Abstract: The potted experiment showed that,the unknown substances in hibit ing the tuber growth of Dihuang (Rehmannia glutinosa Libosch.) were from root exudates,leaves and tubers of Di Huang.The root exudates significantly inhibited the tuber expand,and secondly the leaves did.They were the major causes of continuous cropping barrier in d-ihuang.Steamsterilizing the old soil or adding active carbon and ascorbic acid can effect ively overcome the continuous cropping barrier.But the field effect should be further studied.

Key words: Dihuang, Continuous cropping barrier, Overcome

CLC Number: 

• S567