A disease that seriously harms broad beans often occurs in broad bean production areas. It is mainly characterized by dwarfing, cluster tops and leaf dieback. People call it "dwarfing disease", "burning branches", etc. People who get this disease , the light ones are reduced production, the serious ones are no harvests. This disease is a physiological potassium deficiency caused by the inability of the potassium supply level in the soil to meet the growth and development needs of broad beans and the imbalance of the nitrogen and potassium ratio in the soil. It is called broad bean potassium deficiency leaf blight. This disease begins with yellowing of the edges of the middle and upper leaves of the plant, and gradually dies with a burning appearance.

The dead parts spread and expand, and the stems gradually die, and in severe cases, the entire plant dies. There are two types of this disease. One is the "dwarf type", which usually develops in mid-to-late November or early December. The plants are dwarfed and the leaves die. Without potassium fertilizer, most pods cannot be formed and the harvest is very small. The second type is that the plants are not dwarfed. , only the edges of the leaves are dead, and they can generally form pods, but the yield is very low. The key to preventing and controlling "potassium deficiency leaf blight of broad beans" is to apply potassium fertilizer to the soil to meet the potassium requirements for the growth and development of broad beans and achieve a coordinated supply ratio of nitrogen and potassium. The amount of application, based on potassium sulfate, is 10-15 kilograms per acre, which is more economical and effective. The best effect is to apply Boshemeh potassium fertilizer as seed fertilizer or three or four leaves before the seedling stage. The application method, such as using potassium sulfate mixed with water and pouring it on the roots, has the best effect. Or after planting beans, apply potassium sulfate about 1.5 cm away from the seeds; stove ash, grass ash, farmyard manure and straw are potassium fertilizer resources available throughout the countryside. In areas where chemical potassium fertilizers are lacking, stove ash can be used , grass ash, etc., the disease prevention effect after application can be more than 80%