Chemical Weeds Control in Fall Transplanting Onions in Southern Kerman Province

In order to control weeds in transplanting onions in southern Kerman province, an experiment was conducted based on randomized complete block design with 9 treatments and four replications during 2003-2004. The treatments included of Pendimethalin 33% in 4.5 L/ha (pre), Oxyfluorfen 24% in 2 L/ha (post), Oxadiazon 12% in 3 L/ha (pre and post), and Oxadiargyl WG and EC in 120 g/ha and 4 L/ha (post), respectively; plus weedy check. The results indicated that the application of herbicides decreased density and biomass of weeds and increased onion yield. Oxyfluorfen had maximum effect on reducing density and biomass of mallow (Malva parviflor L.), lambsquarter (Chenopodium album L.) and purple nutsedge (Cyperus rotundus L.). Barnyard grass (Echinochloa colonum L.) was successfully controlled by oxadiazon; lambsquarter was successfully controlled by all herbicides except Oxadiargyl; the highest onion yields belonged to Oxyfluorfen with 71.75 t/ha.