1. Due to the poor ventilation and light transmission conditions of the protection area, high temperature and high humidity, fertilizers are not easy to produce. 2. The main measures for the prevention of fertilizer damage in greenhouses are the following seven: First, control the amount of fertilizer, and the mid-range level is appropriate. The second is to master the principle of applying thin fertilizer. The amount of chemical fertilizer should not be too much, ammonium sulfate is less than 15 kg/mu, urea is less than 8 kg/mu, and superphosphate is less than 25 kg/mu. The third is to increase organic fertilizer and improve soil fertility, but should not use unripe organic fertilizer. The fourth is to advocate full-scale deep application or ditch application of earth, and it is not appropriate to spread on the surface. Fifth, NPK and trace element fertilizers should be applied together. Sixth, it uses precipitation and irrigation to wash salt in the summer. Seventh, deep plowing of soil or addition of soil, or rotation of greenhouses to reduce the surface salt.