Fertilizers containing toxic effects are mainly the most used urea in crop production. In the production of crops, urea often produces a small amount of biuret. The content of this substance is more than 2%, and it will produce poison to the seeds and seedlings.
One type of fertilizer containing harmful ions is potassium chloride and ammonium chloride. Such fertilizers contain chloride ions, and they produce water-soluble chlorides after application, which is detrimental to seed germination and seedling growth. The other class is ammonium nitrate, potassium nitrate. Because it contains nitrate ions, it has a great influence on the germination of seeds.
Corrosive fertilizers such as ammonium bicarbonate and superphosphate. If such fertilizer is used as a seed fertilizer for cultivation of Chinese medicinal materials, it will cause serious damage to the seed germination and seedlings. If the soil quality is poor, be sure to apply this kind of fertilizer. Apply it to the ditch or the bottom layer, cover it with a layer of fine soil, and sow the seeds of the herbs. Mix the superphosphate and the earth fertilizer and apply it evenly. When planting Chinese herbal medicines, such fertilizers should be avoided from direct contact with seedlings of medicinal seeds.