Potassium chloride is the protagonist of potassium fertilizer. Potassium sulphate must be used for specific chlorine-repellent crops such as tobacco, and potassium chloride should be used when soybeans, onions, garlic, rape and berry-like sulfur crops are available when conditions permit. Because most crops use potassium chloride is not harmful, especially in the rain and irrigation conditions. Potassium chloride is cheaper than potassium sulfate and its potassium content is high. The blind promotion of potassium sulfate and sulfur-based compound fertilizer will not only increase the burden on farmers, but also the residual sulfate in the soil will also acidify the soil, or combine with calcium ions to form something like gypsum, which will make the soil compact.