1. First of all, you need to "check" the outer packaging, regardless of whether the outer packaging is marked with trademark, license number, registration number, nutritional ingredients, factory name and address.

2. When burning again, the fertilizer will burn ammonia on the iron plate. This shows that nitrogen is slowly melting, and the residue after burning for a period of time is a high-quality fertilizer.

3. Then dissolve it in water, put the fertilizer into a water bottle, add a proper amount of water, and then shake it violently. High-quality fertilizers are particularly soluble in water, most of them are soluble, and even a small amount of residues are particularly fine. The fertilizer is poor and insoluble in water, and the residue is rough and hard.

4, feel, texture, fertilizer general quality is not difficult, even difficult to fall behind and relatively hard. Inferior fertilizer is easy to grind, and it is rich in powder.

5. It smells that chemical fertilizer is a chemical product, and the raw materials are like newly bought plastic sheets, which need to smell pungent smell.