Weed infestation in direct seeded rice as influenced by nitrogen and weed management practices

Abstract

In order to study the effect of nitrogen and weed management practices on weed flora present in direct seeded rice an experiment was conducted during kharif season of 2015 and 2016 at Research Farm, Institute of Agricultural Sciences, Department of Agronomy, Banaras Hindu University, U.P. The experiment was laid out in split plot design in which four nitrogen and six weed management practices with three replications were adopted. The different treatments were allocated randomly in each replication. In the experimental field, the dominant weed species which generally effected the growth and yield of direct seeded rice were Echinochloa colona, Echinocloa crus galli and Cynodon dactylon among the grasses, Cyperus rotundus and Cyperus iria among the sedges and predominant broad leaved weeds included Caesulia axillaris and Eclipta alba. The minimum population of weeds was recorded with application of ¼ N at basal + ¼ at active tillering stage + ¼ N at panicle initiation stage + ¼ at heading stage (N4) which was statistically at par with 1/3 N at basal + 1/3 N at active tillering stage + 1/3 N at panicle initiation stage (N3) among nitrogen management practices. Among the weed management practices, two hand weedings at 20 and 40 DAS recorded lowest population of weeds which was followed by application of bispyribac at 25 g a.i. ha-1 + azimsulfuron at 17.5 g a.i. ha-1 + NIS (0.25 %) at 15-20 DAS (W5) in direct seeded rice at 60 DAS and at harvest stage.