Influence of nitrogen and weed management practices on weed dynamics in direct seeded wet rice.

摘要

A study was conducted in India during the kharif seasons of 2003 and 2004 to determine the effects of nitrogen and weed management practices on weed dynamics and directly sown wet rice (cv. Pusa Basmati 1). Treatments comprised: four nitrogen schedules (0:25:40:35, 25:0:40:35, 50:0:25:25 and 0:40:30:30% N at 0, 25, 35 and 60 days after sowing; DAS) and five weed management practices (hand weeding at 20 DAS at 20 DAS, hand weeding at 20 and 35 DAS, anilofos at 0.4 kg a.i./ha, anilofos at 0.4 kg a.i./ha + 2,4-D at 0.5 kg a.i./ha, and a weedy control). The results showed that the weed infestation and dry matter accumulation at harvest were significantly lower upon treatment with 0:25:40:35% N at 0, 25, 35 and 60 DAS, respectively, compared to other N schedule. Echinochloa colona, Eclipta alba and Eleusine indica were among the most dominant weed species under 0:25:40:35% N at 0, 20, 35 and 60 DAS, respectively. Cyperus rotundus and Borreria diffusa were the most dominant weed species under 0:40:30:30% N and 25:0:40:35% N at 0, 20, 35 and 60 DAS. Among the weed management practices, hand weeding at 20 and 35 DAS showed significantly lower weed population and dry matter production of weeds at harvest.