Compound fertilizer can be divided into potassium sulfate type and potassium chloride type. Most fruits and vegetables belong to chlorine-free crops, so potassium sulfate compound fertilizer should be used, and potassium chloride compound fertilizer can be used for field crops such as corn and wheat. Potassium chloride is much cheaper than potassium sulfate, so I suggest using potassium chloride compound fertilizer as long as it is not a chlorine-free crop, which can save costs and have the same fertilizer efficiency. The so-called high chlorine compound fertilizer should be a compound fertilizer containing both potassium chloride and ammonium chloride. Known in the industry as double chlorine compound fertilizer. It has a high chlorine content, so the price should be lower. As long as it is not a chlorine-free crop, it can be applied without influence, as long as the content of nitrogen, phosphorus and potassium reaches the standard.