Abstract
A field experiment were conducted for two years at Agricultural Research Station, Bhavanisagar of Tamil Nadu Agricultural University, during kharif season of 2009 and 2010 to evaluate the new formulation of oxyfluorfen (23.5% EC) on weed control in onion. Weeds constitute one of the biggest problems in agriculture that not only reduce the yield and quality of onion but also utilize essential nutrients. Hence, weed control is essential for increasing onion production. Based on two years field experimentation, it was found that pre-emergence application of oxyfluorfen (23.5% EC) at400 g.ha-1 gave significantly lower total weed density, weed dry weight and higher weed control efficiency at all the intervals. Application of new formulation of oxyfluorfen (23.5% EC) at200 g.ha-1 as pre-emergence herbicide can keep the weed density and dry weight below the economic threshold level and increase the bulb weight (42.56 and43.87 g) and yield (15940 and15610 kg.ha-1) in onion. Unweeded control accounted for lower bulb yield which inturn reflected through higher weed index of 60.6 and 56.1 per cent, respectively during both the years, due to heavy competition of weeds for nutrients, space and light.
Highlights
Onion (Allium cepa var. aggregatum L.) belonging to the family Alliaceae is one of the important bulbous vegetable crop of economic importance and widely cultivated all over the world, with particular distribution in the Asian continent and in Europe
Treatments consisted of pre-emergence application of already registered oxyfluorfen at 200 g·ha−1, new formulation of oxyfluorfen (23.5% EC) at 150, 200, 250, 300 and 400 g·ha−1, pendimethalin 0.75 kg·ha−1 + Hand weeding on 45 DAS, pendimethalin 0.75 kg·ha−1 + Rotary weeding on 45 DAS, Hand weeding twice on 25 and 45 DAS and unweeded check
Throughout the experimental period, weed control efficiency was higher with pre-emergence application of oxyfluorfen at 400 g·ha−1 followed by oxyfluorfen spray at 250 and 300 g·ha−1 owing to the fact that it registered lesser weed density and weed dry weight [16]
Summary
Onion (Allium cepa var. aggregatum L.) belonging to the family Alliaceae is one of the important bulbous vegetable crop of economic importance and widely cultivated all over the world, with particular distribution in the Asian continent and in Europe. Due to its poor competitive ability with its slow initial growth and lack of adequate foliage makes onion weak against weeds. Their cylindrical upright leaves do not shade the soil to block weed growth. Under chemical method of weed management, the rotation of herbicides is more essential to prevent the weeds to develop resistance to herbicides. Beneath these backdrops, newer formulation of herbicides is coming in the market with wide spectrum of weed control efficiency. The new herbicide formulations are to be evaluated for their bioefficacy of controlling wide range of weed flora, better crop growth and yield of onion. In view of the above facts, an experiment on “Efficiency evaluation of new formulation of oxyfluorfen (23.5% EC) on weed control in onion and their residual effect on succeeding crops” was formulated with the following objectives: 1) To evaluate the bio-efficacy of new formulation of oxyfluorfen (23.5% EC) on weed control in onion; 2) To examine phytotoxic effects of oxfluorfen in onion
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