate and ammonium phosphate nitrate are also used to impersonate diammonium phosphate. They have similar colors, granules, and compressive strength, but their component types, contents, and prices differ greatly. Granular calcium superphosphate contains 14%-18% phosphorus; triple phosphate fertilizer (triple superphosphate) contains 40%-50% phosphorus; ammonium phosphate nitrate contains 20% nitrogen and 20% phosphorus; diammonium phosphate contains 46% phosphorus and 18% nitrogen.

① Appearance. When diammonium phosphate is not damp, the center is dark brown, the edges are slightly yellow, the outer edge of the granules has a slight semi-transparent feel, the surface is slightly smooth, and it appears as irregular granules; after dampening, the granule color deepens, with no yellow color or transparent edge feel, and after being soaked in water the granules look the same as dampened granules, with a very small amount of powdery white appearing on the surface. Ammonium phosphate nitrate has no obvious transparent feel, the granule surface is smooth, and it appears as dark brown irregular granules. Granular triple superphosphate is dark gray granules, while calcium superphosphate is lighter in color, appearing gray or light gray, with a somewhat poorer degree of surface smoothness;

② Water solubility. Ammonium phosphate nitrate, diammonium phosphate, and triple superphosphate are all soluble in water; granular calcium superphosphate is slightly soluble in water;

③ Burning. Ammonium phosphate and ammonium phosphate nitrate burn quickly on red charcoal, melt, and release ammonia gas; triple superphosphate and calcium superphosphate have no ammonia smell, and especially the granule shape of calcium superphosphate does not change at all.