Improving wheat productivity through integrated management of Avena ludoviciana

In Australia, wheat planting is preferred in June compared with May to kill early cohorts of weeds before planting, particularly in fields with a history of high weed infestation. However, wheat grain yield is often reduced for June planting. This study aimed to investigate the integrated effect of planting dates (May 7, i.e., early-planted, and June 7, i.e., late-planted), seeding rates (100 and 200 seeds m(-2)), and weed control treatments (nontreated control, pyroxasulfone 100 g a.i. ha(-1), triallate 800 g a.i. ha(-1), trifluralin 600 g a.i. ha(-1), and prosulfocarb 2000 g a.i. ha(-1) + S-metolachlor 300 g a.i. ha(-1)) on Avena ludoviciana (Durieu) control and wheat yield. For early-planted wheat, the pyroxasulfone-treated plots had a higher yield (5.5 Mg ha(-1)) at a low seeding rate compared with a high seeding rate (4.7 Mg ha(-1)). Pyroxasulfone and triallate treatments in early-planted wheat using a low seeding rate produced a higher yield than each treatment of late-planted wheat. In late-planted wheat, varied seeding rates did not influence grain yield, irrespective of weed control treatments. Pyroxasulfone and triallate treatments in early-planted wheat at a low seeding rate gave similar yields, and yield levels in these treatments were higher than trifluralin and prosulfocarb + S-metolachlor treatments. A high seeding rate in early-planted wheat resulted in an increased grain yield by 42%, 27%, and 28% in nontreated, trifluralin, and prosulfocarb + S-metolachlor, respectively, compared with a low seeding rate. Weed biomass and weed seed production were lower in late-planted wheat than in early-planted wheat. Pyroxasulfone- and triallate-treated plots accrued lower weed biomass and weed seed production than the nontreated plots. Averaged over weed control treatments, weed seed production was highest (2700 seeds m(-2)) in the early crop planted at a low seeding rate, which was reduced by 42% with late planting using a similar seeding rate. Averaged over weed control treatments, a high seeding rate in early- and late-planted crops reduced weed seed production by 68% and 48%, respectively, compared with a low seeding rate. These results suggest that pyroxasulfone in early-planted wheat can control A. ludoviciana effectively, limit weed seed production similar to late-planted wheat, and prove a profitable option due to improved productivity compared with late-planted wheat.