Wheat seeding time, seeding rate and trifluralin application affect the control of wild oat (Avena fatua).

Abstract

Field experiments were conducted in Tsukuba, Ibaraki, in 2000 and 2001, to determine the effects of seeding time and trifluralin application on suppression of wild oat (Avena fatua, which causes serious problems in winter cereal production) and winter wheat growth. Wild oat emerged mainly in late November to early December in both years. Delayed seeding reduced wild oat density; a seeding date past late November was estimated to suppress wild oat seed set lower than the initial density. Trifluralin emulsion applied at 1.34 kg/ha, highest recommended rate, reduced wild oat plants, panicles and spikelets to 70% and 30% of controls, with variation between years. The effect of trifluralin application on wild oat suppression was roughly equivalent to one week delayed seeding, indicating that late November seeding with trifluralin correspond to early December seeding without trifluralin. Seeding time affect wheat growth, delayed seeding time caused yield reduction in the 2000 experiment, when weather conditions were cold, even though seeding rates were increased. These data indicate that delayed seeding is effective for wild oat management in infested fields and can replace the need for trifluralin application.