Weed management in dry-seeded rice (Oryza sativd) cultivated in the furrow-irrigated raised-bed planting system

摘要

Dry seeding of rice (Oryza saliva L.) in the furrow-irrigated raised-bed planting system (FIRBS) represents a major shift in the production practices for attaining optimal water productivity in the rice-wheat system in the Indo-Gangetic Plains of South Asia. Information on weed management in dry-seeded rice in the FIRBS is lacking. Two experiments were conducted for 2 years, with an objective of identifying appropriate, effective, and economical methods of managing: (1) broadleaf weeds only; and (2)a mixed population of both grass and broadleaf weeds in dry-seeded rice cultivated in the FIRBS. The major weeds associated with dry-seeded rice in the FIRBS during both years were Echinochloa crus-galli (L.) P. Beauv., Echinochloa colona (L.) Link, Dactyloctenium aegyptium (L.) Willd., LeptocMoa panicea (Retz.) Ohwl, Caesulia axillaris Roxb., Euphorbia hirta L., Lindernia sp., Commelina benghalensis L., Eclipta prostrata (L.) L., Trianthema portulacastmm L., and Portulaca oleracea L. Triclopyr at 500ga.i.ha~(-1), bensulfuron at 60g a.i. ha~(-1), ethoxysulfuron at 18g a.i. ha~(-1), and 2,4-D (ester) at 500g a.i. ha~(-1), all applied at 21 days after seeding (DAS), were equally effective in realizing higher rice grain yields by controlling broadleaf weeds. Among these, ethoxysulfuron at 18 g a.i. ha~(-1) was found to be least expensive but effective for controlling broadleaf weeds. Effective and economical herbicides identified for managing a mixed population of both grass and broadleaf weeds includedfenoxaprop-p-ethyl + ethoxysulfuron at 50 + 18 g a.i ha~(-1), applied at 21 DAS, and pendimethalin followed by (fb) chlorimuron + metsulfuron at 1000 fb 4g a.i. ha~(-1) applied at 3 fb 21 DAS.