Abstract:The allelopathy of the straws of five oilseed rape varieties and seven wheat varieties was investigated by using petri dish bioassay on the predominant weeds in direct-seeding rice field, such as Leptochloa chinensis, Echinochloa crusgall and Eclipta prostrate. Subsequently, the control effects of screened varieties were confirmed under simulated field conditions in green house, as well as its safety to rice. The results showed that two oilseed rape varieties, Shilifeng and Huiyou 50, exhibited great inhibition to all the three species weeds mentioned above, especially on the seed germination of L.chinensis with percentage inhibition of seed germination of 65.33% and 55.33%, respectively. Also they could inhibit the root growth of weeds, of which the response index (RI) could reach to -0.82 and -0.85, respectively. It was observed that the aqueous extraction from residues of Shilifeng could promote weed growth at low concentrations and inhibit the growth at high concentrations. In greenhouse experiment, the straws of Shilifeng could effectively control weeds, of which the response index could reach to -0.91, -0.64, -0.67, respectively, and be safe to rice growth at the rate of 25kg/m3. The experiments showed that superficial incorporation with the straws of Shilifeng could be adopted as an effective strategy in integrated weed management.