Dev Kumar Saphi, Dil Raj Yadav
Abstract: Weeds are the major problem in dry direct seeded conditions competing with the different resources provided to the crop. Hence, field experiments were conducted during rainy seasons of 2013 and 2014 at the experimental field of Rice Research Program, Hardinath, Dhanusha to identify the effective herbicides for control of broad spectrum of weeds in dry direct seeded rice. The experiment was laid out in a randomized complete block design with four replications. Four weed control methods (pendimethalin @ 1000 g a.i./ha as pre-emergence followed by 2, 4-D @ 1000 g a.i./ha as post-emergence, pendimethalin @ 1000 g a.i./ha as pre-emergence followed by penoxsulam @ 22.5 g a.i./ha as post-emergence, pyrazosulfuron ethyl @ 20 g a.i./ha as pre-emergence followed by 2, 4-D @ 1000 g a.i./ha as post-emergence, pyrazosulfuron ethyl @ 20 g a.i./ha as pre-emergence followed by Bispyribac sodium @ 25 g a.i/ha + azimsulfuron @ 17.5 g a.i./ha and weedy check as control) were evaluated. The statistical analysis showed that the effect of weed control methods on yield and yield attributing parameters of the tested rice varieties was significant. Of the tested herbicides, the highest grain yield of 4.1 t/ha was recorded in pyrazosulfuron fb bispyribac sodium + azimsulfuron. This treatment was found to control broad spectrum of weeds and reduced the weed biomass by 92 %.
Keywords: Dry direct seeded, herbicides, weed biomass