Effect of seeding methods, in situ incorporation of Dhaicha (Sesbania aculeata Poir) and application time of pretilachlor plus on weed growth and yield of wet seeded rice (Oryza sativa L.)

摘要

Direct seeding constitutes both wet and dry seeding and it does away with the need for seedlings, nursery preparation, uprooting of seedlings and transplanting (Pandey, 1995). Availability of drum seeders makes wet seeding more pragmatic. However, wet seeding is beset with poor and uneven establishment and inadequate weed control (Tamil Selvan and Budhar, 2001). Rice farmers in the tropics practise wet seeding by broadcasting or line seeding of germinated seeds on the puddle soil surface where seeds are more often splashed by heavy rain, destroyed by birds and rodents. Weeds emerge at about same time as the rice seedlings do and yield losses caused by weeds are greater in wet seeding. During early establishment, weeds make 20 to 30 percent of their growth, while crop makes only 2 to 3 percent of its growth (Moody, 1990). Intercropping and herbicides preferably pre-emergence herbicides are vital tools for effective and cost-efficient weed control in wet seeded rice. Few studies have been made on intercropped dhaincha and its incorporation on soil fertility and weeds under wet seeded rice.