Rohitashav Singh

Optimization rate of pinoxaden + clodinafop-propargyl for weed control in wheat

A field experiment was conducted during 2011-12 and 2012-13 at G.B. Pant University of Agriculture &Technology, Pantnagar to study the effect of different rates of pre-mix of pinoxaden 2.53% + clodinafop-propargyl 2.53% on population and growth of weeds and grain yield of wheat. Major weed species identified in the experiment were Phalaris minor, Avena spp., Chenopodium album, Anagallis arvensis, Polygonum plebeium, Melilotus indica, Coronopus didymus during both the years. The lowest density and biomass of grassy weeds were recorded with pinoxaden 2.53% + clodinafoppropargyl 2.53% at 60 g/ha. However, it was ineffective against broad-leaf weeds. Maximum grassy weed control efficiency (100%) was observed with pinoxaden + clodinafop-propargyl at 60 g/ha closely followed by its lower dose applied at 50 g/ha and pinoxaden at 50 g/ha. Pre-mix of pinoxaden 2.53% + clodinafop-propargyl 2.53% at 60 g/ha produced highest grain yield (4.5-4.6 t/ha). Uncontrolled weeds caused 55.7 and 52.2% reduction in grain yield of wheat when compared with weed free conditions during 2011-12 and 2012-13.

Management of complex weeds in sugarcane by ametryn + trifloxysulfuron

Field experiment was conducted to evaluate the bio-efficacy of ametryn 73.15% + trifloxysulfuron 1.85% W.G for the management of grasses, sedge and broad-leaf weeds in sugarcane. The experiment consisted of nine treatments laid out in randomized block design with three replications. Cyperus rotundus, Ipomoea spp, Brachiaria reptans, Echinochloa colona, Digitaria sanguinalis and Dactyloctenium aegyptium were observed as major weeds. Among herbicide treatments, the lowest density of total weeds was observed with ametryn + trifloxysulfuron at 1500 g/ha though the differences were nonsignificant when compared with its lower dose i.e. 1250 g/ha at 15 and 45 days after application (DAA). Application of ametryn + trifloxysulfuron 1250 and 1500 g/ha recorded significantly lower weed dry weight over any other herbicidal treatment at 15 and 45 days. Highest weed control efficiency of total weeds at both 15 and 45 DAA were recorded with the application of ametryn + trifloxysulfuron 1500 g/ha which was closely followed by 1250 g/ha. The highest cane yields (9.04 t/ha and 10.51 t/ha) were recorded from weed free plot being at par with hand weeding thrice at 30, 60 and 90 DAP.

Herbicides for weed management in direct dry-seeded rice

A field experiment was conducted during Kharif seasons of 2010 and 2011 to evaluate the efficacy of different herbicides and their combinations in managing weeds of direct dry-seeded rice. The major weeds were Echinochloa colona, Echinochloa crus-galli, Leptochloa chinensis among grasses, Caesulia axillaris and Trianthema monogyna among broad-leaved weeds and Cyperus rotundus among sedge. The lowest total weed density was recorded with azimsulfuron 35 g/ha and cyhalofopbutyl + ready mix of chlorimuron + metsulfuron 60 + 20 g/ha, which were at par with each other followed by fenoxaprop + ethoxysulfuron 60 + 15 g/ha and twice hand weeding at 20 and 40 days after seeding (DAS). The lowest weed biomass was recorded with combined application of fenoxaprop + ethoxysulfuron 60 + 15 g/ha and fenoxaprop + ready mix of chlorimuron + metsulfuron 60 + 20 g/ha. The highest weed control efficiency was recorded with twice hand weeding at 20 and 40 DAS (89.9%) followed by fenoxaprop + ethoxysulfuron 60 + 15 g/ha, fenoxaprop + ready mix of chlorimuron + metsulfuron 60 + 20 g/ha, bispyribac-sodium 25 g/ha and fenoxaprop 60 g/ha over the weedy check. The higher grain yield (3.50 t/ha) was recorded with twice hand weeding (20 and 40 DAS), which was at par with fenoxaprop + ethoxysulfuron 60 + 15 g/ha followed by bispyribac-sodium 25 g/ha alone and fenoxaprop + ready mix of chlorimuron + metsulfuron 60 + 20 g/ha.

Azimsulfuron as an effective herbicides against sedges in transplanted rice

A field experiment was carried out at Pantnagar during Kharif seasons of 2013 and 2014 to know the bioefficacy of different doses of azimsulfuron 50 DF against sedges in transplanted rice. The soil of the experimental field was clay loam in texture, medium in organic carbon (0.67%), available phosphorus (29.6 kg/ha) and potassium (176.4 kg/ha) with pH 7.2. Major sedges were: Scirpus roylei, Cyperus iria, Cyperus difformis and Fimbristylis miliacea. Application of azimsulfuron 17.5, 26.25 and 35 g/ha with 0.2% surfactant and 35 g/ha without surfactant provided complete control of Scirpus roylei, Cyperus iria and Cyperus difformis. The lowest dry matter of weeds was recorded with azimsulfuron with 0.2% surfactant from 17.5 to 35 g/ha, which was found at par with azimsulfuron 35 g/ha without surfactant. Among herbicidal treatments, the highest grain yield (6.12 and 6.09 t/ha) was obtained in azimsulfuron + 0.2% surfactant at 26.25 and 35 g/ha, which was significantly similar to azimsulfuron + 0.2% surfactant 17.5 g/ha and azimsulfuron 35 g/ha without surfactant.