There are many kinds of chemical fertilizers, including nitrogen fertilizer (including ammonium bicarbonate, urea, ammonium nitrate, etc.), phosphate fertilizer (including superphosphate, superphosphate, calcium magnesium phosphate, phosphate nitrate, etc.), potassium fertilizer (potassium chloride, potassium sulfate), compound fertilizer (including monoammonium phosphate, diammonium phosphate, potassium nitrate, etc.) and compound fertilizer (a mixture of the above fertilizers or organic fertilizer). Among them, nitrogen fertilizer is the easiest to volatilize: after ammonium bicarbonate is unpacked, it will volatilize about 30% after being placed at 25 degrees for 7 days, and it will basically evaporate after being exposed to the sun for one day in summer; Urea and ammonium nitrate are also unstable. When opened, the package will volatilize about 50% at 35 degrees 10 day, and it is easy to absorb moisture and agglomerate. Other fertilizers are not volatile, but they are also easy to agglomerate or absorb moisture. Although the old chemical fertilizer and the new chemical fertilizer have basically the same fertilizer efficiency, they become hard chunks after absorbing moisture and caking, which is very inconvenient to use, unless they are broken by a machine again, which is too troublesome!