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Critical period for weedy rice control in direct-seeded rice
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نویسنده
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Azmi M. ,Abdul Shukor J. ,Mohamad Najib M.Y.
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منبع
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journal of tropical agriculture and food science - 2007 - دوره : 35 - شماره : 2 - صفحه:333 -339
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چکیده
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On-station trials were conducted in mardi seberang perai in main season 2004/05 and off-season 2005 to determine the critical period of weedy rice control in direct-seeded rice. this period generally consisted of two discrete periods, a critical weed free period and a critical time of weed removal. the gompertz and logistic equations were fitted to data representing increasing durations of weed control and weed interference, respectively. in the main season 2004/05, only weedy rice was allowed to grow in association with direct-seeded rice. other weeds were controlled with selective herbicide applications. in the off- season 2005, mixed weeds including weedy rice were let to grow in association with direct-seeded crop. a period of weedy rice control lasting up to 53 das prevented a yield loss of more than 5% in main season 2004/05. however, weedy rice competition could cause 5% yield loss if it allowed to compete with direct-seeded crop until 16 das. therefore, the critical period for weedy rice control was from 16 to 53 das. in off-season 2005, to prevent a yield loss of more than 5%, a period of weed free lasting 60 das is required and weed competition could cause 5% yield loss if it allowed to compete with directseeded crop until 12 das. it indicates critical period for weed control under mixed weed infestation from 12 to 60 das under 5% yield loss.
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کلیدواژه
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critical period ,direct-seeded rice ,Gompertz and Logistic equations
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آدرس
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Malaysian Agriculture Research and Development Institute, Malaysia, Universiti Putra Malaysia, Faculty of Agriculture, Malaysia, Malaysian Agriculture Research and Development Institute, Malaysia
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پست الکترونیکی
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azmiman@mardi.my
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Authors
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