STUDY OF WEED MANAGEMENT OPTIONS, WEED DYNAMICS AND CROP YIELD IN IRRIGATED HYBRID MAIZE

Field experiments were conducted at Maize Research Station, Vagarai, Tamilnadu during kharif season of years 2015, 2016 and 2017 to assess the performance of herbicide molecules on weed dynamics and grain yield of maize under irrigated field condition. The herbicide molecules of atrazine, pendimethalin, halosuluron and tembotrion were tried at different doses, combinations and time. The combinations were fixed as Atrazine @ 1500 g a.i./ha PE, Atrazine (750 g a.i./ha) + Pendimethalin (750 ml a.i./ha) PE, Atrazine (750 g a.i./ha) + 2,4-D Amine (75%) at 25 DAS as PoE, Halosulfuron 60 g a.i./ha at 25 DAS, Atrazine @ 1500 g a.i./ha PE fb Halosulfuron 60 g a.i./ha 25 DAS, Tembotrione 120 g a.i./ha PoE at 25 DAS, Pendimethalin (1000 ml a.i./ha) PE fb Atrazine (750 g a.i./ha) + 2,4-D Amine (75%) at 25 DAS, Atrazine @ 1500 kg a.i./ha PE fb Tembotrione 120 g a.i./ha) PoE at 25 DAS, Atrazine @ 250 g a.i./ha + One hand weeding at 30 – 35 DAS and Atrazine @ 250 g a.i./ha + 2,4 D @ 1000 g/ha at 20-25 DAS. These combinations and their effect were compared with weedy check and weed free check. These trials were laid out in the statistical model RBD and replicated thrice. The result of the experiment revealed that lesser number of broad leaved weeds were recorded under application of atrazine @ 1500 g a.i./ha PE fb tembotrione @ 120 g a.i./ha PoE at 25 DAS at 50 DAS and at harvest. Grass weed population was significantly lesser under atrazine @ 250 g/ha + One Hand weeding done at 30-35 DAS and application of atrazine @ 750 g a.i./ha + pendimethalin @ 750 ml a.i./ha as pre-emergence at harvest stage. Weed control efficiency was higher under pre-emergence application of pendimethalin @ 1000 ml a.i./ha fb atrazine @ 750 g a.i./ha + 2,4 D amine salt. Higher grain yield (9768 kg/ha) was recorded in atrazine (1500 g a.i./ha) as pre-emergence herbicide, which was followed by halosulfuron @ 60 g/ha at 25 DAS as PoE at 50 DAS, which was on par with weed free treatment and followed by application of pendimethalin @ 1000 ml a.i./ha as PE fb atrazine @ 750 g a.i./ha + 2,4 D amine (75%) at 25 DAS as PoE alsofollwed by application of atrazine @ 250 g a.i./ha + One hand weeding at 30-35 DAS and application of tembotrione @ 120 g a.i./ha as PoE at 25 DAS.