Atrazine, Herbicide combinations, Maize, Pendimethalin, Weeds

Twelve treatments involving tank-mix combinations of atrazine and pendimethalin as pre-emergence followed by (fb) post emergence application of 2,4-D and metsulfuron methyl along with hand weeding twice (20 and 40 DAS) and untreated check were tested in maize during 2009 and 2010 at Palampur. Echinochloa colona, Panicum dichotomiflorum, Cyperus iria, Commelina benghalensis, Ageratum conyzoides, Digitaria sanguinalis and Polygonum alatum were the dominant weeds. Pendimethalin 1.50 kg/ha, atrazine fb atrazine 0.75 kg/ha, atrazine 0.75/1.0 +  pendimethalin 0.75/0.50 fb metsulfuron methyl 4 g/ha effectively controlled Echinochloa colona. Atrazine fb atrazine brought about significant reduction in the count of  Panicum dichotomiflorum up to 60 DAS. Pendimethalin fb atrazine, atrazine 1.0 + pendimethalin 0.50 fb 2, 4-D 0.75 kg/ha and hand weeding twice effectively reduced the population of Commelina up to 60 DAS. Pendimethalin/atrazine fb atrazine and atrazine + pendimethalin fb 2,4-D/metsulfuron-methyl controlled  Ageratum conyzoides up to 60 DAS. Pendimethalin/atrazine fb atrazine, atrazine + pendimethalin fb metsulfuron-methyl/2, 4-D and pendimethalin significantly reduced total weed dry weight. Atrazine 1.0 + pendimethalin 0.50 kg/ha (post) and atrazine 0.75 + pendimethalin 0.75 kg/ha fb 2, 4-D gave significantly higher grain yield and net returns. Weeds reduced maize grain yield by 50.3%.