This Study was conducted to evaluate the effect of fresh and dry parts of Soybean (Glycine max) on germination and growth of Secale cereal seedlings in order to determine the inhibitory effect of soybean and effect of drying on the phytotoxic activity of this plant. Results showed that the germination percentage,germination rate, seedling growth and fresh and dry matter production of Secale cereal were retarded by all the four different aqueous extracts applied. The degree of retardatory effects of the aqueous extracts were found to follow this order: dry shoot aqueous extract (DSE) > dry root aqueous extract (DRE) > fresh shoot aqueous extract (FSE)> fresh root aqueous extract (FRE). There was a significantly higher phytotoxic potency at p<0.05 in the dry tissue aqueous extract compared with the fresh tissue aqueous extract. Allelopathy appears to be one mechanism for competition among soybeans and weeds. Soybean possessing the ability to chemically inhibit competing weed growth would be a great benefit to the soybean producer.
