Crop establishment of rice through wet-seeding and its weed management practices - An emerging issue - A review

Direct wet seeding offers the advantage of faster and easier planting, reduced labour and less drudgery, 7–10 days earlier crop maturity, more efficient water use and higher tolerance to water deficit, less methane emission, and often higher profit in areas with assured water supply. This method of seeding in the past has received relatively less attention than transplanting. Sowing of sprouted rice seed or wet-seeded rice in puddled soil though becoming increasingly important as a method of crop establishment under lowland rice is beset with weed problems, particularly grassy weeds besides other management practices. Weeds emerge at about the same time that the rice seeds germinate, and therefore the yield losses caused by weeds will become greater with the trend towards wet seeding. Effective weed control is one of the key issue and major requirements to ensure a successful wet-seeded rice crop. Furthermore, varieties must be improved for early seeding vigor, weed competitiveness, submergence tolerance to survive untimely rainfall during stand establishment and drought tolerance to survive dry conditions during germination and later growth stages, and for lodging resistance at maturity. An attempt has been made in this paper to review and discuss the wet seeding rice vis-à-vis weed management techniques that can be used to develop an improved integrated weed control technology for wet-seeded rice. Besides this other management constraints to ensure optimum conditions for seeding have also been reviewed.