Effect of Tank Mixture Herbicides on Phytotoxicity, Soil Dehydrogenase Activity and Nutrient Uptake by Weeds in Maize (Zea mays L.)

A field experiment was conducted under rainfed conditions during kharif 2013 at Agricultural College farm, University of Agricultural Sciences, Dharwad, to study the effect of different doses of herbicides in tank mixture on phytotoxicity, dehydrogenase activity, nutrient uptake and growth and yield components of maize. Treatments i.e. atrazine @ 0.625 kg ha ¹ + oxyfluorfen@ 0.10 kg ha¹ fb 2,4-D @ 0.5 kgha¹ (T₅) and alachlor @ 0.75 kg ha¹ + oxyfluorfen @ 0.10 kg ha¹ fb 2,4-D @ 0.5 kg ha¹ (T₈) has recorded phytotoxicity on crops at 7, 14 and 21 days after spraying of pre - emergence herbicides and also reduces soil microbial load in the soil due to higher concentration of herbicides. Whereas, pre -emergence application of atrazine @ 0.625 kg ha¹ + pendimethalin @ 0.5 kg ha ¹ fb 2,4-D @ 0.5 kg ha ¹ - (T_-4) resulted in higher dehydrogenase activity, nutrient uptake and grain yield due to effective control of weeds in initial stage of the crop growth.