Potassium nitrate is a neutral potassium fertilizer containing nitrogen and potassium. It contains 13.5% nitrate nitrogen and 46% potassium, which is superior to potassium sulfate in water solubility and fertilizer absorption and utilization rate. Moreover, potassium nitrate is not easy to cause soil acidification, but because of the role of potassium fertilizer containing nitrate. One is to promote the activation of enzymes. The second is to increase photosynthesis. The third is to promote the metabolism of sugar. The fourth is to promote the synthesis of protein. The fifth is to enhance the resilience of crops. Sixth, improve output and quality.

Potassium sulfate. Potassium sulfate is a potassium fertilizer based on sulfate radical, which contains no chlorine or only low chlorine, and is basically the most widely used elemental potassium fertilizer. 70% of potassium sulfate in China is converted from potassium chloride. So the price of potassium sulfate is relatively high. In the early stage, farmers used a lot of manure and organic fertilizer as base fertilizer, which led to excessive nitrogen fertilizer, too fast crop growth, tender stems, easy virtual length, easy invasion of bacteria, pulp necrosis, stem rot, falling flowers and fruits, downy mildew,

Potassium sulfate contains more than 48% potassium, which can be used as base fertilizer, topdressing, seed fertilizer and foliar fertilizer. If potassium sulfate is used in acidic soil for a long time, it must be used in combination with alkaline fertilizers, such as calcium magnesium phosphate fertilizer and phosphate rock powder, to prevent soil hardening and acidification. The content of effective components of potassium chloride is generally 50-60%, which belongs to physiological acid fertilizer and can be used as base fertilizer, topdressing and topdressing outside roots. The application should be avoided in coastal areas, and varieties susceptible to manganese damage (apple scab) such as Fuji and Hongxing should be banned.

The main function of nitrogen fertilizer is to make trees flourish, increase chlorophyll and strengthen vegetative growth. If there is too much nitrogen fertilizer, the plant tissues will be soft, the stems and leaves will be white and long, and diseases and insect pests will easily occur, which will lead to the decline of cold tolerance. Plants lacking nitrogen fertilizer will be thinner. Nitrogen fertilizer is the most absorbed fertilizer in the process of crop growth, and it is also an essential fertilizer for crops. The application of nitrogen fertilizer mainly plays the role of raising seedlings, which can help crops to carry out photosynthesis and produce chlorophyll. Generally speaking, if the crops are short and the leaves are yellow.