Influence of Integrated Weed Management Practices on Dynamics and Weed Control Efficiency in Dry Direct Seeded Rice

Field experiment under dry direct seeded rice(O ryza sativa L.) was conducted during rainy season of 2010 and 2011 at Regional Agriculture Research Station (RARS), Parwanipur, Bara to develop appropriate weed management practices for dry direct- seeded rice. The trial was laid-out in randomized complete block design (RCBD) and replicated thrice. Observations were taken on weed, plant growth and yield attributing, yield, and socio-economic parameters. The weed density, dry weed weight and weed control efficiency resulted significantly different as influenced by integrated weed management practices. Low weed population density, low weed index and highest weed control efficiency resulted by pendimethalin followed by 2, 4- D followed by one hand weeding were at par with weed free check. Highest yield resulted from weed free plot followed by pendimethalin followed by two hand weeding and pendimethalin followed by 2, 4- D followed by one hand weeding. However, the net return per unit investment resulted highest in pendimethalin followed by 2, 4- D followed by one hand weeding. This proved that amid increasing wage rate and labour scarcity integrated weed management through pendimethalin 30 EC (Stomp) @1 kg a. i. /ha as pre- emergence herbicide application followed by 2, 4- D sodium salt 80 WP @ 0.5 kg a. i. /ha followed by one hand weeding or stale seed bed followed by pendimethalin 30 EC (Stomp) @1 kg a. i. /ha followed by bispyribac (Nominee gold) @25 g a. i. /ha 10% @200 ml/ha at 20 days of seeding resulted best alternative for manual hand weeding practices giving higher net return per unit investment. DOI: http://dx.doi.org/10.3126/njst.v14i2.10413 ？ Nepal Journal of Science and Technology Vol. 14, No. 2 (2013) 33-42