Abstract: A pot culture experiment was conducted to examine the interference effectiveness of allelopathic rice Huakangcao 78 on weeds Echinochloa crusgalli L., Cyperus difformis L.,and Eclipta prostrata L. as affected by rice leaf age during transplanting, plant density, and soil surface water depth and its retaining days. The results showed that Huakangcao 78 could significantly reduce the dry weight of weeds compared with non-allelopathic rice Lemont. The control effectiveness of Huakangcao 78 onE. crusgalli L. was better when the weed was at 0～1.5 leaf age than at 1.5～2.4 leaf age, and that onC. difformis L. was better when the weed was at 0～0.3 leaf age than at 0.8～2.0 leaf age. The interactive effectiveness between rice leaf age during transplanting and plant density on weed control was better than that between the leaf age and soil surface water depth and its retaining days. To increase the rice leaf age during transplanting and plant density could significantly promote the control effectiveness of Huakangcao 78 on weeds.

Key words: Foliar leaching, NaCl stress, Growth, Mineral nutrition