Portulaca oleracea(common purslane) is a summer annual weed with wide geographic distribution and is problematic in many crops worldwide. Field experiments were conducted to determine the effects of different management practices on P. oleraceaemergence in soyabean fields. Two tillage systems [conventional tillage (CT) and no-till (NT)], three soyabean seeding rates (SR) (200 000, 300 000 and 400 000 seeds ha 1 ) and three imazethapyr doses (0, 50, and 100 g a.i. ha 1 applied pre-emergence) were considered as experimental factors.Portulaca oleraceaemergence was affected by management practices including tillage system, soyabean SR and imazethapyr dose. Conventional tillage required a thermal time (TT) of 195.95 and 221.30 d°C to reach 50% emergence in 2016 and 2017, respectively, while for NT, the respective TT requirements were 182.34 and 203.32 d°C. On increasing soyabean SR from 200 000 to 400 000 seeds ha 1 , the TT requirements for 50% emergence (T50 )ofP. oleraceaalso increased. TheT50 at the herbicide dose of 100 g a.i. ha 1 was 193.05 and 220.67 d°C in 2016 and 2017, respectively, while for the non-herbicide treatment, the respective TT requirements were 165.98 and 202.94 d°C. From an integrated weed management perspective, a combination of CT with a SR of 400 000 seeds ha 1 and a 100 g a.i. ha 1 imazethapyr dose not only resulted in the lowestP. oleraceaseedling density m 2 but also caused the longest delay in the time to reach the T50. Findings from our study may facilitate the development of effectiveP. oleracea management strategies.
کلید واژگان :cumulative emergence, conventional tillage, no-till, seeding rate, imazethapyr
ارزش ریالی : 600000 ریال
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