Efficacy of Herbicides on Weed Dynamics and Weed Control Efficiency and its Effect on Productivity and Economics of Kharif Maize

A range of herbicides was tested in the kharif season for three consecutive years (2015-2017) to
find out the best broad spectrum pre and post-emergence herbicide for maize cultivation in
Peninsular India. The result revealed that application of Atrazine (0.75 kg a.i./ha) + 2,4-D
Amine (0.4 kg a.i./ha) at 25 DAS as post-emergence (T9); Atrazine @ 1.5 kg a.i./ha as
preemergence followed by Tembotrione @ 120g a.i./ha as post-emergence at 25 DAS (T10);
and Atrazine (0.75 kg a.i./ha) + Pendimethalin (0.75 kg a.i./ha) as preemergence (T4)
effectively controlled the narrow and broad-leaved weeds throughout the cropping cycle. Post-
emergence application of Halosulfuron @ 90 g/ha at 25 DAS was found highly effective in
reducing sedge infestation in the maize crop. Unweeded plots registered 31.3 % yield penalty
over weed-free plots. While chemical weed management employing various herbicides
registered a 10-40% yield improvement over the weedy check. Among the various herbicides,
T9, T10, and T4 recorded at par maize grain and straw yields, growth, and yield parameters
with weed-free plots and showed the lowest yield penalty (weed index) caused by weeds over
weed-free plots. Based on the findings, it may be concluded that application of Atrazine (0.75
kg a.i/ha) + Pendimethalin (0.75 kg a.i/ha) (T4); Atrazine (0.75 kg a.i./ha) + 2,4-D Amine (0.4
kg a.i./ha) at 25days after sowing(DAS) as post-emergence (T5); Pendimethalin (1 kg a.i/ha) as
pre-emergence followed by Atrazine (0.75 kg a.i/ha) + 2,4-D Amine (0.4 kg a.i/ha) at 25 DAS
as post-emergence (T9) ; and Atrazine (1.5 kg a.i/ha1) as pre-emergence followed by
Tembotrione (120 g a.i/ha) at 25 DAS (T10) can be used to effectively reduce weed infestation
and to get higher grain yield and net returns of maize in Peninsular India.