The main degradation factors of azadirachtin A was water-holding in the sterilized soil, but in the non-sterilized soil were water-holding and microorganism, and their DT50 were 22.21 and 17.54d.

• 印楝素A在灭菌土中的降解主要受土壤含水量的影响，而在未灭菌土中主要受土壤含水量和微生物的影响，降解半衰期分别为22.；21、17