Zinc is an indispensable trace element for crop growth. Zinc deficiency can cause dwarfing of plants, short internodes, inhibition of leaf expansion and elongation, and appearance of leaflets with twisted and wrinkled edges. Alzheimer's corn seedlings and rice seedlings are caused by zinc deficiency. There are four methods for preventing and treating zinc deficiency in crops: 1. Seed dressing: Dissolve zinc sulfate in a small amount of water and mix well with the seeds. Allow to dry after sowing. 2. Soaking: soaking with zinc sulfate solution, corn can be soaked for 6~8 hours, the solution concentration is 0.02%~0.05%; rice can be soaked for 12 hours, the solution concentration is 0.1%. 3. Foliar spraying: 0.1% zinc sulfate can be sprayed immediately after the occurrence of zinc deficiency symptoms in the early stage of crop growth, and sprayed once every 7-10 days. 4. Soil application: Mix with other fertilizers to make basal fertilizer. The dosage is 1~3 kg/mu and pay attention to uniform application.