Attention should be paid to reducing the re-infection of diseases and insect pests after soil disinfection.

After disinfection with calcium cyanide, methyl bromide and methylene bromide in the greenhouse planted for many years, it can kill most of the pathogens in the soil of the greenhouse and reduce the occurrence of soil-borne diseases, especially root-knot nematodes. However, many vegetable farmers only pay attention to how to kill pathogens, but ignore to prevent the re-introduction of pathogens, leading to the disease of vegetables, greatly weakening the effect of soil disinfection, so many vegetable farmers think that soil disinfectants are useless or fake.

In order to control soil-borne diseases, soil disinfection is the basis, but to avoid the occurrence of diseases and prevent the re-introduction of pathogens can not be ignored. First of all, when disinfecting, the tools should be disinfected in the shed at the same time; secondly, the clothes and shoes working in the greenhouse had better be special, and they should be replaced when they leave the shed; the soilless matrix should be adopted for raising seedlings, and the soil for raising seedlings must be disinfected to prevent or reduce the re-invasion of foreign germs and nematodes. After soil disinfection, all the microorganisms in the soil are killed. In order to improve the vitality of soil beneficial microorganisms, biological bacterial fertilizer can be applied, such as actinomycetes (Qingdao DND biological fertilizer) and so on. The application of biological bacterial fertilizer should be separated from chemical fertilizer, chemical fertilizer can be used in advance, and then biological bacterial fertilizer, ditch application or hole application should be used when planting.

In addition, after soil disinfection, the plant growth is particularly prosperous, especially calcium cyanide also contains higher nitrogen, so the amount of nitrogen fertilizer should be reduced by about 1 to 3 after soil disinfection. Otherwise, it is easy to cause the seedlings to grow, which is not conducive to the cultivation of strong trees and increase the yield.